Raspberry Pi Devastator Robot #4: Pygame & Speed Control

[@RoboNuggie]

This video is why you garner so much respect Christopher, in an increasingly superficial society, you delve into the minutiae of how things work and why. Excellent. Thank you.

[@Hartley94]

thanks

[@gnarlestongnu637]

I would like to add that, on a completely superficial level, that robot is super cool and its face looks badass and if it tried to start a fight with me in a pub I would probably back down and buy it a pint.

[@DrBenChem]

Always nice to listen to you talk about electronics whilst I peel my potatoes

[@Cluffmaster1980]

I have built a robot following your Guides and I have even added a remote firework launcher using a quad relay board. Using 4x 18650 batteries the tank goes really fast as well. Thank You Christopher for the video`s on what to do, You are very clear with instruction. All I need now is a PTZ camera with a live view so I can then drive it up and down the street, on my WiFi Launching my rockets lol.

[@rogerkoh1979]

The tank is back. Speed control is added. Always nice to see the robot in action.

[@theoriginaldylangreene]

Just watching this made me feel like a child again. I wish we had stuff like this "in my day".....*groan*. Genuinely Your channel is one of the most reliable for good content. Thanks so much!

[@Hi-kq5rx]

I’ve been waiting for this video to come out for a while... it was definitely worth the wait, great video as usual Christopher 👌😊

[@ExplainingComputers]

Thanks -- I got there in the end!

[@Hi-kq5rx]

Great things take time, everyone knows that!

[@gravestoner2488]

@@Hi-kq5rx is that why I'm so slow?

[@SembeiNorimaki]

Great video! An improvement suggestion: If your robot gets out of range it will never receive the KeyUp event, so it will continue advancing forever. Solution: the controller sends the status of the keys every second not only when they are pressed or released. The robot has a timeout so if it doesn't receive an update every second it stops. You can test that by leaving a key pressed and switching off the controller, so it never sends the keyUp event and the robot initiates the emergency stop.

[@zeberto1986]

It’s always a good Sunday when @ExplainingComputers releases a video about the very thing I am working on. Thank you Chris.

[@rikprince8414]

Ok, loved the technical bits. But, my favorite thing about THIS video was the robot's frowny face! :)

[@rohanverma6058]

As soon as I thought you done with the pi zero robot, you strike me again with another video, really like it hope to see more.

[@resrussia]

Greatly enjoyed the latest installment of the robotics series. Keep up the good work!

[@lawrenceallwright7041]

Wife: "Raspberry pie? Why on earth would you possibly want a raspberry pie? You don't even like raspberries!" Me: (Points at Explaining Computers Devastator Robot video and whimpers.)

[@ExplainingComputers]

:)

[@JoseLopez-oz1xm]

Loved it, and I can't believe the Robot found a stick. How crazy is that? Great Job Chris

[@caw25sha]

If it was a robot dog it would chase after it and pick it up.

[@srtcsb]

This is one of my favorite projects; it's nice to see it filled out with some simple (but clever) code and improved hardware. Thanks for another great video.

[@wanyman]

Great video ! I love the robotic ones. Can’t do detailed stuff like this anymore due to health issues so I appreciate allowing me to live vicariously through you.

[@qwkimball]

Thanks for this. I started a project yesterday using the L298N, so the timing is impeccable, very much unlike my coding.

[@MayankJairaj]

😂🙏

[@LMacNeill]

So many opportunities for customization here -- one could modify the code to automatically slow the motors during a turn to make turning more accurate. And I see that when you let go of *any* key, all the motors would stop. One could customize that part of the code to check and see *which* key you let go of, so that if you, say, press and release one of the "speed" keys while holding the forward key down, it won't stop the motors until you release the forward key. So many possibilities here! Love it!

[@kriskruz3792]

And in next week’s episode I will show you how to build an AI-driven terminator robot 🤖 based on raspberry Pi ! 👍

[@satch174]

Fantastic series, just build this and enjoyed it a lot. Thanks for this. I changed 1 thing. I used pin 16 instead of pin 7. Because every pin above 8 seems to be in a "low" state. This way u don't need a switch. The robot will not move at startup. Hope this helps someone.

[@ExplainingComputers]

Thanks for your feedback, and I'm glad it was a enjoyable build. I must try the alternative pins. Thanks for the info.

[@NickCornaglia]

I thought I'd check in to see where you were at with the devestater project. So glad I did. I always enjoy your videos. I was hoping for a live view camera program but I'll take what I can get. Thanks for the video.

[@chuckmuckamuck8001]

The best video on KZbin right now, thanks! I have taken this up as a hobby and this is the next project.

[@dazryan3463]

I had been wondering if the Devastator would return for an update and not disappointed. Using PWM is definitely a much better approach to getting the robot moving in a controlled fashion especially with the hard plastic tracks. Looking forward to the next instalment

[@M6Props]

Great video Christopher! This series has been such a huge help in building my own Devastator Robot. Thanks for putting out an update to the code!

[@ExplainingComputers]

Great to hear that you have a Devastator too! :)

[@mightycain4725]

So happy your making more videos of the robots, I watched the others a few month back and it really got me interested in having ago at building one with my son. Hope you continue with the robotics videos. 👍

[@PS_Tube]

This robot project is interesting. And it looks stunning. A teeny tiny explorer.

[@andreasproteus1465]

Grown up men still playing with toys is bad news all around.

[@NickT6630]

@@andreasproteus1465 Im a grown up and still play with RC cars 😆

[@Peter.Sky.Walker]

That's what she said. =[

[@parrotraiser6541]

@@andreasproteus1465 How do you think new ideas get generated? Testing concepts on toys is a lot less expensive and dangerous than starting with full-scale hardware.

[@PeteVanDemark]

Kids fortunate enough to have access to Explaining Computers today, will be building the off-world rovers of tomorrow.

[@gregholloway2656]

Great video, Chris. If you want another programming challenge, try using the pwm speed control to make high speed turns when at speed 3. For example, run the left track at speed 3 while the right track is forward at speed 2. Should make a more gradual turn to the right. 😀

[@MayankJairaj]

Thanks I'll borrow this idea 👌

[@perrymcclusky4695]

So happy to see the robot back in the wild! Looking forward to your next video.

[@johnvirgin405]

AmAzInG! Thank you again for sharing your content. You have been inspiring and amazing me since the days of Sinclair magazine when I spent hours typing programs (code will always be called programs in my head) into my ZX81 and Spectrum.

[@SomeOne-rh5so]

Chris I respect that you share vs people all details and hope could encourage many guys. ))

[@serceband]

Thank you so much for this !!! Your Pi Robotics series helped me discover a new passion in life 😊 If there is anything I could ask, it would be super super cool if you could also create an episode explaining powering solutions for such projects in more detail. I built a line follower based on your tutorials but it's powered with a single 18650 and capacitor to save space and make recharging easier. I'm making another one powered by 2s battery (7.4v). Thank you again, I really like your channel!

[@ashikjana8287]

Even thought he has more than 700k subs he still soo underrated... I guess some humans don't wanna learn

[@RedMageGaming]

Worth the wait! It's been so long since our little treaded friend got some screen time. Would be great to build this out in a more 'client x server' style. With the devastator streaming a live camera feed to another machine where you could control it with a gamepad or something. As long as it's within wifi range fully remote control robotank.

[@barnowldroneservices2979]

Using pygame is rather ingenious. Nice work.

[@plica06]

This was a brilliant episode! Python code running on a Pi controlling a robot!

[@tpobrienjr]

Thanks for bringing back the devastator bot.

[@muddyexport5639]

Very good! Enhancement: A joystick to control by degrees via cartesian X/Y coordinates "while in motion" vs. key down input. (Hover Craft need also.)

[@1983Chriso]

Thank you very much Chris for the amazing video. I wanted to get in to pi robotics with my 5 year old this video has made me want to look in to it further.

[@ExplainingComputers]

Go for it!

[@AndersJackson]

You have an open loop control just now. You might also want to consider a closed loop controller, where you record the speed of the wheels (like number of ticks generated by some of the wheels in the transmition), so it can adjust the PWM so the robot is traveling in the expected speed, if it can. Not just guessing what speed it should have. Then you actually can lower the speeds. This should probably be a PID controller, which isn't that hard to do. Adjusting the P, I and D constant is a bit harder though (but to make it easier, just set some to 1.0 and some to 0.0). That would probably be a better start, and put that in a class so the controlling get abstracted away an easier to control from the rest of the program. Fun video, anyways. Thanks.

[@SuperHaunts]

So glad to see t hat the stick didn't get things stuck. I wondered what had happened to the devistator!

[@martinmchugh1924]

So happy to see this robot back again 😂

[@ExplainingComputers]

It is pleased to me back!

[@DimensionPardo]

Greetings, what program do you use to edit your videos and to record your screen?

[@ExplainingComputers]

Hello! :) I normally edit (and did here) in Premiere Pro CS5 (one of the last editions pre-rental). Else I use DaVinci Resolve. The screen is recorded in hardware, not software, using an HDMI recorder see my video here: kzbin.info/www/bejne/pqDGpGNojtp9as0

[@t8lucas]

I wish I could built one like that but for now I can only admire your work. Great project and hope to see more. Thank you 😊

[@alerey4363]

Great hack! You can default to speed 2 for turning so you are sure it has enough power to turn in a controlled manner (1 is not enough and 3 is too much for rotation)

[@ExplainingComputers]

Yes, it would be a good idea to do all turning at speed 2. And in forward or reverse, to increase speed the longer the key was held down. So many possibilities! :)

[@ahmad-murery]

Now just add some missiles and sirens then program it to recognize strangers invading your backyard :) Cool video as usual Thanks Chris

[@HickoryDichotomy]

Very cool indeed! Maybe a nice idea would be to code it so that IF left or right is pressed then a minimum 'tested' speed would be enforced on turning, but keeping the current rules in place for forward and back buttons

[@virgilmcmayers4974]

With daughter we also building the robot based on two raspberry pi computers. One is in the robot and the second is the control station. We realized for rotating the camera more suitable to use the separate turning mechanism based on the stepper motor with pre-programed angles to turn. Because you've noticed that tu turn the camera by turning the robot is not easy to catch the proper angle. Also you right that the final tuning of the rotation and speeds is necessary in accordance to the bot dimensions and it's motors capabilities :) One problem that the "real-time reaction" to the button press isn't working in our configuration bot control station. However we working on it now...

[@thomasburnett4712]

Thank you so much for yet another entertaining and informative video!

[@t5ruxlee210]

Operating the Raspberry Pi Devastator without a combination recovery vehicle/ maintenance and repair crane to hand is really tempting fate, Mr Barnatt.

[@mikebreakwell3909]

Great video as always! Really looking forward to more Pi robot adventures. I'd also like to see Chris put a Pi pico through it's paces

[@cokeforever]

Autonomous navigation with neural network and object shapes recognition seems like logical next steps for your lovely robot ;)

[@vassilisnikolaou7376]

That is awesome! Now I feel like I want to make one too, once I finish my Python courses!

[@SimopediaTech]

great informative video, thanks for sharing 👍🏼

[@bensekh]

Love your videos. This will be my next project.

[@techcracker4566]

Really nice video🤟. I want it to say that I really like the chassis of the Robot, it really looks aggressive 😁. I might have an idea for you to continue innovating with this robot: the next step could be streaming the picamera preview, using motion framework, over the internet.... That could be great because you will be able to control the robot without looking physically at it...😎 Anyways, thanks!

[@stuartg40]

I also used Pygame for this robot a few years ago. I too should probably dig it out for more experimentation. The original plan was to mount a pan-tilt turret on the top with a laser that could burst black balloons.

[@caw25sha]

Can you control a stepping motor? Would be good for a turret.

[@stuartg40]

@@caw25sha Yep, that was the plan.

[@robertomaximilianosilveira8768]

Wow Nice to see the robot again ... I love it.. i see it from the begining... Wee see this in Former future films now is real un your garden... Love it

[@dj_paultuk7052]

Neat!. Its like s 2021 version of the old 70's BigTrak.

[@delagum1]

Great vid! Now you’re making me want to get involved into the Raspberry.

[@ravesab]

We are in 2021, i wait for hovercraft robot video or another Raspberry robot video 🙏🏻🙏🏻🙏🏻. Thanks for your channel 👍🏻👍🏻

[@judsonleach5248]

"It's always exciting looking inside a robot, isn't it?" - Yes Sir! lol - Cheers!

[@karllaun2427]

At last! I've been waiting for this one. Time to bring the Devastator out of it's box...

[@polgzz]

This is SO good!!!😃👏👏👏👏👏👏🔝🔝. I didn't knew about this project, Chris, but I think it's fantastic. This is going to be the next present for my little niece! I can't wait to teach her how to build this (and lern myself!)

[@bg31337]

A live video stream over network would be awesome! 🙏

[@bigjim152]

Very interesting. Looks like the next project should be to add the code for 'sweeping up in the garden' to the robot capability!

[@onepalproductions]

Lovely stuff, thanks for sharing.

[@ExplainingComputers]

My pleasure!

[@ddiver2200]

Thank you for sharing knowledge, but can external control be classified as a robot?

[@Praxibetel-Ix]

I can't believe I watched all four parts of the Devastator robot saga in one sitting... ...it was worth it too! It does help to have a massive pile of laundry to fold while watching. Anyway, what a good robot it turned out to be. Are there still plans on making that hovercraft?

[@ExplainingComputers]

The Pi hovercraft remains an ambition!

[@Praxibetel-Ix]

@@ExplainingComputers One day... 🤞

[@williamgiddings9636]

Good fun Chris, especially during lockdown. BTW, what was the pile of bricks for?

[@ExplainingComputers]

It is a more a question of where they were from . . . ! :)

[@amaljazzam2127]

It's fantastic devaster I like I want to make it,thank you for the detailed tutorial

[@ExplainingComputers]

You are welcome 😊

[@sepgorut2492]

How about pre-programmed moves: turn 90 degrees left, wheel right, about turn, shoot the burgler with the laser etc?

[@ExplainingComputers]

Certainly possible -- I did the essence of that here: kzbin.info/www/bejne/d4u2mqSgZbONnbc

[@amirmukhlis4936]

Hey, that robot is awesome! Keep making great content man!

[@ExplainingComputers]

Thanks! Will do!

[@NickT6630]

Great video as always Chris! I think I need one of these but with a lawn mower attachment. How fun It would be to drive it round the garden while sitting in doors viewing through the camera.

[@SarfLondonWardancer]

Very interesting video. I'm curious when setting the speed are you automatically forced to have a maximum option of 100% ? If one was to type say 200%. Would the motor over clock and work at a higher speed until it burns out, or would the motor just run at 100% being its manufactured maximum?

[@ExplainingComputers]

A square wave pulse cannot be high more than 100 per cent of time. So you could not overclock the motor by trying to set a higher value -- 100 percent is "fully on". :)

[@SarfLondonWardancer]

Thanks

[@heinrichkeyser4217]

Great video. If it were a true 33% and 66%, you would have first had to test what the minimum pwm for the robot to move is and then work with that as the minimum and not 0. But I'm sure you know this and this was definitely enough to get the point across😊

[@cossakrose]

Chris: "Devastator, will you be my Valentine?" Devastator: "After all this time?" Chris: "Always."

[@NicoDsSBCs]

Nice to see the bot back. He still looks menacing. Would be cool to have a nerf gun on it as cannon. Have a nice evening Christopher.

[@Pekitos]

Like always mr. SATURN... morning! Great video!

[@felipesqr]

Great video! i forgot about the speed thing.. I assume that you can make it turn while going foward if you set a lower speed in one of the sides while going foward.. Also i great part 5 would be LIVE VIDEO FEED and yet over wifi controls.. than you could control it from a phone connected to it via wifi for better range (i'm trying to figure it out actually)

[@ExplainingComputers]

You are right, you could all manner of gradual turns by running one set of tracks slower than the other. I may well stream from the camera at some point. :)

[@dany08011]

Oh god the baddest of pi cases!

[@LeftoverBeefcake]

I'm modifying a Tomy Omnibot to give it more modern capabilities and better mobility, and this looks like the perfect chassis to use in place of the crusty old rubber wheels and under-powered motor that it came with.

[@czarczarczar]

Hi Chris love this video and all of your raspberry pi rc robot videos ! Is there anywhere I can get the pygame code you created ?

[@ExplainingComputers]

The code is accessible from this page -- www.explainingcomputers.com/pi_devastator_videos.html -- under "Episode Four". This link is in the video description. :)

[@czarczarczar]

Thanks Chris!

[@AMDRADEONRUBY]

Nice video as always hope you had a nice week.

[@featherpony]

How about left + up runs left tread at 50% speed and right tread at 100%?

[@NicolasChapadosGirard]

Math... Go to know the difference in distance and how much you want your forward turn... Everything could be done with time and practical test.

[@Reziac]

So I have a question -- can you change speed while the robot is moving, or only while it's stopped? Had missed its earlier adventures so this was my first experience with those mysterious GPIO pins. :D

[@ExplainingComputers]

Yes, speed could be changed by moving code-wise, but not with keyboard control if motion is controlled by holding a key down.

[@Oogobuk]

Should have the arrow keys determine how long it was pressed forward, and change the pwm based on how long you hold it down.

[@ExplainingComputers]

A possibility, certainly.

[@lowiehojas5525]

You are such a great person! great mind you have. Thank you for your videos. You make it easy to understand things that are complicated for me. much respect to you Sir! Have you tried setting it up as a live feed? where you have also a monitor on your controller :)

[@ExplainingComputers]

Thanks for this. A live video feed is on my list!

[@lowiehojas5525]

@@ExplainingComputers yay, great! looking forward to it :)

[@kentswanson2807]

outside?! What a strange and wonderful place you have discovered. Scary.

[@ObsidianMercian]

Wonderful video Chris! Thank you.

[@pyanehemehem3685]

thanks for this exciting episode

[@dylansullivan9229]

Thank you for a great video 👍

[@Igerster80]

Did anyone else notice the time on the computer? Appears he pulled an all nighter working on this.

[@stephenhargreaves9011]

Oh, for the speed, hook it into a timer so that it will always start slow an accelerate the longer the direction key is pressed. That way, you don't need to manually select the speed, and you can, in fact, have it range rather than be on fixed values. Noted that to slow didn't provide enough power, but you could simply map a range to ensure that minimum power is sufficient. Maybe include a toggle override (that locks the speed) for those situations where you want a constant speed.

[@robertmaxa6631]

Looking forward to seeing the hovercraft in action.

[@VeryUsMumblings]

Surely a robot called 'Devastator' can deal with a stick... oh,, wait...no... oh, ....YES! Ha! That will teach that stick!

[@TopHatCentury]

I love the concept of small robot projects like this one. It is fascinating how this specific model of robot can run on a few AA batteries and an external ppwer bank. I was curious about whether buying rechargable AA batteries for this robot would be as effective than with traditional alkaline AA batteries.

[@netadmin-fraser787]

One more upgrade consideration, controlling it via SSH and maybe a battery life indicator?

[@matthewfelgate]

Nice project thanks for sharing. Do you think you could run a robot like this from a microcontroller?

[@ExplainingComputers]

Yes for motor control, but not if you wanted to record or stream video.

[@NickCornaglia]

I'm still hoping for a live surveillance video edition of the devastator robot. Do you think that's possible in the future?

[@ExplainingComputers]

Certainly!

[@rysterstech]

I know some battery Banks out there have the ability to report their battery state over USB I wonder if this could be used to get a low battery warning whenever the battery reaches say 15%