PDA

View Full Version : Preheat remote switching



airlina
12-23-2014, 04:44 PM
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

PropellerHead
12-23-2014, 04:53 PM
Awesome!

You realize that you have just been added to some DHS watch list for buying a cell phone activated relay from Romania right? :-)

airlina
12-23-2014, 05:37 PM
Funny you mention that, I was gonna reference what my contraption looked like, but figured I'd be ramp checked by customs and border protection on my next flight- so lets just call it the preheat actuation device and leave it at that. Bruce

TahoeTim
12-23-2014, 07:39 PM
Or www.switchboxcontrol.com

I own one. Reiff makes one too.

jrevens
12-23-2014, 08:08 PM
That's cool - it would make a nice clean unit for very little money. I notice the 4 relays are rated at 3 amps each. Can they be triggered simultaneously (if you wanted to parallel them)? If you use this set-up, do you use an additional relay for switching your heater PropellerHead? The combined 12 amps might be marginal for many heaters. What kind of battery & how long does it last (I assume you might use a power supply).

n85ae
12-23-2014, 08:27 PM
Thanks a lot Bruce, now my entire family is probably under NSA surveillance
since we've exchanged emails over the years. That thing looks like it's
right out of a movie ...

:)

My solution, - I leave mine turned on all the time, with the thermostat set
on low and the heat output on low as well. Keeps my engine warm to the
touch, and the electric bills low enough that the airport manager doesn't
complain ...

Jeff

DesertFox4
12-23-2014, 08:57 PM
hope you Desertfox guys didn't read all this caus you won't need it! Bruce N199CL

We Desertfox people would love to have a remote preheat system. My 912S is very cold blooded at 50 degrees F or below. Trouble is Bruce, I'd lose my hangar immediately if caught with anything plugged in while unattended. Against the rules and all that you know.:rolleyes:
You guys with private hangars got it made all over me.

Great thread guys with lots of good info.

GregA
12-23-2014, 09:56 PM
One I built a few years ago using a similar setup:

http://www.vansairforce.com/community/showthread.php?t=38729&highlight=switch

Greg

Paul Z
12-23-2014, 10:20 PM
I got picking through the Vans link and found this very nice switch design.

http://www.rvplane.com/?categoryid=10000&dayid=1005

Oops update, this one doesn't fall Ito the inexpensive category, $180 for the switch.

airlina
12-24-2014, 04:18 AM
One I built a few years ago using a similar setup:

http://www.vansairforce.com/community/showthread.php?t=38729&highlight=switch

Greg

Greg, Nice setup there-very similar to mine. I wired my relay switch to a 15 amp outlet so I could plug in my extension cord to the preheater . I also thought about putting the cellphone in the box, but wasn't sure how strong my signal strength in the hangar would be so thats why its on the outside. T mobile prepaid plan is $10 for 3 months or $3.33/mo. After 3 mos you have to recharge the minutes for another $10 which I probably will do to get me thru May (yes around here we need preheat for 6 mos.) My rule is preheat below 40 deg OAT-makes for a happy engine and easy startup . And Jeff H. sorry for making you an accomplice . Bruce N199CL

TahoeTim
12-24-2014, 05:14 AM
The link I posted to the switchbox I own has two outputs that are fired through a text message. I can start a battery tender or my Tanis engine system. On a day I am flying, I text it when I wake up. By the time I have breakfast and drive over to the airport it is ready to go. I don't leave my battery tender on constantly but I will run it from time to time for a few hours.

I understand going cheap but I didn't see much difference when it's all said and done and I have a reliable unit with a remote antenna option to get a good signal outside the hanger walls. Besides, my doesn't look like it was assembled by a terrorist :D