Thursday, July 28, 2016

St Kwan's Is Expanding

We would like to welcome Kirktopode to the St Kwan's Family! He has the goal to enter the embedded electronics field, and I have the goal of completing the robot without going crazy. We are perfect for each other!

Also, all of the robot code and design stuff is now on Github. Kirktopode is holding the master version, and I have a fork of it. I am using another one of my projects to hold the wiki in which I am documenting things in English.

Sunday, July 24, 2016


Last year I tried to implement a wheel encoder in between heats and failed. The ambient light was just too bright. So this time I am building the wheel encoder into the gearbox. I took the spare gearbox apart to see what the best way to do it is. Inside the casing is a differential gear in the form of a cylinder with gear teeth around the outside and the differential gears inside. The cylinder is sealed, held together with 4 screws. But, the outside of the cylinder is perfect for my design. The gearbox cover plate in that part of the gearbox is relatively easy to remove, and in just the right spot. If a hole is drilled through that plateau optical sensor can be set up to look through the hole and read the half of the differential cylinder face which is painted white. Two such sensors can be used to mak single-track quadrature encoder, which can tell whether the wheel is turning forward or reverse.

I have a pair of QRF1114 sensors specifically designed and obtained for this purpose. This part is basically just an infrared LED and an infrared phototransistor in the same case. It isn't directly useful as-is, but I combined it with a few resistors and made a three-terminal analog device.