The road to PiWars continues! Most important of all is a solid base to build from so that’s where we’re starting.

A render of the new design for the robot base. It has a mecanum wheel at each corner, these wheels have rollers around their circumference rather than a solid rim.

This is the first iteration of the base design, it’s the same width but slightly longer to give more room inside the enclosure. Another big improvement, I hope I least, is that I’ve added suspension to each motor.

As this robot uses mecanum wheels it’s incredibly important that all four always have contact with the ground as all four wheels work together to allow the robot to move in any direction, if one isn’t in contact then the effect that wheel would have won’t be present and it’ll veer off course. I’ve added a hinge at the bottom of each mount and the black part will be printed in flexible filament. By varying the wall thickness and infill I should be able to control how much travel each wheel has. That’s the hope at least…

Another improvement is for quality of life more than anything and that’s the method by which the upper part of the base (not pictured, or designed yet…) attaches. On the previous iterations of NE-Five these parts have been attached using tabs that are simply screwed in place, this makes working on the robot tricky as if I need to work on the wiring it’s not designed for it.

I’ve also made the switch from Red Robotics RedBoard to the Pimoroni Yukon, the RedBoard has served me very well but the lack of encoder support is a problem. There’s ways around it, like using the Pi to Pico adapter that Neil developed, but the Yukon has a motor controller and encoder module all in one. It’ll also allow me to control the torso actuator and LED lights which is another issue on the Pi.

The NeoPixel library on the Pi requires you to run it as root, this makes running it as part of a ROS launch file a bit of a pain. By handing off control of this to the Yukon that problem goes away.

The other big benefit of switching to the Yokun is that I can send it messages to do something and it’ll do it rather than using CPU cycles on the Pi. Splitting hardware up between real-time and scheduled systems like this is very common and should work a treat here. The Yukon runs MicroPython too so I should be able to use ROS Serial to connect to and have it act like a ROS node, which it will be but running on the hardware.

All of this is theory at the minute and there’s always little problems I miss until at least the third iteration, stay tuned to find out what mistakes I’ve made this time! 😅