4tronix Pibug 2WD
les pounder takes a look at a simple robot that can be built in less than 30 minutes without any special tools.
Les Pounder takes a look at a simple robot that can be built in less than 30 minutes without the need for any special tools.
Robots and the Raspberry Pi go hand-in-hand. There are countless kits on the market and all are vying to be the ‘best’ or ‘easiest’ to build and use. 4tronix has a long history of building robots specifically for the education market, and with Pibug we see their latest robot in its growing army.
Pibug is a little different to other robot builds. Rather than include a chassis onto which we connect our Raspberry Pi, the Pi becomes a major part of the chassis. Coming as a collection of three circuit boards, motors and screws, Pibug is held together via a series of brass columns that connect through the four screw holes around the edge of the Raspberry Pi.
Via a short series of instructions on the website we were able to build our robot in less than 20 minutes, including the wiring of two extra sensors (line following and ultrasonic.) The build required nothing more than a screwdriver and a ruler to measure the length of components. No soldering is required and the kits can be broken down into their parts for reuse in class.
Pibug is designed for Raspberry Pi models A, A+, B and B+. That means your Zero or original Pi will not fit, unless you are determined and have some spare parts. Powering the Pi and the robot are six 1.2V rechargeable batteries, giving us 7.2V of power. This is the recommended configuration, as 1.5V alkaline batteries may introduce a reset bug where the Pi resets when making a turn or rapid change in direction.
The batteries are stored in a holder atop the robot, with a connector to the board locking them into place. Just make sure to use the included Velcro strap to hold the batteries in, as a crash dislodged our batteries, launching them across the room.
The two DC motors are controlled via a DRV8833 motor controller, which is part of the middle PCB in the sandwich. This controller is a staple in the robot community as it offers ease of use at a low cost – a great entry-level motor controller.
Software for the Pibug is provided via an install script on the 4tronix website, and while this may not be the
most secure method of installing it, the code is fully examinable and installation is transparent to the user. Once installed we have a directory called pibug containing the library pibug.py, which has all the functions needed to control the motors and react to sensor input.
The library is written in Python 2, which is a shame as this will lose support in 2020. The code will work with Python 3, but you need to make a few changes to print statements, as in Python 3 they are written as functions with parentheses. Once this bug is ironed out the pibug. py library works well, and we can clearly see how to retrieve and store data from our sensors and control the direction and speed of the motors.
The Pibug costs £24 for the basic kit. Adding the extra sensors (which we used) takes the price to £32.15, which is a good buy considering how sturdy and easy to build it is. This is a ready-to-go solution for classrooms and those wanting to get started with robotics.
More advanced roboteers will need to look elsewhere, but as the target market for this robot is educational, 4tronix has hit the nail on the head! This is an ideal first robot that offers cost-effective, reusable parts.