Problem with flexinol air valve driver circuit

Let's Make Robots
1

flexinolValve_Arduino_5V_ProMini.jpg (57164Bytes)

Hello,

I'm trying to interface a flexinol air valve  https://www.robotshop.com/media/files/pdf/electrostem-2-valve.pdf with a 5V Arduino Pro Mini https://www.arduino.cc/en/Main/ArduinoBoardProMini and IRFZ44N N-Channel MOSFET http://pdf.datasheetcatalog.com/datasheet/philips/IRFZ44N_1.pdf

The attached schematic is not working.  R1 - 1KΩ; R2 - 10KΩ; R3 - 5.6Ω/5W

==

Valve characteristic:

Operating voltage: MIn. 1.6V ON/ Max. 5V

Current draw: 0.8 - 2.5A

Resistance: 1.3 Ω

PDM frequency: < 5kHz

Flow rate: 3.0 ft3 / min (typical)

Response time: < 0.2 sec ON/OFF

==

Testing condition: at room pressure i.e. 1-5psi

==


Any suggestion will be much appreciated.

s.

2

Reading the datasheet you

Reading the datasheet you linked for the valve it says the included electronics module limits the current through the valve protecting it so you may not need the 5.6R resistor if that is true. And further down it intimates that 0 - 5V generates a proportionate gas flow. Do you get ANY air flow?

I would remove the power resistor or if you are worried about burning it out reduce it to half or stick another same in parallel to test.