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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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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UK Techfest 2011 Schools Events

The 2011 National Schools and Colleges Micromouse competition took place on Saturday 25th June as part of the TechFest event at the Technology Innovation Centre in Birmingham. After several years of male domination it was encouraging to see a strong female challenge by the girls of Central C of E School, Chichester and Wycombe High School. Indeed, the best all-round performance of the day came from Wycombe High School pupil Katharine Puttick, who won prizes in three different categories.

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Designing a phase lead controller

A PD or PID controller is probably the most commonly used type for micromouse motor control. It is not the only way to get the job done though. An alternative is the phase-lead controller. This is the kind of controller described by David Otten in his Circuit Cellar articles…

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Designing the motor controller

At the heart of a micromouse is usually a pair of position controllers. These maintain the mouse position for one of two kinds of movement – forward and rotation. Each can be configured independently. Like any position controller, the idea is to get a fast, stable response to changes in the demanded position…

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Characterising the drive system on the micromouse

Designing the micromouse motor control is a key task which will go a long way to determining the performance of the mouse in the maze.  Before that can be done, you will need to know the physical characteristis of the motors and the drive system. All that can be calculated as part of the design process but it is easier to measure it if you already have the mouse built…

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Setting up a gyro on the micromouse

Putting a gyroscope on the micromouse is pretty much standard practce now. Being a bit slow to catch up, I have just added gyros to both my mice. Since the mice run at 5V, I had to use the ADXRS300 and ADXRS610 gyros. The first job is to get them calibrated…

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