# I need a circuit where a single input triggers, 4 outputs in sequence?

Nov 11, 2018
1
Hi,

I'm hoping someone can help me, a my mind has gone blank, and I can't work out how to build this, or what it's even called! I have an automated rabbit hutch, and the last thing I want to build is a hay feeder for when I'm away. This consists of 4 boxes, each with a small door. When power is provided to an electronic solenoid holding each door closed, it opens allows the rabbits to access the assortment of food inside. I have a spare input controlled by my phone, which I can pulse on. What I want is a circuit which each time it receives an input, triggers one of the 4 outputs. Each time it triggers it rotates round. E.g.

First time it receives an input = output to open 1st door
Second time it receives an input = output to open 2nd door
Third time it receives an input = output to open 3rd door
Forth time it receives an input = output to open 4th door
Fifth time it receives an input = output to open 1st door
etc etc

Any ideas?

Oct 5, 2014
6,917
/n counter....

#### Harald Kapp

##### Moderator
Moderator
Nov 17, 2011
13,716
A 4017 counter is (almost) ideal for this purpose.
• Connect the pulse from the phone to the clock input (pin 14)
• Use outputs 0...3 (pins 3, 2, 4 and 7) to control the solenoids (by using suitable drive transistors in between).
• Connect output 4 (pin 10) to the reset input (pin 15). Thus the counter will count from 0...3 (4 states) and go back to 0 with the fifth pulse. You may have to add an additional reset circuit to ensure the 4017 starts with count=0 at power on.
• Connect clock inhibit (pin 13) to GND to enable the clock input.

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