New hardware!

After breaking the z-axis connection on my first device I ordered a new KXPS5 accelerometer from crodnet on ebay. I really recommend this seller, he’s very cheap and sends things rapidly.

I quickly knocked together a circuit on veroboard and hooked up the base of a transistor to the freefall / motion interrupt pin to check it was working. It is remarkably sensitive, the LED flicks on if i drop my pen at one end of my desk when the device is at the other! I was quite pleased that everything was working well so i hooked it up to the I2C bus using the cable kit kindly supplied by www.andahammer.com. Using I2C tools i was able to set registers and read acceleration vectors without any trouble so i’m pretty sure everything is working well. I was a bit worried about exceeding the bus capacitance at first.

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It turns out that i can still use the old device if i rely on the internal low pass filter. I was thinking of doing this anyway and using a Kalman filter to process the output. First i need to write a device driver so i’ve rapidly being trying to learn C. So far i’ve got a very basic kernel module up and running on the mini2440 🙂

4 Replies to “New hardware!”

  1. Nice surgery on the cable kit. Is that 0.1 perf board? It looks like you could use some 2mm board so all the kit connectors will work out. Looking but have not found the right combination of price and quality.

  2. I want to know – what is that black connector that goes to the cable called. I’m having a lot of difficulty getting a hold of that cable to get to my GPIO pins. I can’t get them from online (no card!) – so i need to find the cable in some shop.. but which kind of shop can i get them from?

  3. Sorry i can’t help with the part number, but i can tell you it’s the same pitch as a 2.5″ IDE HDD connector. At one stage i butchered one of these for a sensor. Some pin header which you can cut to size would probably be the easiest thing to find in a store, or you could make a ‘squid cable’.

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