What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Cellphone remote switch

Greg Arehart

Well Known Member
Here's what I've been doing when I can't do any test flying....

A couple weeks ago I posted a request here regarding build-your-own remote cellphone-operated switch to turn on my engine heaters remotely. I finished putting this together tonight. Total cost about $50 as follows:

$11 - 4 x 6 x 6 plastic junction box from Home Depot (includes a sealable waterproof lid!)
$18 - Apogee kit (http://www.apogeekits.com/remote_control_via_cell_phone.htm) including shipping
$10 - cheap walmart cellphone, comes with 10 minutes (good for 30 days)
$20 - optional additional minutes, good for 90 days



This photo shows the wiring inlet - standard electrical fixture (I got a waterproof one, but unless this is outside, waterproof is probably not necessary)



This is the assembled kit, which I screwed to the bottom of the box with 4 screws in the corners of the board.



Closer view of the board. Ignore the orange piece of tape - it shouldn't be there. Large blue box is the relay - rated at 15 A 110 V so should handle most any engine pan heater and/or cylinder heaters (my setup totals 500 W). 110V wires are connected to the common and NO (normally open) points. Red thing is the potentiometer to adjust the sensitivity of the photocell. Photocell is the little thing sticking up from LDR1. It can be bent to whatever orientation is necessary. DC power for the board is on the right (SK2) - I used an old power supply from a telephone or something, but make sure it is 12V and not something else. The board comes with a plug for the "standard" 12V circular plug, but I wired mine direct because of space considerations. Everything else is just put on the board per the instructions in the kit.



This is the same view with a small shelf I manufactured out of scrap Al (lots of that left around the shop!). The photocell is in the center below the hole. I will just put my cell phone on the shelf and hold it down with a couple rubber bands. The key is to make sure you get a phone that lights up CONTINUOUSLY when you call it, and place the screen so it faces the photocell. Adjust the sensitivity so the light from the cellphone triggers the relay consistently. Mine is set to high sensitivity because there is no other light that can enter the box so I am not worried about extraneous triggers. By the way, there are two modes on the circuit board. Mode one is where a single call switches the relay on for a preset amount of time up to an hour. Mode two requires two calls (in close succession) to the phone to switch it on, and it stays on until a third call is made, which switches it off. The small USB-style plug in this photo is cell phone power.

Other notes. I just took some RTV and glued the two transformers (one for the circuit board, second for the cell phone) into the corners of the box. I soldered pigtails onto the plugs for these transformers to make them easy to wire (see figure 2 above). For the power cords, I just cut an old extension cord in half.

All in all, a pretty easy and cheap way to remotely turn on my heater! The only drawback is the cell minutes. Since I never answer the phone, I don't use any minutes, but they expire after a certain time, so I'll have to get more minutes next winter. I am hoping I can find a better/cheaper deal on minutes than the $20 cards that I see.

If anyone needs more details, feel free to PM me (I will be out of town all next week, however).

cheers,
greg
 
Last edited:
Wow, we both basically did the same project in the last week, but I used a different board. I picked up an 8 channel DTMF controller from NHRC. This one uses the phone DTMF codes to turn up to 8 things on/off and has password protection and transmits an acknowledgment in morse code...
http://www.nhrc.net/nhrc-remote-plus/

I set it up with two relays, one channel for the preheat and another for the battery charger. Sure saves driving out to the field and waiting for a couple of hours!
 
...This one uses the phone DTMF codes to turn up to 8 things on/off ...

... and it works? Reason I ask, is that cell phone audio is a highly compressed digital stream, which has difficulty transmitting audible DTMF... or at least that is my understanding.
 
Here's what I've been doing when I can't do any test flying....

Large blue box is the relay - rated at 15 A 110 V so should handle most any engine pan heater and/or cylinder heaters (my setup totals 500 W). 110V wires are connected to the common and NO (normally open) points. cheers,
greg

Greg,

I did essentially the same thing you did, with one difference that might be important. While the relay on the board is rated for 110V, the circuit board runs are not. The circuit board is indeed rated at a max of 24V and is marked as such.

The solution is to use a simple external relay. I ran a jumper wire from the power pin to one of the NO pins on the board, then used this to power the coil to an external control relay ($7). Might not be an issue, but electrically 110V is not kosher for the circuit board on the kit you are using. (read fire + hanger = :mad:)

BTW, I am using the dip switches set up where call it twice to turn on, and once to turn off. I have been using it for a few months now and it works well. Just put your phone on the do not call list so that a junk call does not turn off your preheat.
 
Last edited:
Dale,

The board itself is powered by 12V and the relay is isolated from the rest of the board and is designed for switching 110V. My electrical guy in my lab tells me that it should not be an issue - and the Apogee folks clearly show it turning on and off lights, so I am not too worried. Never hurts to have an extra layer of protection, however.

cheers,
greg
 
Cell phone remote

Greg, I built the same Velleman kit that you built and put the additional relay to handle the current of the heater and put it out at the hanger. It worked when I put it out there, but wouldn't work when needed. I did some research and one of the two IC's quits working at 32 degrees f. I see you live in NV. so you might be OK, but here in Michigan it doesn't work a good part of the winter. I also tried putting one of those heaters they put in gun safes to keep condensation from forming in the box but it doesn't put out enough heat. So as long as the temp in your hange is above freezing you will be OK.

Mike T
 
Greg, I built the same Velleman kit that you built and put the additional relay to handle the current of the heater and put it out at the hanger. It worked when I put it out there, but wouldn't work when needed. I did some research and one of the two IC's quits working at 32 degrees f. I see you live in NV. so you might be OK, but here in Michigan it doesn't work a good part of the winter. I also tried putting one of those heaters they put in gun safes to keep condensation from forming in the box but it doesn't put out enough heat. So as long as the temp in your hange is above freezing you will be OK.

Mike T

Perhaps some heat wrap tape like that used to keep pipes from freezing??
 
Mike,

Correct, the circuits quit working around freezing (I also found out by experience since I didn't read that in the instructions). I wired two christmas-type light bulbs into the circuit so that they are continuously on, and the heat from these has been sufficient to keep the board working fine down to at least 10 or 15-degree nights (I haven't checked on colder nights). The bulbs are inside the box and wrapped in Al foil to keep any light from disturbing the photo eye. I used two bulbs on the assumption that one would fail eventually and I would then still have at least one heat source. You could do similarly but use three or four bulbs, or that heat tape. Insulating the box would also help.

cheers,
greg
 
I purchased a device which takes a cell-phone SIM card and has relays built onto it to control my sump heater. It is great because I can send it a text message, and it will reply with an acknowledgment. And it works quite well in sub-freezing environments. A T-Mobile pre-paid SIM card costs about $10 every 3 months to keep it active.

DSCN1648.JPG



Full Details are at: http://www.rvplane.com/?categoryid=10000&dayid=1005

Total cost was around $250
 
Last edited:
I built something very similar from the product supplied by www.gsm-auto.com.

The built-in relays (2) are rated for 250v and are heavy duty enough to control my 1500w heater. You can either set it up to respond to just the phone ringing from a particular phone, or it will respond to and reply back with text messages. I love it!

Although the GSM-Auto controller is more expensive ($179) it does come already pre-assembled with 250v relays in its own enclosure. You just have to add a 12v transformer (+-$10) and the GSM SIM card. I'll post pictures if anyone is interested.

T-Mobile has the best pay-as-you-go plan that I found for this type of device. It's $10 and the $10 is good for 90 days. I just bought a cheap pay-as-you-go phone from the local CVS drug store for under $20 and used the SIM card out of it in the GSM-Auto box.
 
Do you guys make IED's in your spare time too?!?! This is weirding me out!!! (But pretty cool stuff)
 
Details

Would love to see the details, I will be in the same boat, 30 minute drive to the airport. It would be great to start a heater before I get there.

Mike

I built something very similar from the product supplied by www.gsm-auto.com.

The built-in relays (2) are rated for 250v and are heavy duty enough to control my 1500w heater. You can either set it up to respond to just the phone ringing from a particular phone, or it will respond to and reply back with text messages. I love it!

Although the GSM-Auto controller is more expensive ($179) it does come already pre-assembled with 250v relays in its own enclosure. You just have to add a 12v transformer (+-$10) and the GSM SIM card. I'll post pictures if anyone is interested.

T-Mobile has the best pay-as-you-go plan that I found for this type of device. It's $10 and the $10 is good for 90 days. I just bought a cheap pay-as-you-go phone from the local CVS drug store for under $20 and used the SIM card out of it in the GSM-Auto box.
 
RE:Great Info

I would love to build one of these....My only problem is as an old, slow, retired chemistry teacher I need plans/instructions/parts lists/pictures.....plus a lot of ear time to answer my questions?

Steve and Greg you are really giving me some ideas. Now if I can just decided on the style. The phone/text style seems like it really covers the bases.


If you guy's have pix/detailed info I sure would like to see them.

Have I mentioned I just love VAF..........

Frank @ 1L8 ... RV7A ...
 
Last edited:
Frank,

The Apogee kit came with instructions and it is a fairly simple electronic job (electronics are NOT my specialty by any means). And it was cheap. Key is if you are in a really cold area to add the small light bulbs (wrapped in foil to cut the light) to keep the box warm enough to allow the electronics to operate properly.

Thumbnails in the first post are links to larger images.

cheers,
greg
 
I have been using the GSM-AUTO setup for a couple of weeks now. Was pretty easy to put together and works better than I ever expected. Send a text to turn it on and a few hours later show up at the hangar to a warm engine.

A few hints to other users:

1. Most cell phones have quick text feature that you can add the commands and when you want to turn it on, check status, or turn it off just select the quick text that you have pre entered instead of having to type the whole command each time.

2. When you get to the hangar and want to shut the realy off, instead of sending a text and receiving a confirmation text, just unplug the gsm-auto and the relay will reset off when plugged back in. This will save a little $.
 
Cellphones and airliners

Do you guys make IED's in your spare time too?!?! This is weirding me out!!! (But pretty cool stuff)

Now we get to the real reason they want those portable electronic devices turned off!..What is that guy packing into the hold?
 
Can the GSM remote be controlled via an Internet text message?

I installed a GSM-AUTO remote relay in my hanger today. It works great. I am wondering if any of you more experienced users have identified any internet based text service providers that would allow the switch to be controlled from a computer.

I tried several, but all seemed to append some junk to the coded instructions which causes the GSM unit to reject the message. I am using an AT&T sim card.

Thanks,
 
question

As I understand it a photocell is a form of a variable resistor, so the board "knows" about the presence of light by sensing a specific voltage. Could you possibly eliminate a possible failure mode by just direct wiring the ringer/vibrate with a resistor in parallel or in place of the photocell? Basically the ring/vibe of the phone sets it off?
 
Good question Dean. I guess the only downfall of using something online is you wouldn't receive the confirmation text.

I have the GSM-RELAY by www.waferstar.com. (bought off ebay). It seams to be about the same as the GSM-AUTO unit.

I had originally thought I would only text it, but it's a lot easier just to call. I have my cell in the whitelist so it'll only take calls from me. It rings twice and immediately goes to voicemail. This turns on my hangar heat for 30 minutes. I love it!

Something else pretty cool. The power has been out all over the place lately. (snow storm with freezing rain). I figured my hangar probably didn't have power either so instead of driving up there I just texted a status check. Sure enough no reply. The cool part is when the power did come back on 6 hours later, I received a reply to my status check.
 
I installed a GSM-AUTO remote relay in my hanger today. It works great. I am wondering if any of you more experienced users have identified any internet based text service providers that would allow the switch to be controlled from a computer.

I tried several, but all seemed to append some junk to the coded instructions which causes the GSM unit to reject the message. I am using an AT&T sim card.

I'm currently working on an internet-based switch that would work similar to the cell switch, but uses direct internet connection (presuming you have such at your hangar). There is a little relay switch that can be programmed to run a bigger relay (enough to handle the electric heater current). I'll post when I get it tested, probably in a couple weeks. This eliminates having to pay a cell phone bill every month - just requires an old computer to be on in the hangar and you can control from home.

Greg
 
Greg, Can you design it for multiple hangars? Sure would be cool if one person in the hangar row had a computer, and we could all turn on our heaters remotely. I'd think it would be a low voltage line strung to the addition hangars controlling a relay in each hanger. What do you think? Thx, Jim
 
Question for Jeff about WHITELIST

"I had originally thought I would only text it, but it's a lot easier just to call. I have my cell in the whitelist so it'll only take calls from me. It rings twice and immediately goes to voicemail. This turns on my hangar heat for 30 minutes. I love it!" End Quote

I've been looking for an app like the'whitelist' you mention. I only see this sort of thing available for land lines.

Roger Bloomfield
Buena Vista, co
RV-9
RV-8 Painted
 
Roger, I haven't heard of an app for that but it seems reasonable. The whitelist in the GSM-RELAY is integral to the box and is programmed with a PC or by text.
 
Jim,

Possible. My current plan will connect to the internet via wireless (there is a guy down the row who has a wireless broadband router, so we all get internet from him). I actually will use the wireless connection going to my old laptop, which will just sit in the corner of the hangar quietly humming away until I take control of it remotely from home. Then it's a simple matter of running a tiny program that flips the remote switch to turn on the power. I suppose I could wire up several remote switches, each with their own program, but it would be just as simple to set up several computers, one in each hangar.

Greg
 
I am resurrecting this old thread as I research solutions for turning on my engine heater from home. It looks like technology has changed since this thread was originally posted and this switch from Amazon looks like a good, cost effective alternative to buying one of the kits from apogee.com or the UPhoneIt sold by Aircraft Spruce.

I was hoping one of you electronic geniuses would take a look at this and let me know if you see any reason that this would not be a good solution to starting an engine heater from home. I would think that the biggest concern would be the amperage rating of the relays, but it looks like these are rated at 30A each, which should be plenty.

Thanks for the help.

gsm_controller_500.jpg
 
I use this unit to turn on my engine heater and hanger heat. (It has 2 channels) I operate it with a T-Mobile SIM card. It was a bit of a pain to set up (due to T-Mobile customer service). Once it was set up, however, it worked great and has done so for 3 seasons. I add $10 to the SIM card once a year just to keep it active.
 
I decided to buy this GSM switch from Amazon to allow me to remotely turn on my engine heater. The directions are pretty weak and I'm not real strong with electrical things. I was wondering if one of you guys could back me up on the wiring of this switch?

I bought the AC version vice the D.C. Version, so it take 115V AC power in. I plan to use the male end of an old orange 16 ga extension cord for power in.
1. Do I just attach the white and black wires to spots 1 & 2?
2. What do I do with the green wire (ground)?

For the output, I'm using the female end off of relay #1. The same questions apply here. White and black off of 6 & 8? What do I do with green?

Here's a link to the manual for the 12VDC version. There is no manual for the AC version: http://tinyurl.com/z3tds57

Manufacturer's website: http://tinyurl.com/js6jag5

IMG_0028_zps49k9dy5r.jpg


IMG_0029_zpsauscmmnp.jpg


Thanks,
Chuck
 
Caveat Emptor

I'm no electrician, but have done my fair share of home wiring while setting up my shop. The following comes with no guarantees, or warranties.

1. Do I just attach the white and black wires to spots 1 & 2?

Yes. Some people think it matters which you connect where, and for DC this is absolutely true. For AC however, I have never understood the reasoning. I can't see in the documentation which pin (1 or 2) connects to the relays. I will assume that one of the pins connects to the common (C) of the relays and the other to the NO and NC terminals. Just try and keep it consistent throughout.


2. What do I do with the green wire (ground)?

I would connect the green wires from the input and the output together. Inside the box, if there's room.

For the output, I'm using the female end off of relay #1. The same questions apply here. White and black off of 6 & 8? What do I do with green?

This looks correct. Again, if you can verify the connections between the common and power pins, try and keep them consistent from input to output.

Good luck!
 
I'd hire an electrician

From the sketch, it looks like pins 1 & 2 provide power only to the components on the circuit board, not to the relay contacts.

Each relay switches common (C) to one of the other 2 associated contacts (NO or NC) depending on the command you send. If you connect your AC wires to pins 6 & 8 and send the command to connect them, the relay will connect the black wire to the white wire. Briefly. I would hire an electrician for peace of mind.

(Also, T-Mobile and its re-sellers will be your only choice for a SIM card. AT&T is turning off all its GSM service at the end of the month.)

Bo
 
I Stand Corrected

From the sketch, it looks like pins 1 & 2 provide power only to the components on the circuit board, not to the relay contacts.

Each relay switches common (C) to one of the other 2 associated contacts (NO or NC) depending on the command you send. If you connect your AC wires to pins 6 & 8 and send the command to connect them, the relay will connect the black wire to the white wire. Briefly. I would hire an electrician for peace of mind.

Excellent observation Bo. I would agree with your assessment.
 
Schematic

Forgive the crude schematic. I don't have my usual schematic tools here at the office. I think what you want is something like below. The "Z" is your AC load (heater, etc.).

5UMO1CyLV2CXXkvYosrwnHce3JCKjM6rK2KdIGg0zKQDD5BRpfRueK8YbXCJUstc5Po8uv-eR7RPplFudle_VqjlsBt--b1QfxWR_bzBm7AHTRfRxqzOaWAc_FCsaZmQ9ZEmeBCgJU5myisGl_f9oh8CAmJ-xRS6vPI2JcdW6zvTV11IRgjh-1oov7w_QVKMEKeIb50uL_DVHQ1T1QMcPMoHD22gQDPwm3DZJr3QoJB90tA4wIsCJQfv08hD4ORZEZCmxUxwD4iJlBSc5aWSIard0sOrbIB5nGkXQXwJwBwAzNGdcwUgIa23SlM-Nc8RrI_cd6wSens9AVbanHl5jua-_TtrAmB4KwE1A7poOYbI0jR3eeD2jdrNvXMniNS7mDojHOo7a3X5R3lbSAObj4K35mV1SzUhq_w701t05KXaHECxA2qdyE-PBq-APbYOA21Ybausc-TAyww8v4vdFcRfGwmBjHcc7dWjiqVZbV2WU2CBvsZcpl3MvReh_yIUaPqEkL5hFcQwSIHwcVw6FefR9m1LZ7W98ygkfd8Vt5cwgkDV6lZl88do765c1vE22GYgaZ9_Lh7GIgqmCGgElrbkEnsXVOJwiRfBBNk-cMJFY2dDgRWP=w474-h299-no
 
Last edited:
I decided to buy this GSM switch from Amazon to allow me to remotely turn on my engine heater. The directions are pretty weak and I'm not real strong with electrical things. I was wondering if one of you guys could back me up on the wiring of this switch?

IMG_0028_zps49k9dy5r.jpg

I have an older AC version of the same unit that I wired up. The following assumes that your model is the same wiring (the manual link seems to indicate it is). There is no internal connection between the 1 & 2 terminals and either of the relays, the 1 & 2 terminals are simply to power the board's electronics. The relays are separate from the internal electronics.

Needless to say, if you're uncomfortable working with household power, don't try this at home.

Your incoming and outgoing power cords should all have three wires:
Green: ground
White: neutral
Black: hot

Connect all of the greens together; they don't need a connection to any of the terminals.

Put a white pigtail on terminal 1, connect this and all the IN/OUT whites together.

Put black pigtails on 2, 3, and 6, and connect all three to the INCOMING black.

Connect one OUTGOING black to 8; this is your first switched circuit.

Connect one OUTGOING black to 4; this is your second switched circuit.

No connections to 5 or 7.

Here's a sketch of my connections (click for bigger):
 
Thanks for the help guys. Here is another diagram from the 12VDC manual:
Screen%20Shot%202016-12-14%20at%209.21.07%20AM_zpstniblrfl.png


I will have an electrician look at it, but I also want to learn as I go.

I finally found this project. I guess that I didn't realize that terminals 1&2 are just to power the device, not provide power to the heater.

JWyatt,
I sincerely appreciate your diagram. That helps a lot. One question... Yours shows that we use 3&4 and 6&8, but the diagram above indicates that I should use 3&5 and 6&7. Thoughts?
 
I sincerely appreciate your diagram. That helps a lot. One question... Yours shows that we use 3&4 and 6&8, but the diagram above indicates that I should use 3&5 and 6&7. Thoughts?

The choice of which pairs to use sets up the desired operation of the device:

Connect heater between C and NC (normally closed) if you want the power to be ON to the output when the relay is deactivated, and the power to turn OFF when you activate the relay. The relay opens the circuit when activated.

Connect heater between C and NO (normally open) if you want the power to be OFF to the output when the relay is deactivated, and the power to turn ON when you activate the relay. The relay closes the circuit when activated.

For our remote heater activations, we want to connect in the second manner (turn heat on when activated). I also see that the NO vs NC terminals are swapped on the second diagram you posted, so you should verify the actual setup of your device, too. It's the NO vs NC (terminal function) that matters, not the specific terminal number.
 
Last edited:
if this solution is already posted , sorry.
a 5 watt night lite bulb is enough in one of those thick styrofoam containers like labs use to transport blood. i put my light on a thermostat.
hdwe store has ''inline'' thermostats for electric baseboard heaters . you can figure out the rest.
 
Me too?

My neighbor already has Internet and a wireless router in his hangar so he spent $44.00 for his smartphone compatible remote switch. Here is the link:http://www.belkin.com/us/p/P-F7C029/

What is required for me to use my neighbor's internet for this type of switch? I currently use it now to stream music with my iPhone when I'm at my hangar. It is not password protected...would I need his IP address or somethin'?
I guess I'm confused about how I would "call", or contact a WeMo switch with my iPhone.

I feel like such a grandpa...
 
What is required for me to use my neighbor's internet for this type of switch? I currently use it now to stream music with my iPhone when I'm at my hangar. It is not password protected...would I need his IP address or somethin'?
I guess I'm confused about how I would "call", or contact a WeMo switch with my iPhone.

I feel like such a grandpa...

Grandpa, it's internet magic. Once you purchase the WeMo follow the simple instructions. Do you have a smart phone? You will download the wemo app to your phone (or tablet) take the plug to the hangar and have it plugged in in-range of the wifi and two steps later it will all be in sync. Your hangar neighbor need not know. Nice...
 
PFM

Grandpa, it's internet magic. Once you purchase the WeMo follow the simple instructions. Do you have a smart phone? You will download the wemo app to your phone (or tablet) take the plug to the hangar and have it plugged in in-range of the wifi and two steps later it will all be in sync. Your hangar neighbor need not know. Nice...

I'm reminded of the question I posted last year asking about my Dynon autopilot installation; "..if I splice my roll servo into the wires of my pitch servo, how does it know where to send the input ?..."

Answer; Magic!

Obviously, I'm a visual learner, and when I can't 'see' the electrons, or ones & zeros, my brain starts smokin'.

I'm off to Walmart for a WeMo!!
 
Back
Top