DoodleBorg: a three-horsepower robot tank

PiBorg are an organisation making add-on boards for your Raspberry Pi. Recently they produced the biggest and most powerful Pi robot we’ve seen so far, using one (six, actually) of their motor boards: the resulting DoodleBorg is a three-horsepower beast powered by motorcycle starter motors. To all intents and purposes, it’s a small tank. With a dear little nobble on top for hitching things to.

The DoodleBorg has a Raspberry Pi for brains, and uses six of PiBorg’s PicoBorg reverse motor controllers, one for each wheel. It kicks out 2.1 KW – which is to say, around three horsepower, or more than my French teacher’s car had. (We’ve been discussing in the office what you might be able to do with such a mighty robot: Clive wants to run a Magdeburg hemispheres experiment without the horses; I want to pull a tractor trailer full of builders’ rubble – unfortunately, I happen to have one of those at the moment. Dave wants to set up a tug of war against a class of kids, and then stick his car in neutral and tow it around a field while shouting “Yee ha!”.) We’ve never seen a Pi look so insignificant in comparison with the robot it’s powering: we see lots of robots which are basically a Pi on wheels, whereas the Pi is completely lost in the body of this one. Best of all, the whole thing is sent commands via a PS3 controller.

Did I mention that we think it’s completely brilliant?

Raspberry Pi IV Beginners (a YouTube channel you should really check out) went to interview Team Borg about their metal monster.

(Yakkety Sax makes even the best things better: ten hundred internet points to Raspberry Pi IV Beginners for observing this.)

You can buy PiBorg add-on boards for your Raspberry Pi (the LedBorg is a particular favourite in our office) from PiBorg’s website and from Mod My Pi. If you end up making something even a tiny bit as cool as this, let us know. We like robots.



Pedantic of Purley avatar

It kicks out 2.1 KW – which is to say, around three horsepower, or more than my French teacher’s car had

Highly unlikely Liz. I suspect your French teacher had a 2CV. Even the early models were around 9 horsepower. The 2 refers to the taxable horsepower and you really don’t want to go there unless you want an incredibly convoluted explanation.

liz avatar

That is a grave, grave shock. I’ve been under a terrible misapprehension for a quarter of a century. :(

JamesH avatar

I raced a 2CV in the 24hr race they have, top speed 76mph, with a highly tuned engine….they are not a powerful car.

AndrewS avatar

Could it tow both a Ben and a Gordon around Pi Towers? :-)

PETS – Pi Employee Transportation System

Andy avatar

So my neighbour parks his car where he dina orta; if I get one of those I could move it to somewhere he couldn’t find it
Of course he may have left the hand-brake on, so I’ll have to add a robot arm to lift the back end.
And if he’s awake, the music might give it away.

Ivan avatar

Undoubtedly it’s brilliant and I am sure really good fun !
But the maths don’t quite work out…6 x 10 Amp outputs = 60Amps
2 batteries, assume in series = 24 volts
24 x 60 = 1440 Watts (1.4KW) so very roughly 2 HP

Or can the PiBORG actually handle even more power ? ;-)

Cheers, Ivan

JBeale avatar

Good point, the Picoborg Reverse specs do say 5 A each channel or 10A combined. Maybe that is the DC-average limit, and 2.1 kW is peak power for short duration only?

RaspberryPiIvBeginners avatar

YEY love this tank. Was hoping to take it out sometime with the guys but weather was ….English (wet)

Thanks for the internet points.

Jim Manley avatar

OK, the mechanical engineer in me is in love. Another great class project to add to the growing list. Thanks for the inspiration, PiBorg folks! This is the kind of resistance being futile to which I would have no problem acquiescing! :lol:

His reference to RobotWars is exactly what I was thinking – they used to record some of the shows on Treasure Island (what a great place for the former Navy housing there, now inhabited by young public school teachers and first responders who can’t afford SF’s sky-high-and-rising rents). The hitch ball would also solve the problem of maneuvering my 24 x 8 x 8 foot workshop and aircraft transport box trailer in and around the hangar, as well as towing the aircraft around using a much smaller carbon footprint than my beater 1991 Chevy pickup truck used for utility purposes, which will now include transporting something like the Doodleborg (I could easily fix half a dozen of them in the bed). Too bad it was raining and that I had to park six blocks away a couple of weeks ago Liz, or I would have shown it to you and Eben – you would have had a good hoot … someday, someday …

meltwater avatar

Seeing that pic gave me an idea…

Raspberry Pi attached to helmet, with PiBorg XLoBorg and wireless connection to provide direction control.
You have your own wireless segway!
Suggest a tethered kill switch is added though or some walls will get destroyed.

Simon D avatar

I assume a RPi (+arduino) has enough grunt to make a segway clone.

An Australian company got a beefy Segway, armoured it and use is as a flexible target for use on live-firing ranges.

See what can be done.

Haggishunter avatar

I suspect the kids would win that tug o’war since even the best tyres provide limited traction, especially as the kids would presumably be pulling it slightly upwards.

Still, an excellent project. I’d start by hitching it to a full-sized vacuum cleaner for the house, then see if I could progress to a bucket and camera for self-guided poo picker for the horse lakefield.

AndrewS avatar

Just like a scaled-up version of

Ravenous avatar

Hmmm… anyone seen those electric motor kits that are used to nudge caravans around on site?

Just one point – the corner wheels on something like this may dig into carpet a bit indoors, when turning in place. It could lift your carpet up pretty quickly!

AndrewS avatar

Since each motor is individually controlled by separate motor controllers, I guess that’s something you might be able to minimise with a clever algorithm?

Although the robot doesn’t really look built for “indoors” does it ;-)

Mark Daniels avatar

Very cool! But, the numbers just don’t stack up.2.1 kW (2.9 h.p.) mechanical power from a bank of starter motors is going to require a very high input power as these motors are short-term rated and hence essentially run overloaded during starting duty and exhibit extremely low efficiency. Probably no more than 50% efficient. Losses in the controller probably amount to more than 10% at full load, so overall efficiency (ignoring further mechanical losses in the gearboxes, etc) is approximately 45%, hence electrical power input requirement is a staggering 4.67 kW!! That will require around 400 A at 12 volts or 200 A at 24 V! I suspect that the quoted power has been obtained by simply summing the quoted powers for the individual motors.

Nevertheless, this is a great project!

For comparison, my own ‘bot runs a pair of 2.2 kW 3 phase induction motors – that is continuous MECHANICAL shaft power! Peak rating for 30 seconds is twice that. We get about 3.5 kW at the tracks after the gearboxes and other losses. Supply voltage is around 300 volts d.c. into the drives. It doesn’t yet have a Pi for a brain, but I reckon it would be possible, given sufficient time.

killor avatar

I’ve commented on the forum and I think with this BOT adding a scissor lift and other accessories like camera, stickers (QR-CODE), some laser pointer and a barcode reader.

It can make a home version of the famous ROBOT KIVA used by AMAZON for managing your warehouse.

It seems silly but I use it for a home can be very useful and practical.

Imagine having a room in the house dedicated to store everything you need, clothes, shoes, books, records,
hard goods, etc.. all put in shelves.

If you need something, you ask the computer database and this tells the robot position in the shelf is the article and the robot brings the shelf for you to take hold.

Then go through the barcode reader to the database you know what you take with you to be updated.

To add items is easier Just call the robot and this brings a shelf and you’re being discharged article with scanner and placing it in the tray that tells you.
Forget ordering, software database will know where everything is.

All of this is real and is now using enterprise level.
But I think it would be feasible to do for homes.
This may be the beginning of the “BOT-ler” in the home. :))

Pygar2 avatar

You forgot to add a Babbage Bear to ride it… to add that air of class and quality, you know!

jesse avatar

add nerf gun, a little servo to rotate it, a cam module and vr glasses. fun guaranteed

ANDRY .JR avatar


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