Electronics > Beginners

Looking for a chip to reduce number of inputs to controller

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huangwm:
Sorry if I'm posting in the wrong section.
I'm working on a small hobby project where I need to detect a large number of inputs that are assembled in a grid-like fashion. The controller that I am using (arduino/pi) doesn't have that many inputs, so I guess I will need a converter chip to reduce the number of inputs into the controller.

I was hoping that the community would give some ideas on what chips I could use, or if there's an alternative idea.

Thanks alot!

Benta:
The easiest and cheapest solution is normally the 74HC165, especially if your MCU has an SPI interface.

mariush:
An option would be I/O expanders: https://www.digikey.com/products/en/integrated-circuits-ics/interface-i-o-expanders/749

60 i/o : CY8C9560A-24AXI https://www.digikey.com/product-detail/en/cypress-semiconductor-corp/CY8C9560A-24AXI/428-2017-ND/1640248

48 :
Diodes Incorporated PI4IOE5V96248ZLEX https://www.digikey.com/product-detail/en/diodes-incorporated/PI4IOE5V96248ZLEX/PI4IOE5V96248ZLEXDICT-ND/8548731

PCA9506DGG,518 https://www.digikey.com/product-detail/en/nxp-usa-inc/PCA9506DGG518/568-11940-6-ND/5221875

loads more with 28, 24, 16 etc

These are mostly i2c , super easy to use

some (for example the diodes inc one above) have an interrupt pin , so you can get an interrupt when one input changes instead of having to constantly read the state of all input pins. but you can do that also, whatever you like more.

HB9EVI:
+1 for the I/O expanders if I2C doesn't turn out to be too slow

dferyance:
It totally depends on your scenario but there are tricks to have multiple inputs go to the same pins. I've used different resistor values attached to switches and doing analog/digital conversion to know which ones are enabled. Keyboards often multiplex by enabling individual rows or columns in a scan loop. You might even be able to use common IC circuits like multiplexers or logic gates depending on your inputs.

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