It can be done through IO but unless you have some objection running the fan at half speed (or so) all the time is a much easier way to do it. If you are using muffin style fans you can put a resistor in series to accomplish that. For 12V fans a 30-100 ohm 1/2W resistor works good. Usually only a small amount of air across a heatsink is required for cooling so you can experiment with the proper speed. You could even use PTT to change the speed when you TX if you desire. I have not found that to be necessary.

If you can find surplus 24V fans they run great on 12V without a resistor.

73 Doug
WA3DSP
http://www.crompton.com/hamradio


Date: Sun, 3 Aug 2014 10:06:40 -0600
From: electricity440@gmail.com
To: app_rpt-users@ohnosec.org
Subject: [App_rpt-users] Simple I/O interface

Hi,

I have some cooling fans. 

I would like to have the fans turn ON when the radio transmits, and stay on for sixty seconds after the radio stops transmitting and then turn off. 

I would like to use the I/O interface on my URIx. (The I/O will then trigger a Solid State Relay ,and then turn on the Fans)

How can I do this with the software? Can I write it with Scripts?

 What commands would I need to detect if it is sending a PTT, detect PTT off, wait time, turn the output to high, turn the output to low, always "look" for a TX, etc.

Example code is always really nice for a beginner like me :-)

73

Skyler
KDØWHB

--

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