Battlebots 2020 Episode 1 review Part 3

I will be reviewing the fights from the new episodes of Battlebots. This is my personal opinion of the robots and the fights. I am not reviewing the show but rather writing down my thoughts on how a fight was won or lost.

Lock Jaw vs Captain Shrederator

This is a battle of the old guys. Donald Hutson and Brian Nave have been around for many years and have really refined their robots. Lock Jaw is a great modular robot that Donald can modify quickly to match any opponent. Donald is also a thoughtful but aggressive driver who can also addapt quickly to a changing situation during a fight. Captain Shrederator on the other hand has been having reliability issues the last few years. The reporting pre-fight explains that Brian is using an older version of Captain Shrederator but the shell design doesn’t look so old to me. Perhaps they are referring only to the mechanical/electrical design of the internals.

Donald has chosen to use the angled anti horizontal spinner bash plate for the rear of Lock Jaw. The design of the plate is the same as one we tried a long time ago on Scarifier and is made to deflect a horizontal spinner upwards. It is a proven design but Donald will need to be careful to not let Captain Shrederator around the sides of the robot as the bask plate does not extend far beyond the wheels of Lock Jaw. This shouldn’t be a problem as I said earlier Donald is a careful driver while Captain Shrederator is hard to orientate and has trouble with trying to manoeuvre around other robots.

Donald doesn’t start the fight with a box rush but instead carefully approaches Captain Shrederator to make sure that Lock Jaw connects with the bash plate. Donald was probably not worried about Captain Shrederator getting its weapon up to speed as the idea of the bash plate was to cause Captain Shrederator to damage itself. The shape of the plate worked as Captain Shrederator has thrown into the air. However the plate of Lock Jaw broke and exposed one of the rear wheels and the second hit damaged a tyre.

Donald must have seen that the damaged plate was not going to work and instead spins up to go for a weapon on weapon hit. The hit launched Captain Shrederator across the arena and into a corner of the box. The corner of an arena is the worst place a horizontal spinner can be when trying to start a weapon. Captain Shrederator as walls on 2 sides and Lock Jaw on another preventing preventing the weapon from starting. One of the changes Brian made to Captain Shrederator was to swap the weapon speed controller for a contactor. This means the weapon is either on or off and the current draw for the weapon motor trying to start must have been huge. This is obvious by all the smoke.

Brian manages to escape the corner and move to the centre of the arena but Captain Shrederators weapon is cooked. Lock Jaw is also having weapon issues but this is now a pushing match which Captain Shrederator can’t win. After a short time Captain Shrederator is caught on the screws and Donald holds back waiting for the ref to begin his count.

Sporkinok vs Rusty

This is the opposite of the last match with two first time robots. Sporkinok is an axe or lifter robot. In this fight Lilith Specht decided to remove the axe and just run as a lifter. Rusty is a pure junk robot that lives up to its name. Rusty is also an axe robot built by David Eaton out of junk he found on his parents farm.

Sporkinok started the fight well despite having some control issues with the robot. This was probably due to the wheels being so far behind the centre of gravity of the robot. Sporkinok was able to flip Rusty onto its side and it took David a while to get Rusty upright. It seems that there is a several second delay from when David fires Rusty’s axe to when Rusty actually responds which is seen later in the march as well. After the first flip Sporkinok is not able to lower it’s lifter completely and also seems to have even more trouble driving. This allows Rusty to haphazardly drive around to attack the rear of Sporkinok and bring it’s axe down on the drive Sporkinok. I am not sure if Rusty’s axe actually did any damage but Sporkinok was unable to turn or reverse after this attack and become stuck against the side of the arena. K.O. to Rusty.

Battlebots 2020 Episode 1 review Part 2

I will be reviewing the fights from the new episodes of Battlebots. This is my personal opinion of the robots and the fights. I am not reviewing the show but rather writing down my thoughts on how a fight was won or lost.

Malice vs Axe Backwards

This was a fairly straight forward and predictable match. Malice is a a basic horizontal spinner that is known for having what is described on the Battlebots website as a horizontal drum spinner. It is just a medium diameter thick disc but whatever. Axe Backwards is a lot more interesting as it is one of the only “full body” drum robots. Full body refers to the design of drum surrounding the whole robot with the motors, electronics and batteries being inside the drum with the wheels running on the drums axle out of the ends of the drum. The name of Axe Backwards refers to 2 tails shaped like axes sticking out the back of the robot that allow the drive motors to have something to push against but give the robot the appearance of a overhead thwack bot.

A great part of the full body drum is the same as a shell spinner like Megabyte or Spinderella. Since the weapon surrounds the robot all the weight of the armor can be put into the weapon. The problem with a full body drum like Axe Backwards is the wheels are so exposed unlike a shell spinner where the wheels are under the shell. Since the wheels are on the same axis as the drum the wheels diameter has to be larger than the drum + teeth to maintain ground clearance. This also means that the wheels also stick out in front of the drum and when fighting a horizontal spinner the wheels will be hit first. In fact Kurt Durjan needs to be very precise with his driving for Axe backwards to hit with its weapon before a wheel contacts the opponent. Unfortunately the worst opponent for Axe Backwards is a horizontal spinner like Malice.

The fight went exactly as I thought it would with Malice taking out one of Axe Backwards wheels in the first hit. Malice also damaged a fuel supply for a flame thrower that was mounted inside one of Axe Backwards axes but this didn’t seem to be critical. What seemed to be more critical is that the power switches for Axe Backwards, which must be mounted where they can be quickly accessed are in the axes where it was hit. But every time that Malice attacked Axe Backwards a wheel was the first thing to be hit. After 1 minute Axe Backwards was counted out.

Skorpios vs Bloodsport

Skorpios looks very similar to last year and is the classic overhead saw robot with a very solid wedge. Bloodsport on the other hand has been completely redesigned from last year. It is still an overheard horizontal bar spinner but no longer has the circular chassis but now looks like a smaller Son of Whyachi. I really liked Bloodsport last year but it had some reliability issues.

The fight starts with the usual box rush from Skorpios but Bloodsport was able to avoid it. Bloodsport is obviously afraid of Skorpios front armour and instead attempts to drive around the side to attack Skorpios’ wheels. Zachary Lytle was able to keep Skorpios pointed at Bloodsport so Justin Marple had to drive Bloodsport into Skorpios wedge. The hit didn’t damage the front armor but instead spun Skorpios around and Bloodsport was now able to attack the right wheel of Skorpios. The only damage made during this exchange was that Bloodsport lost 2 of its wedglets. This repeated a couple of times until Bloodsports weapon slowed and Skorpios was able to shove Bloodsport into a wall. However the overhead saw was damaged and Skorpios was not able to use it.

Zachary looks very confidant in the front armor of Skorpios and it looks well deservered as Bloodsports hits many times but does no damage. That is until Bloodsport caught the edge of the wedge and starts to peel it off. At this point Justin Marple is heard saying that Bloodsports weapon was overheating and needed to cool. This is not something I have heard very often with most robot drivers just repeatedly yelling “Spin Up!!” and damn the smoke, especially if the other robot is showing signs of damage. But Skorpios is not looking good with the right hand wheel clearly not working and smoke coming from the hole that had opened up on that side of the robot. Bloodsport starts the weapon up but does not use it and waits for Skorpios to be counted out.

This was a great fight between two solid robots. It really looked like it could have gone either way for most of the match. It also really shows how aggressive a driver can be when they are confident that their armor can hold up.

Battlebots 2020 Episode 1 review part 1

I will be reviewing the fights from the new episodes of Battlebots. This is my personal opinion of the robots and the fights. I am not reviewing the show but rather writing down my thoughts on how a fight was won or lost.

Sawblaze vs Whiplash

I great fight to start the season. Both Sawblaze and Whiplash are very well driven and very reliable. Jamison Go has a very aggressive driving style with Sawblaze constantly ramming opponents to push them into walls and pin them. Matthew Vasquez of Whiplash is not as aggressive but has excellent situational awareness and is able to quickly take advantage of any weakness that his opponent shows while accounting for any problems with his own robot. I was looking forward to this match with my prediction being Whiplash to win.

When the robots are revealed a point is made of Whiplashes tall vertical front armour plates. The idea is that these will counter the overhead saw of Sawblaze. I was a little doubtfull of these as the tall armour would only protect from a head-on attack. After both robots attempted to manoeuvre around each other and then made a couple of head-on attacks it became clear that the tall armour also allowed Sawblaze to win the wedge game. Jamison repeatedly drove Whiplash into the walls but seemed to wait for a pin before using the saw. However Matthew realised that while being pushed from behind that Whiplash would be able to use its weapon as an overhead saw the same as Sawblaze and managed 3 or so hits on the top of Sawblaze. It was great to see the rapid adaptation to the driving and attacking style of Whiplash when it became clear that Sawblazes wedges where always going to get under Whiplash.

But Jamison Go was always on the attack and did not give Whiplash more than a couple of seconds to recover and it was always going to be Sawblazes fight. Once Sawblaze was able to get to the sides of Whiplash then is was very quick to cut into the top armour and take out the drive of Whiplash. Aggressive and powerful driving with effective wedging really won this match.

Fusion vs Madcatter

Fusion is the anticipated dual weapon robot built by Reese Ewert of team Whyachi. Fusion has both a horizontal spinner on one end of the robot and a vertical spinner on the other making it look like a robot designed by a 5 year old. It is well built and very compact with the Whyachi robots being known for being quite pricey with no expense spared in either materials, components or manufacturing techniques.

MadCatter is more of a classic 4wd vertical spinner design but does have a self-righter that doubles as a lifter. This shows a lot of thought has gone into the design as weight has not been wasted on a single purpose self-righter. While MadCatters creator Martin Mason brings a lot of energy to his on-screen antics MadCatters driving is more subdued. This might be more to difficulty MadCatter seems to have turning.

The fight starts with a classic box rush from MadCatter. However a box rush on Fusion is only going to hinder the front facing weapon unless it can be pushed back into the wall. In this case the vertical weapon was hindered but the horizontal spinner was allowed to get up to speed. Despite the vertical weapon on Fusion being stopped Reese still insisted on driving Fusion forward into MadCatrer rather than turning around. Since MadCatter was sluggishly turning to face Fusion it would have been the perfect time to use the horizontal weapon. The seconds after the box rush shows the lack of awareness from both drivers. Fusion should have turned to use the faster spinning weapon and MadCatter should have driven forward to put more distance between itself and Fusion before attempting the sluggish turn to face it’s opponent.

It doesn’t take Reese long to realise he is using the wrong weapon and turns to use the horizontal weapon. This is when we get to learn why having both a vertical and a horizontal spinner on the one robot is a bad idea. Normally when a robot hits with a horizontal spinner it is jerked sideways due to the hit. With the vertical spinner creating its own gyroscopic forces the sideways motion the robot twists around an axis perpendicular to the axis of both weapons and Fusion flips over. Fusion can’t have both weapons spinning at full speed at the same time and hit something with either weapon without the other weapon flipping Fusion over. The large shocks and twists Fusion takes seems to cause the electronics to short circuit. Seeing how little smoke was produced for the amount of fire that came out of Fusion my guess is that it wasn’t a battery fire.

KOB2 Diary – Part 5

Day 19

  • Read the plan for the day on WeChat. The production crew plan an attrition style competition. So many teams complain about this style of competition. I have to go and watch. Relax day cancelled.
  • The main complaints (mostly from English teams) are based on not being able to recharge or repair between rounds and that this will make the competition boring to watch. The production crew disagree, and I actually agree with them.
  • I arrive at the event and go to the tv to watch the filming of the team selections. I’m the only international person watching, as per usual. I don’t understand why the international teams don’t want to watch the selection process. It seems that they don’t care about who they’ll be fighting, or care about the tv side of the competition. No wonder they don’t understand what is going on.
  • While watching the celebrities chose their teams, Emma insults the other celebrities, who end up ganging up against her. She yells and storms out of the film set. I burst out laughing and none of the chinese people around me understand why. I realise I was they only person watching who understood what she was saying as I was the only person who spoke english. The TV version of the team selections on the show was edited. When the Soccer commentator celebrity ran to join a team, Emma stamped her feet and screamed, yelled that it was all unfair and ran out the door before the chinese crew could stop her. The rest of the TV version was filmed the following day, which is why Emma noticeably changes.
  • When Emma left the filming set, she ran past the tv that I was watching and toward the real pit. Her security team were caught off guard and couldn’t keep up. She went through the pits and her teams thought she was coming to talk to them, but she pushed past and went through the catering tent and toward the main road. Everyone was confused.
  • While I am explaining what happened during filming to the other international teams we get news that the Chinese government have decided to ban Americans from appearing on Chinese tv. Donald Trump seemed to have had another anti-china press conference. Filming and production seems to stop. The entire area goes silent for the fist time since I have been there. The fights were scheduled to start at 3pm. Nothing was happening.
  • There seemed to be panic from the TV and KOB production teams. People start discussing that they might need to refilm the show with Americans removed, including Emma. But that seemed impossible.
  • The production crew start asking the American teams if they had someone of a different nationality on their teams. Every team had someone, except Megabyte. I jokingly said I could join the team. Would have been cool to drive Megabyte.
  • Production magically starts up again. Fights start at 7pm. In hind sight I think the anti-america thing was just misinformation and the actual problem was the missing Emma. It took over 4 hours to find her and production had to stop with one of its stars missing.
  • The attrition competition actually runs well, apart from the judge screwing it up and awarding a tie for one of the fights. There was supposed to be three judges, each awarding their own score that add up to an odd score. It should have been impossible to award a tie. But since the head judge was the only one actually submitting scores (he usually handed over the final score card before the other two judges finished writing), the tie was based on the fact that he was a boxing/mma judge and it is acceptable to have ties in that sport. Ties in robot combat, and especially an attrition competition, should never happen. He was an absolute muppet. The production crew had to convince him to re-score the fight and not ruin the show. He was angry that they told him he was wrong. I overheard him say that he has more experience judging fights than any robot builder and therefore he has the right to change the rules and we shouldn’t complain. (can you tell how much I hate this guy?)
  • Head back to hotel at 10:30pm. No chance to have another underground fight.

Day 20 (Ep 9,10 and 11 filmed during these 2 days)

  • Deicide to stay in the hotel and relax. Leslie has left on a pre-planned holiday and won’t be back for a few days. We didn’t tell the production crew that we let her go as it would have got her fired.
  • Ask Melissa for another fight. Keep waiting for time in the arena
  • Hear that fights are running late again. Also that Emma has been replaced. Probably slowing things down. She probably had more tantrums that the show was unfair or rigged against her. She didn’t need to leave early for study. This was a friday and filming finished sunday. How bad was your time management?
  • Don’t end up going in.

Day 21

  • Decide to keep waiting in the hotel as Leslie is still away. If I went to the competition without her, she would not get paid.
  • Hear that fights are running late, again.
  • Also hear that Orby missed out on an after-hours fight again. Lots of teams still asking for this. Hear that the directors have organised some 4-way rumbles, but no idea if that involves us.
  • Don’t end up going in.

Day 22 (Final day of filming)

  • We wait for the last bus to allow Leslie time to arrive from the airport.
  • When we arrive Melisa finds us to ask if we will be ready for a rumble at 6pm. This will be a warm up for the grand finale. Also included in the rumble is 2BBQ, Purple Minotaur and Pink Beater. I finally get another fight.
  • Spend 4 hours putting the batteries in and chatting to random people. Find that the battery with a hole in it is actually holding charge better than the good battery.
  • Told to weigh the robot and move it to the arena at 6pm, so far on time.
  • One rumble is scheduled before ours. 3-way with Orby, Fire Wheel and Earth Mover. Was thinking these were not to be filmed and just for fun, which is why I was allowed to officially drive.
  • Fights getting delayed. First see the referees and judges turn up. But then the presenters turn up and the audience get excited. Then 4 knocked out celebrities turn up. The 3 team captains have to film a walk-on introduction and we are moved to wait in a war-room. We suddenly realise that this will be filmed and will be our only fight in front of the audience/celebrities. Only had to wait until the last day of filming for this to happen.
  • Watch the previous fight in the war-room. Feels strange to finally be on set.
  • I was then told that I couldn’t be in the filming. Connie had to do the entrance and drive the robot. I was allowed to do the weapon and stand behind her. But because they waited until 10 minutes before the fight to tell me, I actually left Connie’s radio at the hotel. I run to the pits and ask Cat King if I could borrow a radio. I give it to Connie and she pretends to use it. She was driving the robot with another teams radio that wasn’t even turned on.
  • Fight finally starts. Plan to be calm and watch the spinners. But Pink Beater charges at us and I take a swing. I fitted the robot with the spiky axe (was the only chance to use it) and it got stuck in the floor. I didn’t realise that 2BBQ was also coming and hit a wheel while I was trying to retract the axe. I felt that the fight was screwed in less than 15 seconds, again. One side of the robot just didn’t want to drive.
  • Spend the rest of the fight trying to be mobile enough not to be counted out. End up breaking two count downs and taking a few swings at other robots. However I don’t remember any details and the tv view of the fight was focusing on the other robots as it was thought that we were out. We ended up outlasting 2BBQ and Pink Beater before being counted out. I didn’t realise that the referee was looking for 3m of movement from the point of counting. I was just trying to move toward the robot that was circling me. This means that I was moving the robot in circles during our third count out and the referee counted us out.
  • I did a nice spin and axe at the end that launched the robot a good distance into the air, as a victory dance, because I thought the referee counted the other robot out. This wasn’t shown in the final edit of the fight. And the fight didn’t make it to air, probably because the elimination torniment ran so well and filled the show.
http://f.video.weibocdn.com/000Q6Qe5lx07xuXiYR5m01041201ZnL70E010.mp4?label=mp4_hd&template=852×480.24.0&trans_finger=24688dbb28e33d6dbc1a1e49b11ca05c&Expires=1589459660&ssig=e42zk3h0lv&KID=unistore,video
Link for rumble video (not on youtube)
  • While moving the robot to the pit I realise that a short has come back. But are then told to return to the arena for more filming before I can remove the covers and find the problem.
  • We get told that we have to film an advertisement for the energy drinks. Connie can’t drink it because she is pregnant, so I need to be a stunt drinker. Connie stuffs it up by pretending to drink.
  • Run back to the pit to make the robot safe and pack it in the crate. Connie wants to return to the hotel with Alice to begin packing there. I’ll stay at the competition to watch the finals.
  • The robot only takes 30 minutes to pack while watching fights on the TV. A lipo fire causes a delay, so I walk with Connie and Alice to the taxi.
  • Once back I follow the English teams to watch the fights from the audience. So much fun.
  • The final judge’s decision of the final fight between Vulcan and Drift is scripted. First close decision of the competition that was correct. I am sitting behind the judge and watch the whole thing happening. The fight involved a lot of attacks by Vulcan that caused it to drive up Drift’s wedge. Using the muppet’s judging system this would have given all the aggression point to Drift and thus he wanted to give the fight to Emma’s teams. The production team didn’t want this to happen and wanted the chinese team to win. I could see the main director tell the judge to make sure he scored the fight the correct way. So the aggression points went to Vulcan, which is how everyone is the audiance judged the fight. I could see the muppent going back to check his rule guidelines after handing over the envelope and looking upset that someone was telling him what to do.
  • The English guys that I was sitting with are told to move to arena to film a group of robot builders during the decision. I decide to follow and get in the way. I was in the group of cheering builders, see if you can find me. I walk out before filming has finished and the director’s laugh when they realise I was there.
  • We think there would be a bus for the hotel as a lot of teams need to catch early flights, but we are all told to stay.

Day 23

  • At 12:30am I am told I am needed for filming. Not sure why.
  • Realise they need to refilm the energy drink advertisement because Connie stuffed it up. They didn’t even use the add in the show.
  • Finally get on bus at 1:30am.
  • Wake up at 8am to finish packing.
  • At 11am I check the flight status of the flight to find that the flight from Shanghai to Guangzhou was cancelled. Message Leslie and Melisa to get it fixed. Lucky I checked, as no one was aware that it was cancelled.
  • Told we are moved to an earlier flight and to go to the airport immediately.
  • Arrive at airport at 12:30pm. 1.5 hours to get through check-in. Bloody slow line, trouble with Connie’s passport, extra check on suitcase and other stupid Chinese shit.
  • Check the ticket and find that it is for a 11:50am flight that started boarding 1:20pm. Fuck.
  • 30 minutes to get through security. Needed to have the batteries scanned twice. Why?
  • Arrive at gate at 3pm. Flight still delayed. WTF?
  • Go to find food. Eat quick. Hear the call for boarding. Arrive at gate and find everyone already boarded. How?
  • Get on plane, which sits on the tarmac for 30 minutes.
  • Arrive in Guangzhou with 3 hours to make the connection. Easy. No security checks and immigration was quick. Batteries stayed in the bag this time.
  •  Plane for Brisbane boards on time, but delayed on the tarmac for 45 minutes. What is wrong with Chinese air traffic control?

Day 24

  • Arrive back in Brisbane. Hooray.

Day 100

Once Huntsman arrived back in Australia I finally found what happened during the final rumble. The drive with the issue wasn’t the side that lost the tyre chunck. Instead it was a broken receiver wire that was cause intermitted loss on the other side. Should have added a cable tie to stop the wire from rubbing on the drive outrunner. No other damage and the robot was fine at the end of the rumble.

Day 365

Still haven’t received the second half of the build stipend.

New Z probe

The last thing I wanted to do for my UP Plus 2 rebuild was to change the Z probe. The original Z probe is a micro-switch that is attached to the hot-end before calibrating. The UP Studio software has a calibrate function to allow bed leveling before printing. The probe would be manually attached, the calibration routine run via software and then the probe removed before starting the print. The same procedure can be done through the Marlin firmware I am running and G code commands via Octoprint but it is a pain. I want to be able to just press print and forget it.

My old Prusa Mendel printer was capable of auto bed leveling via an RC servo retracted Z probe. This worked well with the only problems being the twisted frame of the machine causing issues towards the end of its life. I considered mounting the servo Z probe to the Up but wanted to try something new. I had seen non contact sensors before and wanted to give them a try.

After looking around the internet I settled on an LJ18A3-8-Z/BX 8mm Inductive Approach Proximity Sensor. This sensor will trigger when a piece of metal is brought within 8mm of its end. Since the bed of the Up is made of aluminium this is perfect. The sensors 8mm activation is repeatable to within ± 25um which is suitable for printing at 0.1mm layer height when printing on a raft like I do. The sensor is bolted onto the side of the hot-end adapter and can be manually adjusted without much difficulty.

Inductive probe mounted to the side of the hot-end adapter.

The wiring was a little interesting as the sensor runs off 12V but the Arduino take 5V inputs. There is a lot of discussions around the internet about how to interface these sensors with the Arduino with much arguing about voltage dividers vs opto-couplers vs transistor logic. I had a look at the sensors data sheet and saw that the sensor has a NPN Current-Sink output which means that the sensors output is grounded when active and floating otherwise. I checked that the Arduino input is set with a pull-up resistor and the firmware input is active low then connected the sensor output via a diode with the anode to the Arduino to prevent any 12V from getting through and that is it. Enable auto bed leveling in firmware and add the G code to the slicer software and now the Up is print and forget.

The last thing was to add a print job cooling fan and duct to the hot-end. This fan and the hot-end fan are both controlled via the RAMPS. The hot-end fan is on the third power output of the RAMPS and is set to turn on when the hot-end temp is above 50 degrees. The second fan is switched on via a relay from a spare output pin on the Arduino and is controlled via G code. All the wiring is brought up to the extruder via the existing Up wiring harness.

New power supply for my rebuilt Up Plus 3D printer.

With the addition of the Raspberry Pi to my rebuilt Up Plus 3D printer I now have three power supplies connected to the machine. The heated bed is using the original 19V power supply that came with the Up, the RAMPS 1.4 and hot-end are using the 12V supply from my old Prusa and the Raspberry Pi is using an old 5V phone charger. This is a lot to connect to start the printer.

I want to simplify things by just using the 19V supply and fit the machine with two step down voltage regulators. I would need one regulator to step the 19V down to 12V and a second to step down again from 12V to 5V. The 5V is easy as the Raspberry Pi Zero W only draws 250mW max so any USB power supply will work. I settled with a dual USB 15W switch mode supply that can handle 6V – 40V input. The larger supply and dual ouput would be handy if I add a WiFi camera later.

The 19V to 12V supply needs to supply the RAMPS 1.4, Arduino, stepper motors and the hotend. I calculated the peak power draw to be 30W (2.5A). I chose a 50W Power Supply Module that included an LCD display that shows the current draw and voltage. The Ebay listing shows that the unit can supply 35W constant without cooling and 50W with the supplied heatsink. I also added a cooling fan.

The supposed 50W power supply the couldn’t handle 30W

The first test run had the 12V supply showing peak current draw of under 2.5A so less than 30W but the heatsink was getting too hot to touch even with a fan on it. 10 minutes into the print the printer stopped with the 19V supply shutting down due to short circuit protection. The second MOSFET on the 12V supply had failed short circuit. I contacted the Ebay seller wh didn’t respond to any e-mails. Swindled.

With a doubtful attitude to Ebay sellers I decided to replace the 50W supply with a 200W supply. This new supply doesn’t have a fancy LCD but it shouldn’t burn up during basic use. I kept the cooling fan just to make sure and the power supply is cool during use.

The new 200W 12V supply.

Now with only one power cable this printer is almost looking finished.

Prowler at the 2019 Australian Feather-weight Nationals

Last weekend was the 2019 Australian Feather-Weight Nationals and Daniel decided the enter Prowler. Prowler has been fairly unchanged since last year except for swapping the friction saw blade with an all purpose demolition saw blade. The controls were also divided between Daniel driving the robot and Andrew controling the weapon. This is the first time with both of us controlling the same robot and was hoped to remove some stress from Daniel while trying to drive and operate the weapon at the same time. Oh, and a new paint job.

The competion was held over 2 days with 2 qualifying rounds held the first day. Prowlers first match was against a lifter called Pooper Scooper. Going into the fight we were concerned about Prowler being turned over but Pooper Scooper’s weapon failed early in the fight. The new saw blade worked well on the mild steel and UHMW Polyethelyne top on Pooper Scooper creating several cuts in the top. A nice win to start the weekend.

The second fight was against Bob who is a viscious looking horizontal spinner. The concern here was that the blade whould hit the spikes on the front of prowler and bounce up into the saw arm. Daniel decided to drive aggresivly to prevent Bobs weapon from getting up to speed. During one attempt at sawing into Bob, Prowler drove Bob into the arena wall and Bob bounce up into the saw causing the saws bearings to pop out. After this Bobs weapon also failed and it became a pushing match. Fortunatly Prowler was able to out-wedge Bob and the arm could also clamp Bob to help drive Bob into the walls. During all this driving and attempted clamping Daniel realised that one of Prowlers drives would cut out while the arm was being raised or lowered. Fortunatly Prowler still won the fight.

Upon returning to the pits I refitted the weapon axle and replaced the bearings and checked that the saw was running true. The drive problem while the arm was being moved was determind the be a low voltage cut-out of one of the drive ESCs. To test this the ESCs were swapped with Berserkers ESCs (because Beserker just happened to be in the car) and Prowler worked ok. Prowler would keep Berserkers ESCs for the second day.

The next day the 2 wins had allowed prowler to qualify for the top 16 finals. The first match up was against The Undertaker which is a under-cutter spinner with a 4kg weapon. Fortunately for us the weapon was not working as The Undertaker had burnt out all its weapon motors the day before. This left The Undertaker fighting as a wedge with extra AR450 plates added to its top for extra armour. While Prowler could not cut into the heavily armoured top of The Undertaker we still won by judge’s decision. Now in the top 8.

Unfortunately the 4th fight was against Abomination, an extremely powerful and well built vertical spinner. Daniels idea was not to box rush but to move to the centre of the arena and hope that Abomination would not want to attack Prowler head on but try to circle around us. Being such a powerfull vertical spinner Abomination would have trouble turning to maneuver around Prowler and Prowler could attack the side of Abomination while it was struggling to turn. Despite Daniels over thinking, Abominations builder Michael just drove head first into Prowler and out wedged us. Prowler was thrown onto its back but self righted quickly. Abomination continued to attack and hit the side of Prowler immediately and the shock caused the liner actuators cast aluminium gearbox to shatter and the saw dropped to the floor. Daniel continued to attack and Prowler was thrown into the air a couple of times before landing on its front with the 2 spikes and the saw touching the ground. With the linear actuator broken Prowler couldn’t right itself and was counted out.

So Prowler went 3 – 1 and ended in the top 8 which is pretty good. Abomination went on to win the competition with straight KOs so we lost to the best. No major problems to try and fix between fights and if we had a spare linear actuator Prowler could have been ready to go again in a few minutes. Quite a successful weekend.

Adding a Raspberry Pi to my 3D printer

Now that I have my 3D printer running reliably and the RAMPS 1.4 mounted I want to disconnect it from my laptop. At the moment every time I want to print something I need to connect my laptop and leave it connected for the duration of the print. There is an option to add an SD card reader to the RAMPS but that would also require adding a control panel to the printer. It is cheaper to add a Raspberry Pi.

I have been using OctoPrint software on my laptop which also has a pre-made Raspberry Pi ROM called OctoPi that can be loaded directly onto a Pi. OctoPi is designed for a Raspberry Pi 2B or 3B and offers camera support out of the box. Since I am on a budget I decided to just use a Raspberry Pi Zero W. There is several reports of OctoPi not running on a Zero W mostly because the single core processor can’t support running the server and the camera streamer simultaneously. Since I don’t even have a suitable camera I don’t think this is a problem.

After loading OctoPi and running through the setup the printer worked first time exactly as it did from my laptop. The next problem is that I wan’t to print directly from my phone. OctoPi has an option of adding a slicer plugin on the Pi and while looking through the options I came across AstroPrint. AstroPrint is a cloud-based 3D printing system that includes a selection of slicers. Files are uploaded to AstroPrint, sliced in the cloud and then sent to OctoPi via a plugin.

For quick prints of simple models AstroPrint works well enough but if the model needs some fancy slicing then it is better to use a desktop slicer. AstroPrint also does not include many options to control the printer so I still need to use the OctoPi web interface or an android app.

The next problem created by adding the Raspberry Pi is that it needs a seperate 5V power supply as the RAMPS cannot supply enough current for the Raspberry Pi and the Arduino. Now I have 3 power supplies plugged into the printer, a 19V, 12V and now 5V.

KOB2 Diary – Part 4

Day 15

  • Go into the competition at 10:30 while Connie and Alice stay in the hotel. Plan is just to chat with people and watch some fights.
  • I noticed all the eliminated chinese robots are moved to different benches, but the builders and their equipment are gone. Leslie tells me that the robots are paid for by KOB and must be left behind. The builders took all the spare parts and leave the empty chassis. The international teams are oblivious to this since they don’t really chat to the chinese teams.
  • Brian Nave is getting bored and is challenging people to a fight. We don’t know when the intruder robots will final be introduced into the competition and the teams are tired of sitting around and doing nothing. I accept his challenge to test his new robot and are told we can have the arena during lunch. But it will take 5 -6 hours to repair Huntsman as I haven’t touched it since it was eliminated and I left my batteries and radio in the hotel. Directors say it is ok and we can fight tomorrow.
  • Pull everything back out of the crate and start fixing. Requires 3 people to bend the side of the chassis into shape. I had Robert Nani from team Monster and a random chinese fella who was walking past stand on one side of the robot while I used Cat King’s giant wrench to pry the damaged side. Wish I took photos of that. Actually Robert was with me for the entire repair, trying to learn how I designed and built the robot. Severely underestimated that pink beater.
  • Robot almost ready for testing at 6pm, just requires some soldering for motor plugs. I was correct in the 6 hour estimation for the repair time.
  • Competition fights finally start, but apparently are only “practice matches” so that the celebrities can learn about the robots on their leagues. The builders don’t want to damage their robots in fights that won’t count and decide to not use their weapons. This results in some boring fights. Some Chinese men from the audience come to see my robot and are rather impressed. Would rather talk to me rather than watch the fights. The directors start complaining that the builders will win money for each win they get, so they should be trying to win, but the builders ignore them. I doubt the fights would get aired.
  • Catch a taxi for the hotel at 8pm rather than watch the fights and wait for the bus. Turns out the bus left at 1am.

Day 16

  • Head in at 11:30 to finish getting the robot ready. Just need to solder some plugs onto a new weapon motor and put in the batteries.
  • Told we can have the arena in the afternoon, but that didn’t happen. They were filming team meetings and didn’t want too much noise.
  • Put Huntsman in the test arena. Everything works fine. Drew a nice crowd.
  • KOB people still asking if I want to fight Shredderator. They seem to think it is a bad idea and I’ll just get destroyed. I just laugh.
  • Competition fights happen at night, 3 fights scheduled between two leagues. One league wins the first 2 fights, so final fight cancelled.
  • Told we can borrow the arena at 9:30pm
  • Huntsman been prepared all day, feel confident.
  • Put it in the arena. Word gets around and a large crowd forms, including Emma Dumont. I feel extra nervous as I can finally fight in front of a celebrity and show what they missed out on. The arena lights have been turned off and “need to rest”, so we have to find portable lights. Go to turn on the robot and sparks arc up from the screw driver on the drive side. Decide to dismiss it. When doing the prefight checks the robot fails to move. Go back in to check the robot and find the drive power is off. Try to turn it on, more sparks, power light comes on and then dies. I get asked if I can fix it in the arena, but I worry it is a battery short and decide that it will be safer to take it back to the bench for a complete check rather than risk a battery fire.
  • While getting the robot out I hear Emma making rude jokes about my robot. So annoyed and hate her. Other builders tell her to be quiet.
  • Bench check shows that batteries are fine and the power lines running from the left to the right side of the robot had been pinched between the frame and the weapon motor. Riding on the trolley over the bumps to the arena must have rubbed through the wire. Every time the screw driver touched the switch and the lid the robot would turn on. The sparks are the capacitors charging. Once the screw driver was removed the robot would switch off. The power light would stay on while the capacitors discharged. If I turned the power screw 2 more turns the robot would have turned on fine, but risked a short as the chassis was grounded.
  • Shredderator continues to drive in the big arena for practice. Fight postponed as their batteries were flat and the work crew wanted to prepare the arena for tomorrow’s filming.
  • Go back to the hotel. Not happy.

Day 17

  • Alice and Connie not feeling well, so I decide to stay in the hotel during the day. Send a message to Brian to say I still want to fight and he can call me if we get the arena.
  • New stroller arrives, so test it out by walking up to the big shopping centre for dinner. $35, bargain.
  • While eating dinner I watch a mother hold a small child while it went to the toilet in a rubbish bin. And then a few minutes later I watch a man search through the bin for a water bottle. I’ll never forget that sight.
  • While at the shops we get a message from Brian Nave that we have the arena for a fight. Quickly find a taxi and Leslie to head in. Connie and Alice stay behind at the hotel.
  • Fix the broken wire with an empty coke bottle to protect it from abrasion. Do 3 bench tests.
  • Head into the arena. Only a quarter of the crowd of the previous night. But that gives it a more underground feel, just like when I first started. Feel more relaxed.
  • Fight went to plan. Finally drove calmly. Drive slowly to keep the spinner in front of me. Use the armour to box Shredderator into a corner. One of the impacts breaks Shredderators shell and causes it to lose balance and affects its control. I tried to hit it with the axe, but it was in the far corner and the poor lighting made it hard to judge distance, so I missed. So bugger it, I’ll just keep ramming and not worry about being out manovoured. Get Shredderator into a corner and go in with the axe even though I can’t see. The robot bounces into the centre of the arena, but has lost drive. I hear the Shredderator team yelling about a fire and that it was dead too. Double KO.
  • Lost drive because the battery unplugged and weapon from a bent motor (again).
  • The KOB arena crew and Blanka Botz (only guys watching) give me the win. Claim victory. Head back to hotel. Only at competition for less than 1 hour.
  • Go back to the hotel and hear that Shredderator lost its shell and drive base.
  • Slept very well.

Day 18

  • Go down to breakfast. Hear teams at other tables talking about me and the fight. Several teams come to congratulate me.
  • Walk over to the convenience store before going into the event. Bump into John Reid who congratulates me on the fight. Almost cried. Last time I tried to chat to him was in 2005 when I asked on a forum about kinetic energy calculations for electric hammers. All my robots use the calculations from the ideas he gave me. No longer care about the previous 2 weeks.
  • Catch the 11:30am bus.
  • Spend the day slowly fixing the robot.
  • Several robots ask for a fight. Feels like builders have finally realised that I’m not a noob. Organise fights with Orby, Medusa and Ground Dragon.
  • Watch a few fights. No idea what stage of the competition we are up to. If I go back I’m going to take a white board to keep track of things.
  • Go back to hotel on the first bus.
  • Hear on WeChat that the next day will be interesting with a strange fight format, but unsure if we’ll go in. Maybe have a relaxing day.

Adding a heated bed to my rebuilt Up Plus 2

So now I have my rebuilt Up Plus 2 3D printer working I need to tidy up the electronics. To do this I downloaded a RAMPS 1.4 case off of Thingiverse and set to printing.

The first problem I had was bed adhesion. The buld plates that came with the printer are similar to a prototyping PCB perf-board with hundreds of tiny holes in it. The PETG filament I am using sticks to the board well enough but all the holes make for a really rough bottom layer. After a little Googling I found that the Up software slicer uses a raft for bed adhesion so I will try that. It took some adjusting to get the first layer height offset correct but it is working.

The second print on the rebuilt Up Plus 2 was a case for the electronics

The next problem was that the prints are warping badly. I had not wired up the bed heater yet as I still needed to change the thermistor. The Ups original 100 ohm thermistor doesn’t work with the RAMPS controller so I replaced it with a 100k ohm thermistor. With the RAMPS power supply set to 13.5V the bed could only reach 65 degrees celsius and even then took 45 minutes to get there. The recommended bed temperature for PETG is 70 degrees so the best I could manage was still 5 degrees too low.

While I had changed the thermistor I didn’t change the heater cartridge in the Ups bed which was designed to work with a 19V power supply. The RAMPS 1.4 has a seperate power input for the heated bed but a look at the schematic shows that the MFR1100 11A PTC resettable fuse is only rated for 16V. A look at how these PTC fuses work and at the datasheet for this particular fuse I see that the critical part is not the voltage but rather the power consumption as the fuses rely on heating of the internal elements for them to work. If more than 16V is applied to the fuse while it is failing then the extra power consumed by the fuse while the internal resistance rises can cause the fuse to fail in a non-resettable way. But since this is what fuses usually do I am willing to risk using the standard PTC fuse at 19V.

I wired up the original Up 19V supply to the 11A input and left the 13.5V supply on the 5A input of the RAMPS and gave it a go. Now it reaches the target 70 degrees in under 15 minutes and has no trouble maintaining that temp.

I had started printing the case for the RAMPS before fixing the bed heater and the case had warped and the print failed when it seperated from the raft 3/4 of the way through. Since it took 14 hours to print as much as I did I didn’t want to start again. I cut the part that printed successfully of the bottom of the model in Cura to finish the print with the bed heater active and then glued the top to my failed print. The pieces don’t quite match due to warping but I now have a momento of how the printer worked before the improvements.

Ramps 1.4 case for the Up Plus 2