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Topic: Retrieving analog velocity signal from laser mouse - Question about Due (Read 1 time) previous topic - next topic

fishbulb

Hi All,

I always love coming here for help. I've set  up this exact mouse sensor tutorial on my arduino

http://www.instructables.com/id/Arduino-Tutorial-ADNS-9800-Laser-Mouse-Traveled-Di/

Ideally, I would like to pull the velocities off of the Arduino as an analog signal. My thoughts were to try to get this to work on an Arduino Due and use the analog outputs of it to get the analog signals of the voltage. The data we are looking for would be around a 100 HZ sine wave, and so we would like to sample a bit about that (~500 HZ). Can the Arduino Due cleanly output signal this fast? Is there a better way to achieve what we want. I figure that building our own DAC for a Uno is probably overkill.

Thanks for the input and cheers,
FB


rogerClark

I'm not precisely sure what you are trying to do, but the DUE has a 12 bit DAC, so you can create realistic sine waves using this output, and if you only want to create 500hZ, then allowing for 10x oversampling, you'd need to write to the DAC at 5kHz

I took at look in the spec for the Atmel SAM3X8E used in the DUE but I didnt see any conversion time listed for the DAC, and if its just resistor ladder type, it would be exceedingly last
So I can't see a problem running an interrupt at 5kHz on a CPU running at 84Mhz to index into a sine wave lookup table of 1024 integers
Freelance developer and IT consultant
www.rogerclark.net

fishbulb

Thank you rogerClark. Yeah, it seems like this should work. I'll have to give it a try and see how it looks.

Thanks again,
FB

rogerClark

Cool.

I have a Due on order, so I may have a play with the DAC as well, as its somthing that is missing from the original Arduinos

Freelance developer and IT consultant
www.rogerclark.net

fishbulb

Great. Well if you happen to find anything out about the Due that you think might be trouble (large noise or inconsistencies) for me and you happen to remember this thread, just let me know.  Wow that was a run on sentence.

FB

rogerClark

My board won't be here for a few weeks, as I only ordered it yesterday and I live in Australia, so most things have to come from over seas which can take ages. e.g. minimum time from Europe is around 5 days, and a lot of places seem to send stuff 2nd class which takes even longer

But I'll let you know how i get on.

PS. I could probably buy locally, but it would cost at least 2 or 3 times the online / overseas price.
Freelance developer and IT consultant
www.rogerclark.net

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