Micromouse - Quadrature Decoders

I have started to develop the quadrature decoders for my mouse, a simple circuit and is mainly programming so its something I can do to break up exam revision.

Here is a picture of the setup:

The main board is an Explorer 16 with a 32 bit PIC microcontroller in there. I have the prototype board connected to the expansion socket and I am then connecting this to the breadboard. On here is a 16F88 and some i2c eeprom. In the back you can see the icd2 programmer.

I have written the software for the 16F88 to act as a i2c slave, and the pic32 talks to it fine and displays the response on the LCD (although took a while to get it all working). The code to decode the quadrature signals from the motors is in there but there is a small bug in the 16F88’s code which triggers a read at the wrong time. The idea is the main microcontroller sets a pin high to make a copy of the current reading and reset the counter, this helps with working out the age of the reading. If I work out what going wrong then it should not be too long before I can plug a motor in and see how it performs…

I also have my LiPo batteries, and gears and wheels for the drive. I am waiting on a pillar drill stand then I can finish making a prototype of the gearbox, and finally see if the motors I have are up to the job!

Posted in: Microcontrollers, Micromouse, Robots April 2008 No Comments Martyn

PICs FTW

ChipsWoo, new PIC’s. Microchip have released a new 32bit PIC. It seems to have a similar processing ability as the high end dsPIC’s, but should have increased data throughput. Although taking into account that there is only one chip in this series at the moment we can be sure that new and better systems will be released in the near future which will kick the pants off the older PIC’s.

To get into PIC32 microchip are selling an uber cheap development board for £25, its not currently in stock in Europe, but December 3rd 6th 10th more should be avaliable.

  • 72 MHz, 1.53 DMIPS/MHz CPU core
  • Up to 512KB Flash Memory
  • Up to 32KB RAM
  • + All the usuals (I2C, USART, SPI etc.)

http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=2591

Posted in: Microcontrollers November 2007 No Comments Martyn