Digitally Addressable Sensors?

Question

I need to come up with a way to daisy chain a number of sensors together and uniquely read the high/low pin from them individually. Think Digital RGB LED http://www.adafruit.com/products/306 or I2C. I like how when you power the LED strip up, it assigns a unique id. Is there already a module that will do this?

amillen · Accepted Answer

Thanks to all that replied, many of you came up with different solutions, but I was looking for something a little more off the shelf. Looks like someone finally packaged up exactly what I was looking for! 1-Wire Two GPIO Controller Breakout http://www.adafruit.com/products/1551

Former Member · Answer

Alex, I think I'm starting to see what you're getting at. with the discrete inputs (the switches), will there be (say) 20 sockets into which a switch may or may not be connected or should I think more like an ethernet arrangement where each switch is completely self-contained, and if there's no switch then there's not even a socket for the switch? For the QTI sensor (looks interesting BTW), same question I suppose. Also, what sort of analogue resolution would you need? (just thinking about ADC method) You may consider one or more PIC devices, some of which have multiple analogue inputs. If the sensor nodes are to be self-contained, then each node could contain a PIC (they're relatively cheap) which themselves provide/support SPI/I2C (or maybe a UART chain?) to connect the chain. There'd be a little programming needed for the PICs, but each node would only require fairly simple logic. If you're not familiar with PICs, start by looking at the PIC16F886. I'm not saying that's the one to use, just a stating point. In reality you'd probably want a smaller (less pins) PIC. THere are plenty of examples of programming PICs available. Best regards, Charlie.

danteo · Answer

Hi Alex,

Take a look at this 1-wire network guidelines too:

http://www.maximintegrated.com/app-notes/index.mvp/id/148

Here is a reference schematic:

http://www.maximintegrated.com/app-notes/index.mvp/id/244

Hope it helps,

Dan

Digitally Addressable Sensors?

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