Let's Make Robots!

ligaBot

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After a long hiatus, I decided to resume working on this project.

I bought a USB power supply, that easily powers the Pi with the camera module and wifi dongle running.
The 6xAA battery pack is now dedicated to the motors.

I also wrote an android app that communicates with the Pi over wifi.
The video shows the current state of my project.
I made the app with a smaller screen in mind, so it looks a bit strange on a tablet.
The laptop shown at the end of the clip shows the server software running on the Pi.

The next step will be to make use of the Pi's camera module. The plan is to either include a live feed in the android app,
or to write a web interface instead.

Update:
After a few failed attempts, I decided to ditch the lego.
This is what i ended with.

Update:
Camera module mounted on a small servo motor.

 

 

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Hello!

So, do you have a web server running on the Pi, and that's how you control it? I'm looking to do something similar, but am having issues with the control interface. 

Hey,

Sorry for my extremely late reply.

I don't know if it's still relevant, but not, I'm not running a web server.
I wrote a very simple tcp server in python that runs on the Pi, and clients
communicate with it over wifi.

 

Good to see another pi project here! cant wait to see your robot moving around.

I never did anything in python, so i have no idea of its capabilites, but software PWM will work fine. The Pi runs so fast, you can PWM from a shell script if you want and still get pretty good results. 

Hey, thanks for posting.

I'll definitely upload a video of it in action, as soon as I solve the power issue.

Yes, software PWM was surprisingly easy to implement. When I was researching the matter, I read several posts from people saying the only solution involved compiling kernel modules designed for software PWM. I guess It's a recently added feature in the RPi.GPIO library. 

Python is a very powerful - yet easy to learn - language. I've coded in a few languages, but python is the one I always return to. You should try, if you get a chance :) 

I'm also working on a pi bot, didnt do any work today otherwise I think it would probably be finished almost (I dont have any batteries to run it from :P).

If your rolling with python then seriously check out the RPIO library. Drop in replacement for RPi.GPIO but also has DMA based software PWM on all pins, pretty accurate too.

Could you not use the tablet battery for motors and AA's for pi or is the tablet battery just not quite powerful enough?

 

I'm aiming for a start here robot clone with ultrasound personally. Using CD's and alot of sticky tape for construction :P 

Hey.

Nice to see others making use of the Pi. I heard about RPIO, but I never tried it.RPi.GPIO has software PWM for all pins too, now. Works really well for my gear motors.

My gear motors want 7.2V, so the 3.2 from the LiPo is a bit low. It might work if I get a step-up voltage regulator, as it's a nice battery. I'm still considering whether I should try that, or just get another 4xAA holder and power the Pi with that. Both should work.

Good luck on your project!