2 weeks ago

RockyBorg review

PiBorg offers three-wheels of madcap mayhem with its latest robot kit.

RockyBorg (£99/$135) is a slightly madcap racing robot from PiBorg, the geniuses behind Formula Pi (Raspberry Pi’s premier AI racing competition). This latest creation follows in the tyre tracks of MonsterBorg and DiddyBorg, but with a significant reduction in price and complexity, and one less wheel. Indeed. This is the first three-wheeler we’ve tested at Raspberry Pi towers. And we’re entirely smitten.

Most of the robots we encounter have steerable front wheels, or a tank-like differential steering (where the speed or direction of the left and right motors are adjusted to turn). RockyBorg does things differently. Two 180 rpm motors on the rear provide forward momentum, while a servo tilts the whole body of the robot (including an affixed front wheel) to change direction. The result is a trike that tilts into corners. Everybody we’ve shown RockyBorg to has loved it.

This article first appeared in The MagPi 85 and was written by Lucy Hattersley

The on-board Camera Module (not supplied) tilts with the body, leading to some great race footage. This YouTube video shows RockyBorg in all its epic action.

RockyBorg is also good value at just £99. This includes the acrylic parts, servo, and two motors, plus the new custom RockyBorg motor controller. You also get the on/off switch and battery compartment (but need to supply your own AAA batteries).

The supplied motor controller is similar to the PiBorg’s ZeroBorg, with support for the two direct motors and a single servo.

All the parts included with the RockyBorg build. You need to supply your own Raspberry Pi board and Camera Module

You need to bring your own Raspberry Pi to the party, plus a Camera Module if you want to add vision to RockyBorg. It’s not a complete kit, but you can use it with most Raspberry Pi boards.

Ours was built with Raspberry Pi Zero WH, but we’ve also tested one with Raspberry Pi 3A+. All recent models of Raspberry Pi can be mounted to the side, and PiBorg is developing an add-on for Raspberry Pi 4 that adapts the ports on the newer board and adds a 3 A power supply.

Building the RockyBorg

RockyBorg is a clever design. It features two vertical plates around the front wheel, and a top and bottom plate (both made of acrylic). These clip together to box in the battery compartment, keeping it secure and adding stability to the centre of the robot.

Your Raspberry Pi board sits attached to the left plate, and the RockyBorg motor controller fits on top of Raspberry Pi. The wires from the motors feed through the back plate, through a hole in the top, and out another hole in the left.

It is a fiddly thing. Take a look at the RockyBorg build instructions in order to see what’s in store. It’s not a particularly difficult build, but be sure to follow the instructions carefully. There’s a lot of looping of wires and cables that needs to be done with precision.

Once the robot is built, the wheels must be calibrated. PiBorg has a calibration guide which enables you to test each motor is working correctly and set the default return position for the robot.

Dual DC motors provide forward propulsion, while a servo motor tilts the body to provide steering

Then it’s on to the software installation, which pulls code from PiBorg’s GitHub repo. The code enables remote control of RockyBorg with a Bluetooth controller (we tested it with a PS4 gamepad). And much fun is to be found jamming the RockyBorg around. RockyBorg also responds to a web interface, which provides camera feedback.

From there, you move on to the API interface. It’s still a work in progress, and we’ve recently seen OpenCV support added, so hopefully you’ll be able to use it to test out self-driving in the future. How easy this will be with the tilting camera will be interesting, though. Our experience with remote control and Python testing was fabulous.