dual monostable circuit - remote humidity control

I'm wanting to build a remote switch to turn on/off my dehumidifier (or humidifier in winter) that is driven by a humidistat.

The humidistat opens/closes a switch based on the humidity level. I have a spare ceiling fan remote control (Harbor Breeze) that will work for the remote part. The problem I have is, I need to simulate the pressing of a button when the humidistat switch is closed, and then simulate the pressing of a button when the switch is open. With the fan remote, I can either use the same button (the one that powers on the light), or 2 different buttons (high fan speed, off). The light button will dim/brighten the light based on how long it is pressed, so I would be looking for a quick pulse if I use this button.

I have been told that I need to use a dual monostable circuit, aka “one-shot timer”. A coworker told me to get an Arduino controller, but I want to verify it will do what I need first.

Any suggestions ?

Is the remote infrared? If so, you can probably simulate it using the Arduino. If not, you could buy an extra remore, cut into it, and use relays or transistor switches to simulate the button presses.


The remote is RF (303.875MHz).

Will I be able to control the length of the pulse (pressing the button) with the arduino ?

It might be possible to find a compatible RF transmitter cheap (e.g., on ebay), but your best bet may be to just by a complete remote. If you don't want to cut into it, you could probably use something like a solenoid or servo to push the button mechanically. So you have multiple options in that area.

Controlling the pulse width is dead easy, and you have multiple options there, too. Check out the examples for flashing LEDs supplied with the Arduino IDE download, and in the "Playground" area of arduino.cc.


Thanks. I just ordered the Duemilanove, and I'll start brushing up on my C.