Mr Bit at PiWars 2017

It’s been two whole days since PiWars and we are still buzzing with the excitement from it, it’s bound to last for many more days and beyond. The challenges weren’t easy and the work put into getting there the biggest challenge of all. Very naively we assumed it would be a very simple task to put a robot together but …

full picture of mr bit with gripper pipper attached and golf ball in place

Mr. Bit Gripper Pipper

Generally we try to give our posts meaningful titles but we couldn’t resist coining our slightly deranged golfing challenge device the “Gripper Pipper”. It’s a simple device at the front of Mr. Bit to grip a golf ball then hit (or rather “pip”) when releasing. The gripper is a 3D printed claw modelled in Tinkercad, it has a basic cog/gear …

Following the Minimal Maze Wall

This might be the challenge we’ve been dreading the most, solving the minimal maze. We’ve thought about a few ways of doing it, using sensors to see the best route available when reaching a wall, using a compass to turn the correct amount when needed and our preferred solution happens to be the simplest, following the wall using PID control. …

Raspberry Pi Line Following with QTR-8RC and WiringPi

Our Pololu QTR-8RC sensor has taken a lot of work to get consistent readings and line detection working from the Pi directly, we’ve persevered with it and IT WORKS! We’ve yet to find a good working example running directly from the Raspberry Pi so we hope this post will help others who are also trying to use the module. We …

Sharp Distance Sensors and Straight Line Challenge

We are using Sharp distance sensors on Mr. Bit which can read a distance around every 16-20ms, apparently slightly slower than digital sensors though we have the advantage of having a distance measured (our sensor actually the GP2Y0A41YK0F which has range 4cm – 30cm). To make use of them we are using a GrovePi+ which manages ADC for us, the …

Controlling Mr Bit with Dualshock 3 Controller

We tried out using an app on an Android phone to control Mr Bit but we decided that it was going to be difficult to create an interface that would allow us control our robot sufficiently. We have now tried control with a Dualshock PS3 sixaxis controller and we’ve decided that this is the way forward. To do this you …

PoC – App Inventor 2 to Control our RPi Robot

Controlling MrBit will require a user device and we’ve taken a look at using my Android phone for this. We have a bluetooth connection set up on the pi in anticipation for needing to control our robot and we need a user interface (UI) on the phone. Here’s how we made our proof of concept Android app using MIT’s App …

Grove pi on top of mr bit complete shassis

Building Mr Bit’s Chassis

Mostly we’ve been testing out the electronics for Mr Bit and learning about motor control all the time itching to drive Mr Bit too. Without a chassis though we weren’t going to get very far. So last week with some aluminium-rubber laminate board off-cuts from a sign-writer and a number of nuts, bolts and stand-offs, as well as motor brackets …

Robot Batteries – Power vs Weight

I’ve always been tall so have at times been on the receiving end of a driver saying “you can tell you’re in the car” referring to my size/weight having impact on the car’s speed/power.  So this is what this decision is broadly based on, what batteries should we use in Mr Bit to make sure we get the best power …

Pololu QTR-8RC sensor on RPi

We are using a Pololu QTR-8RC line following module. This sensor array has 8 IR LED/phototransistor pairs and provides a capacitor discharge that we need to time in order to work out any relative reflectance – lower values would be lighter surfaces to higher values. The sensor array is powered by 3V3 (5v default, converts to 3V3 by bypassing a …