Hi all, I have a system that I want to use for an airbed when I go camping. I have a 12V pump which i've cannibalised into a small enough housing to work and pump my airbed but it doesn't know when to stop....
So I'm thinking about building a little circuit to keep the bed at a certain pressure (PSI) and if it notices a drop then to activate the pump...
Any ideas what pressure sensor to use and how the circuit would work? (solenoids etc)
I'm subscribing to this. I would like to know about any cheap pressure transducers on the market as well.
Freescale MPX series. The MPX5100 gauge or differential sensor will work quite nicely for this. It can be interfaced straight to an Arduino analog input and powered from 5V.
You will need a relay or MOSFET to switch the pump.
Thanks for the input guys, I've found some AP2 pressure sensors lying around. I haven't had chance to get a capacitor which the datasheets says it needs yet but I will be connecting that up and trying to calculate and print a pressure in PSI on an LCD.
Only just realised I'll need a button to create a set point. Example: Program pumps bed to 3PSI > I lie on bed (pressure alters) so then I press the set button and it then uses that as a base point and if the pressure alters from that by a certain tolerance activate the pump?
For the pump I have a 10W 12V pump which I've got working nicely. (More than enough to do the job) The way i was going to connect the pump to the circuit was via a 180Ohm resistor and a PNP/NPN transistor (acting as a relay)?