Servers by jDrones

Ardurover Project Using Lego Technic RC

(Michel Seguin) #1

Hi all, first post here, but been doing lots of reading.

Really interested in the Ardupilot project and it’s various forms. Because I like to bite off more than I can chew, I’m looking to take a Lego Technic RC tank type thing (see image linked below) and wire it up with some Ardupilot hardware & a sonar sensor.

The RC in question:

The control hardware set I’ve been looking at:
https://bit.ly/2m0tpit (Links to an Ebay listing)

Now, from my understanding, I’ll have to look up the datasheet for these motors so I can plug in the values to ArduRover; and I believe these are brushed motors. Aside from the PWM setting, is there anything I’d need to drive these motors via ardupilot?

I’m also wondering if, since I’m replacing the control module with an ardupilot kit, if I just get rid of the existing battery and get a proper lipo & power module for the ardupilot board.

Links to good reading material on the subject greatly appreciated

(Dave) #2

I suppose you could get that vehicle running with Ardurover but you don’t want to use an APM flight controller. They are obsolete and haven’t been supported with firmware updates in >4yrs. Looks like space for hardware is a bit limited so I would look at an F4 or F7 board. If you think a Pixhawk will fit you could go that route. You will likely need another RC control system. Hopefully the ESC’s used take standard PWM input. They probably do. Lot’s of good info here. Review the setup for skid steer.
http://ardupilot.org/rover/

(Michel Seguin) #3

Yeah, been reading through ardurover’s documentation.

Thanks

(Dave) #4

I have built a couple rovers from off-the shelf RC trucks. A 2wd basher and a 4wd crawler. They were both really fun projects. The crawlers performance is excellent. I haven’t built a skid steer vehicle but there is a lot of experienced users on this forum that have.

(Michel Seguin) #5

Neat. What control board do you recommend? Previous poster said the APM one I was eyeing is no longer supported

(Dave) #6

The easiest to implement would be a Pixhawk but they are physically the largest. The best bang for the buck may be an Omnibus F4 Pro V3. I used PIxracers on the 2 Rovers but mostly because I had them. The F4 and F7 boards require a bit more tinkering and a lot more soldering but they integrate a few things on the board (direct battery input, voltage/current monitoring, OSD).

1 Like
(Michel Seguin) #7

Thanks man, appreciate the answer

(Sebastian Schürmann) #8

You will need brushed ESCs or a dual brushed motor controller. The Lego IR receiver is driving the motors forward/off/reverse, no proportional control. The motors themselves are just that, motors. Than you need to cut a Lego power functions cable in half and solder standard RC connectors to it. Crimping servo connectors should also work. You can than use the two cables as adapters to the motors, keeping them usable with Lego hardware. I do not have the pinout, but a multimeter will help. Keep the racer together and meassure which pins do what, while you are running the motors.
If you do not have a multimeter at hand, I can meassure the pinout for you tomorrow.
Lego runs on 6x1.5V AA, but the batteries are depleted really fast. I modified my sons battery boxes, so they take 2s 800mah lipos (we use those) or 3s lifepos. They last much longer, are faster to load and can deliver more amps.

(Sebastian Schürmann) #9

I just converted one of my sons tracked racers to standard RC. You need only the inner two cables, these are the ones used for motor control. The outer two cables are constant power.