Posts: 1
Joined: Thu Sep 17, 2015 12:09 am

flow meter for raspberry Pints kegerator

Thu Sep 17, 2015 12:21 am

Hi guys,
My first post here, I'm trying to put together the "RaspberryPints" keg meter system and have a query about a flow meter that i have purchased to do the job with.
Its a GEMS FT-110 ... low-Sensor
It states it requires a pull up resistor of R=1- 2.2KOHM and the output is a square wave signal. not sure on this bit?
This is where the design comes from. I'm not very confident on this bit with the connecting of the flow meters and would really like some assistance if someone can help me out.


Posts: 7120
Joined: Sat Aug 18, 2012 1:21 am
Location: New Zealand

Re: flow meter for raspberry Pints kegerator

Thu Sep 17, 2015 1:46 am

It seems to me that you need to connect the meter as follows:
Power pin -> Pi 5V
GND -> Pi 0V
Signal -> Pi GPIO (choose one)

The output is open collector, which means it will pull down to ground when activated and "let go" when not. That's why you need a pull-up resistor. However, you should connect the pull-up from the device output to Pi 3.3V (not 5V).

"Square wave" output basically means the output is either on or off, not a varying value somewhere in between.
Hmm. What can I put here?

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