Heatermetr Proofing Box Control

I'm building a bread proofing box and would like to use Heatermeter 4.2/ (RPi A+). I'm using the 12vdc output (for blower) as one of the outputs with a 1k resistor to an IR510 MOSFET to control 24vdc external power supply via relay. The relay controls a 110vac outlet connected to a small (2x2) frig. I inverted the output so when the temp is high, the output is on and turns on the frig. I planned on using the 5v output for the servo to control the other relay via a TIP120. This relay would control a 15w 110vac bulb to produce heat if the temp drops below the SP. The grounds are tied and am switching the low side (N Channel). The 12v MOSFET portion works fine however, I did not realize that the 5v (servo) power was constant (assumed it was switched). So the TIP120 is not going to work. I did notice that the signal output (servo) shifts between 142 and 155mv (OFF/ON respectively). My apologies I don't have a schematic to upload but its pretty straight forward. Is there an option I can use with that low a voltage or is there another output I can use? Or possibly control the constant 5v servo power via script? I'm not an electrical genius and fairly new to Heatermeter but spent quite a few years controlling industrial cooling logic. Any help would be greatly appreciated.

Yeah the servo power is a 5V constant and the servo signal is a 50Hz pulse width signal so what you're seeing is the average voltage, not a constant voltage. There's not really any output signal you can drive your TIP120 with unless you maybe hook up to an LED and set the LED trigger to something appropriate maybe?

I'm also not sure you want to hook the blower output to a relay controlling a refrigerator compressor because there's no short cycle prevention so it is going to be turning the compressor on and off at least once very 10 seconds.

Thanks Bryan- I was afraid you would say that. I can get around the once every 10 seconds issue (planned on putting a timer circuit in as well). I did notice that the "Invert Output" option for the blower doesn't seem to have an effect. I assumed since documentation stated it was for cooling it would be opposite of regular operation. Does this option work? The LED option might work. I didn't think of that. I was hoping to not get into the heatermeter too much though. Is the LED output 5v?

I think the LED route will work for what I'm after. I checked and the voltage at the LEDs when on is 1.9v and I can trigger the TIP120 at 1.2v. Anyone know what I need to do to merge these 2 scripts:

#!/bin/sh
# Silence this alarm, it will ring again if re-armed
al_set 0

-------------------------------------------------------
#!/bin/sh
# If no parameter, this is a regular alarm
if [ -z "$1" ] ; then
NOW=`date +%s`
# Set target for 1 hour from now 3600=seconds
WHEN=$((NOW+3600))

TARGET=`date -D "%s" -d $WHEN +"%M %H %d %m"`
echo "$TARGET * /usr/share/linkmeter/alarm-all RING${al_probe}" | crontab -

# make sure cron is started, it won't start if there is no crontab at boot
[ -z "$(pidof crond)" ] && /etc/init.d/cron start
else
# This is the cron callback
# Don't fire again
crontab -r

# Do whatever you want here, using another recipe
fi

First one is alarm off script and the second is time delay. I want to cut out the notification that the time delay script is doing and add the alarm off script in its place. My plan is to put this in the execute on alarm (probe low or high) after 3 minutes. Can anyone help me with this? Thanks

Actually disregard- I'm going to start a new thread in the appropriate category.