Robotics Research
To see my latest progress in electronics and software, please visit the page on BreadBot.
Pictured above are three MC908GP32CPE microcontrollers from Freescale Semiconductor. The electronics for the robots will be centered around these microcontrollers, which conveniently come in a 40 pin PDIP case with .1" lead spacing for simple breadboarding. With 32 kilobytes onboard flash and 512 bytes onboard RAM, I will have plenty of breathing room when it comes time for writing the software.
Thanks to P&E Microcomputer Systems, I now have a programmer for the microcontrollers. They graciously donated a USB-ML-MON08 Interface Pod to my research effort. To see a demonstration using the Interface Pod, visit the LCD Demo page. The LCD Demo was a quick project I did just to get familiar with programming the GP32 and provide a debugging aid.
Eventually the microcontrollers will be used to connect the motors, which have magnetic encoders, and the other sensors that will be on the robots to a wireless link with my PC. To do this, I will be using a Bluetooth modem called the BlueSMiRF available from Spark Fun Electronics.
At this point it seems that I will be using optical sensors on the robots in the form of infrared proximity detectors to detect obstacles and also infrared floor sensors to pick up grayscale values from the floor directly beneath the robots. Both types of sensors would provide data to assist in mapping out the area of study. I may need to use smaller, supplemental microprocessors to distribute the workload for the sensors.
Pictured above is one of the six battery packs that will be used to power the robots. Each consists of six 2300-2800 mAh AA NiMH batteries to provide a total of 7.2 V. The power supply uses a low dropout linear regulator to supply a steady 5 V to the control circuitry, while the motor drivers are attached directly to the 7.2 V supply.
The schematic of the power supply I have designed is available here. This is very similar to the power supply used on BreadBot and it appears to be very robust and reliable. The header at the top might attach to a separate circuit board with the microcontroller on it, but I will probably integrate this power supply into a control circuit on a single board. The headers on the left of the schematic will connect to the 10 position socket connectors that terminate the motor cables.