So to help test out the Core Motion Shield I’m working on, which will provide direct control of Four Brushed DC Motors or Two Stepper Motors, Multiple Servos, process the inputs from SR04/SR05/Parallax Ping/Maxbotics Ultrasonic and Sharp IR Distance Sensors and provide a 6-Axis Accelerometer+Gyro interface, all over I2C.
Anyway, I picked up some parts from Pololu to create a little Spark-Powered Robot—affectionately named Sparkoid—to assist me in my plan to take over the world the design and testing of the Motion Shields.
Right now she features two High Power 150:1 Gear Motors, each with dual optical encoders inside the wheel hub, which monitors the actual wheel rotation, as opposed to a shaft encoder which motors the raw motor output. These are mounted to a 5" Diameter laser cut acrylic base, on top of which is a 5" Diameter protoboard. There’s an HC-SR04 Ultrasonic Rangefinder mounted to very front for primary collision avoidance, plus 4 Sharp Digital Proximity Sensors mounted two on each side (perpendicular to the wheels) and two in the rear (45 degrees from dead center); this provides non-contact object avoidance when backing up and going through narrow passages (as opposed to using microswitch based “Cat’s Whisker” sensors).
On the main board is a socket for the and a 20-Pin MSP430 (to consolidate all the sensor data), plus a DRV8833 dual channel 2A motor controller breakout and a 1.5A Buck Converter breakout. I’ve got a Gyro and Accelerometer breakout coming early next week.
The whole thing is designed to be powered by a 7.4V LiPo pack.
Ideally, once I get the Motion Shield done, I’d like to make a custom White 5" PCB as well, with a socket for the Core and all the necessary headers, plus an on-board two-cell LiPo charger and buck converter for users to easily build their own robot! (You can tell this Pololu board was designed way back, as it has a footprint for a 9-Pin Serial Connector on it.) Perhaps even a custom iOS or Android app that lets you control the bot by tilting your phone.
So this thread will serve as a build-log and to garner feedback!