Arduino Forum

Using Arduino => LEDs and Multiplexing => Topic started by: Axinar on Aug 21, 2013, 06:12 pm

Title: more that 40 inputs
Post by: Axinar on Aug 21, 2013, 06:12 pm
hi,
i need something that is the oposite of the sift register. i want to measure if 40 pins are high or low using maximum 4 pins.
the frequency of the sample can be 1Hz or more! its not something that i need time aqurancy, i need just multply inputs!

thanks!
Title: Re: more that 40 inputs
Post by: robtillaart on Aug 21, 2013, 08:51 pm
have a look at the centipede shield - http://forum.arduino.cc/index.php?topic=7008.0 -

uses only 2 lines (I2C)
Title: Re: more that 40 inputs
Post by: CrossRoads on Aug 21, 2013, 08:57 pm
Use shift-in registers vs shift-out registers.
Latch the state of the parallel inputs, then clock the data in.
74HC597
http://www.digikey.com/product-detail/en/CD74HC597E/296-26011-5-ND/1507407