Gas Fireplace Controller
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Use your smart phone with a Wemo Switch to turn your gas fireplace on and off.
(not for fireplaces with a wall switch)
11/23/15 Update...
After using this circuit sucessfully for almost one year, I discovered that the capacitors need to be a higher capacitance to allow a longer 5V pulse to turn on the fireplace. Evidently, the fireplace valve becomes harder to open with age.
The original 2200 uf capacitors sent a 3 second pulse to the fireplace valve.
I think it needs to be more like 5 seconds.
Therefore, my simple solution was to use two 2200 uf capacitors in parallel
which should give you about a 6 second pulse.
(the original design used just one capacitor to open and one to close)
It works well in my tests.
You also need to reduce the resistors to 750 ohms to allow the capacitors to discharge more quickly
(which I did by putting two 1.5 k resistors in parallel)
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12/13/14
I recently purchased a Cedar Ridge fireplace log set from Lowes. Model CRHED24RT
It is a 24" ventless gas fireplace insert that can work with natural gas or Propane.
The fireplace works great but the remote control has lots of problems.
I tried two different remote controls and receivers. Both had problems turning the fireplace on and off (just would not respond intermittently).
So, I gave up on the remote and designed a solution myself that lets me use my iPhone to turn the fireplace on.
I use a Belkin Wemo switch and the Wemo app on my iPhone.
Build one yourself
But
First a Note of CAUTION!
This project requires prior experience building electronics circuits (Soldering skills and basic knowledge of electronics design).
It goes without saying that this procedure could void your warranty. Proceed at your own risk.
The Cedar Ridge fireplace has a wireless receiver box that plugs into the fireplace with a two-pin molex connector.
You will remove the wireless receiver. It will not be used. Instead, you will connect the output of this project into that connector.
FYI: You can easily see how the wireless receiver works by putting a meter on the two molex pins. It is powered by 4 AA batteries and has an on/off switch. When you turn the switch on, you will see +6 volts for three seconds. When you turn it off, you will see -6 volts for 3 seconds. (assuming that it has new fully charged batteries).
I don't know why it thinks it needs to stay on for 3 seconds. That just makes the batteries wear down sooner. It really only takes a fraction of a second to trigger a latch solenoid.
Since we are removing the wireless receiver, we will no longer need to worry about batteries because no batteries will be used.
We are using a 5 volt power supply in this project but you can use 6 volts if you wish.
An added bonus for using the Wemo switch is that it works with IFTTT. I have a Nest Termostat that also works with IFTTT. That lets me set up a rule in the IFTTT iPhone app that tells the Wemo switch to turn off the fireplace when the thermostat temperature rises to a pre-determined level.
How it Works
When the Wemo switch turns on, it sends 115 volts to the 12 volt power supply which turns on the relay.
The relay is a double pole, double throw relay. One pole has +5 Volts DC and the other pole is the negative side of the 5 volt power supply.
When the relay turns on, a capacitor charges and releases a +5 volt pulse to the fireplace solenoid to turn it on.
When the relay turns off, another capacitor charges and releases a -5 volt pulse to the fireplace solenoid to turn if off.
The Circuit and Components
REFERENCES
Wemo Communities (User Forum)
http://community.wemothat.com
Belkin Wemo Switch at Home Depot
http://www.homedepot.com/p/Belkin-WeMo-Switch-F7C027fc/203536127
Belkin Wemo Web Page
http://www.belkin.com/us/Products/home-automation/c/wemo-home-automation/
Cedar Ridge Fireplace at Lowes
http://www.lowes.com/pd_574328-51507-CRHED24RT_0__?productId=50291839&Ntt=
(Or you can find inexpensive reconditioned fireplaces on Amazon. Just search for CRHED24RT )
IFTTT (If this then that)
https://ifttt.com
Nest Learning Thermostat
https://nest.com/thermostat/life-with-nest-thermostat/
Rich Love
Project Design
richlove@carnationsoftware.com