Hello all. I have a bunch or IR sensors the kind that look like a regular LED with the helmet top on it. And so for my project I need to read from dozens of them individually to see how much IR light they are receiving. I would like to do this with an arduino but an arduino board does not have that many analog inputs. Can anyone tell me how I can achieve this? Thank you for any help given.
Perhaps you might be more specific in what your project actually is. You are limiting any answers you get by not including enough information.
Ok thank you for telling me that. I am new to this forum stuff so I wasnt quite sure about all the information I needed to give. So for my project I am trying to create a touch screen for a medium sized screen. I dont want to do the big setup where people use a projector and an IR camera and stuff so I want to try to make my own touch frame. So my plan is to set up some IR LEDs on the top edge of the screen and the left edge. then on the bottom edge and the right edge I will set up some IR sensors to detect the ir signals coming from the LEDs and then when the signal is interupted then I will know that something is touching the screen then I can triangulate the position of the cursor from there. So Because of this I will need to be able to read all the IR sensors so I can tell if something is in front of them
You would have to design it very carefully, as light from many adjoining ir led's would be visible to the same receiving led. Perhaps place them in tubes to make them directional.
I don't see why you couldn't hook it up like any other matrix, just minus the inner grids. The transmitters just need power.
I dont know how to do that. As I said before there are only 5 analog inputs on an aruino uno(I think) that will not be enough to read all of the ir recievers. Could you explain how this matrix will work?
Read HERE
You need to figure the number of receivers you will be using. That is what matters as far as data goes. You said "a medium size screen", but that's relative to what? I have a 1"x1" screen, all the way to the 24" monitor I'm using. Figure a sensor at about an inch (I have big fingers), so a 12x12 screen would need 24 receivers and 24 emitters. All the emitters would just be ON, so a driving circuit would be needed.
Uno has 6 analog inputs.
Mega has 16.
Use several 8-channel ADC chips, with SPI interface for nice fast reading.
Basically this is what this project is. The Sound Square
No analogue reading required.
It started out as a touch screen, note you can only have one touch at any one time otherwise you get some phantom positions.
I did this in my pre Arduino days but the hardware can be driven by an Arduino if you want.