Front Sensor Replacement

My micromouse, Decimus 2A, has not been behaving well. The most notable problem is that detection of the wall ahead, and the distance to that wall has been erratic. Worse, the problem seems to come and go. For a while I thought I might have damaged an emitter or had a dry joint but, when I looked again at the calibration figure, the left front sensor was giving a reading much smaller than the right front sensor… (more…)

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Correct for errors in a cul-de-sac

While the micromouse is exploring the maze, there are plenty of opportunities for it to make mistakes and end up out of position somehow. Equally, there are plenty of places where there are opportunities to correct any errors that have occured. The single cell cul-de-sac or dead-end is a perfect place for both. (more…)

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I2C use on the STM32F103R Medium Density Devices

I2C or Inter Integrated Circuit ( sometimes just referred to as just two-wire interface ) is a great method of individually communicating with over 100 devices on only 2 wires. However I2C as a whole requires a reasonable amount of protocol overhead so its not the fastest method of communicating with outside peripherals. But it is very good at reducing wiring on space critical designs due to the fact that only 2 data lines are required to enter the processor. (more…)

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Zeetah VI Mechanical and Electrical design

I missed discussing a couple of items in the last post: How are we going to attach the motor/axle brackets to the board and how do we handle the gap between the hub/gear and the bracket. Our original thought was to reduce mechanical complexity of the bracket, we wanted to support having axles that go between both brackets on the mouse.

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Bluetooth Serial Link

bluetooth serial link

Getting data back from the micromouse is a bit of a pain. Constantly having to disconnect and reconnect the serial cable every time you need to get some sensor readings or a data log gets old very quickly. Especially if you have done it wrong like me and about one in five reconnects resets the processor. So, as a quick hack, I made a carrier board that will connect to the existing serial and other pins on board. The carrier has a speaker, a push button, two LEDs and a Sparkfun bluetooth serial link. While larger that I would like, the Sparkfun module runs from 5V and is already set up ready to go. On a future mouse, I will make provision for the RN-42 module which is much smaller and runs from 3.3V. By default, the link speed is 115k baud and so far it just works. Turn on the mouse, tell the terminal software to connect to the bluetooth serial port and you’re good to go. Visit the Sparkfun web site for more information about the module. The carrier is way too high and way too heavy to use at speed but it should be a great help when getting the mouse set up. I expect to put a simple command line interpreter on the mouse so that it can be controlled remotely.

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