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16  Forum 2005-2010 (read only) / Interfacing / Sensor suggestions wanted on: April 30, 2009, 05:40:56 am
I am working out how I can create a midi-enabled recorder (musical instrument using an Arduino. I therefore need to detect which holes are covered by the player's fingers and I'd be grateful for any ideas on how to do this.

My first thought was to use light sensors but the light levels present in an open hole might not be very high, particularly the thumb hole, which is underneath. I've not been able to find a light sensor which detects the difference between low light and no light. Most seem to be best between bright light and low light.

Mechanical switches would be ok but only if they don't need to be clicked or have anything but minimal pressure applied.

I'll need 9 or 10 so the price has to be reasonable.

All suggestions gratefully received.

17  Forum 2005-2010 (read only) / Interfacing / Proximity sensor with varying levels on: June 25, 2008, 04:33:29 am
I am starting a project and would be grateful for any hints.

I need something similar to the common IR LED and phototransistor proximity sensor. These measure the reflected light from an object and switch on at a certain point. They have a pulsed signal to avoid false triggering by ambient light. What I require, though, is a rough measure of the amount of reflected light rather than just on/off. 3 or 4 bits precision would be ok. All the circuits I have been able to find just switch on and off and don't offer a varying level.

Secondly, I need 10 channels of the above so I'd like to have as few components as possible duplicated 10 times!

It would like to use an Arduino to process the input from these sensors so am looking for something easy to interface.

Any ideas gratefully received. Pointers to circuits or chips or suggestions for alternative approaches would all be great. Thanks in advance.


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