Preheat remote switching
A bit of history 1st: Here in western new york we have to do a lot of preheating.
For the 11 years I have been flying my Series 5, I have had to drive to the hangar either the day before a flight to set the timer, or the day of the flight to plug in the preheat. For several years I have been trying to figure out a way to turn on the preheat from home. The hangar is a country setup on a grass strip with no WIFI so computer control was out , leaving a phone activation as the only solution. There are several ready to go units produced , but they are pricey from $225 to $300. Being the cheapo that I am, I couldn't bring myself to spend that money so I kept looking. I finally found a reasonably priced solution- but it takes a bit of homebuilding to accomplish.
After a lot of searching on the internet , I found a guy from Romania who builds reasonably priced , phone activated relay switches for different applications. I purchased his ET-30 model for $25.00 which included shipping. His ebay name is electronic1tricks and if you use this link ,www.youtube.com/user/electronic1tricks/videos , he has some great videos on how his switches work. You may have to hunt and peck a bit as several videos come up on this link, just look for ones with the electronic1tricks name attached.
Using the ET-30 as the heart of my system, I used an old cellphone (has to be dedicated to this purpose) as my activator for the ET-30 switch. The activation is actually done by a light sensor on the switch that "sees" the cell phone light when it is called. I have mine set up to activate after 2 consecutive calls, to eliminate activation by a solicitor or mistaken caller (this is an option you set up when you get your switch). If you have a phone that can restrict incoming calls , you could have it activate after one call.
Now to the homebuilt part-when you get the switch , it is simply the circuitboard with the relay and some wiring terminals. I went to the local home depot for parts which included a gray PVC elec box to hold everything, a 15 amp typical household outlet and 6 feet of 12/3 cord to wire the unit. (I used 12/3 but 14/3 should be sufficient and easier to fit to the switch terminals . You get directions with the switch so the wiring part is pretty easy. I have included a picture of my setup. You can see in the photo, that the 6 foot (black 12 gauge) power cord gets me from the hangar outlet to my box , then I plug my preheater extension cord(yellow 12 gauge) into my gray box outlet. Also note you will need a phone charger always plugged in as the phone is always on, and though the photo shows a 9v battery as my relay switch power supply, I have a 12vdc wall plug on order to supply power.
I have flown on 3 consecutive days and the system has worked great. I get up check duats and if it looks good, call the preheater (2 times) and it turns on. when I get to the hangar 2 hours later I am good to go. I have been shutting the unit off at the hangar when I get there, but if I decide not to go, another 2 calls from home will shut it off.
Costs : ET-30 switch $25 , phone sim card for old phone plus 3 months of minutes -$21 (basically 3 bucks a month for prepaid minutes on t mobile) at most $25 for home depot stuff for a total of about 70 bucks. Any questions drop me a line. Sorry its so long winded , hope you Desertfox guys didn't read all this caus you won't need it! Bruce N199CL
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Originally Posted by GregA
