Read multiple digital sensors over protocol

Hi there!!

I have 200 digital sensors that I need to read its state from a arduino.

What I was thinking about is to make something like digital leds, where i connect 200 IC's in series. the first IC gets a "start" signal over a input pin, and outputs a "done" over one pin, and its state over another pin for (as example) 1ms. the next ic, reads the done, and does the same as the pervious chip.. this way each chip outputs its state one after the other to a "main line" that can be read by the arduino instantly.

this has multiple problems:

  • its expensive to buy 200 programmable ICs,
  • its expensive to program 200 ICs.
  • its expensive to buy 200 additional components that are needed to drive the ics.

I was wondering if I am trying to reinvent the wheel.. Is there already a similar product that does the same thing, maybe over a standard protocol? I was not able to find anything.

I am not searching for a specific product, as it would be against the rules, but rather a name for this kind of components that could help me to find something online.

Thank you

Best regards

Igor

What are these sensors?

What about a series of shift registers ?

touch sensors.. they have either a +5v signal or 0v.

never used them. I will check them out thank you.

So you need to read 200 touch sensors?

Are they spread over a large distance?

Parallel-in, serial-out shift registers as suggested by @UKHeliBob would seem like a good solution. For example 74hc165. Each can read 8 touch sensors, so you would need 25 of them. Only 3 Arduino pins would be required. Each register will need it's own 0.1uF bypass cap, of course. Also, because the "latch" and "clock" pins of the Arduino would be connected to 25 chips in parallel, you may need to buffer those lines, almost any 7400 series chips can be used for that.

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.