Robot

I'm putting together a robot that will be used to trundle around the house, hopefully picking up dirt and so on. That's the plan anyway.

The design is an octagonal base with two stepper motors as drive wheels. An arduino Mega will control the robot, and there will be sensors for bump-detection and maybe position determination.

The stepper motors are geared down, and the gearbox has a 6mm shaft witha 5mm flat. I couldn't find any wheels that fitted that shaft so I printed some:

I'm not sure how well the elastic band tyres will work, I may have to find some other grippy way to do tyres.

The stepper motors are mounted with printed parts too:

The stepper motor drivers are individual PCBs, I printed mounts for them too:

I'm probably going to mount two battery packs, one for electronics and one for the motor drive. This should keep noise from the motors at a minimum and should also allow the electronics to still function when the motor drive is dead. I could them switch the motors to use the electronics battery pack and limp back to a charging station. For now the robot will flatten it's battery packs and they will have to be removed to be charged externally.
Anyway, more printed parts hold the battery pack:

The arduino Mega has a prototyping shield on it, where I will add extra circuitry and also attach the motor drives and sensor inputs.  It is also mounted with printed parts:

The parts are mounted on a plywood base, this is octagonal and will have bumpers on each edge for collision detection:

Bumpers next, they are a bit tricky as microswitches aren't that straightforward to mount. I've started with a single printed bumper which contains two microswitch mounts and some flexible spring parts. So far I have quite a few iterations of the bumper:

In that photo the first bumpers are on the right hand side and later iterations are to the left.
They still need a bit of work, but they are nearly there. I need to make sure the switches are operated from all directions and everywhere long the length of the bumper.

I also have an ultrasonic sensor that I may mount on a servo so I can measure distances in different directions.