I’ve been working off-and-on on an all-wheel drive robot that interfaces with my android phone/mac/windows machine via an adhoc wifi network created on the robot itself.
I created a custom handshake to go between the robot and whatever device is connected to it, allowing the ability for the software to set the speed and direction of each individual motor, independently. So far, the code for the microcontroller and windows machine is finished. Now, I’m just working on building up the hardware to run it.
Since I don’t have all of the mills/lathes/time I need to build a chassis, I started looking around online for pre-made kits (and really, let’s be honest, the mechanical stuff is the boring part — 😉 ). I got the robot chassis that I wanted as a gift for christmas from my beautiful wife, Jess. The one I asked for was the A4WD1 with no electronics from lynxmotion. It’s real basic; it comes with the chassis (made out of aluminum), top and bottom panels (made out of lexan), 4 dc motors, and the monster tires you need to run over stuff.
I was able to hook up my breadboarded circuit to it after I assembled the chassis, and the motors ran great (although, they aren’t as fast and as powerful as I’d like, I might look in to upgrading the motors later). The circuit I built is just a standard full h-bridge that can accept pwm inputs, then multiplied the circuit by four. An h-bridge is probably the most common concept in simple motor control design.
So, the next step is to lay it out on a pcb, and then get it fabbed. I’ll put up the schematic and pcb layout when I get done with it. I think I’m going to try out this new fab shop that was recommended to me called pcbwing. In the past, I’ve used expressPCB for these kinds of projects, but I hate how they limit you to using their software (though the software is pretty nice for small projects). Once I’m done with that, I’ll continue working on the robot’s software. Namely, integrating it with my phone, being able to control it with the built-in accelerometer. That way I can move the robot by tilting and moving my phone, while giving a nice touch interface for i/o.
Some basic components that I’m using so far:
- Rabbit BL5S220 Single Board Computer
- Lynxmotion A4WD1 with no electronics
- TB6549HQ Full H-Bridge
- Various caps and resistors