How many walls do you need for a square maze?
At the Japanese contest, Peter said there is a closed form solution for the maximum number of walls a legal micromouse maze can have. (more…)
Simple font data for LED matrix displays
My next mouse will have to have one of those small LED matrix displays. Not only is it actually useful to have a way of getting some feedback from the mouse, but these days, you feel a bit left out without one. There are numerous examples of 5×5 matrix font data available but when you need to design special characters it can get a bit tedious. Not being able to find anything suitable to help me, that would also run on a mac, I turned to Excel for help… (more…)
ZVI Brackets
Pierre was debating whether to make the brackets and separate axles or make them out of one block.
Zeetah VI PCB assembly
After the PCB order had been submitted I created the BOM and ordered the parts from Mouser for delivery a couple of days before the PCB. I tried hard to reduce the number of different parts. One big change from Zeetah V (ZV) to Zeetah VI (ZVI) was that I changed all parts from 0603 to 0402 except when the power or voltage required the larger part. This made fitting the parts for ZVI easier but also made routing 0.2mm traces with 0.2mm space a little harder. This meant that there were very few ZV parts I could use on ZVI. (more…)
Tools – logic and protocol analyzers
Invariably during development you need to look at a small number of signals because the circuit isn’t working correctly. What do you do?
Bi level stepper driver
At the 2007 Minos micromouse conference, Martin Barratt gave a talk about his stepper motor driving scheme. For best performance, steppers really need to be driven by a high voltage. However, the current will need to be limited to prevent the motor overheating. Normally this is done with dropper resistors which waste all the energy or with chopper drives that can be relatively complex. Martin has an alternative approach that provides the high voltage needed to produce fast step rates and the low current needed to reduce dissipation and keep the battery size under control.