I am looking for a photocell that turns on with light and off in dark. Is there such a thing or is there a switch to change this on any models you know of? Thanks, Bob

Don't think you will find such a thing. What you will have to do is use a relay. Run the light through the NC side and pick the relay with the photo cell.
When there is light the points will be closed and the light will burn. When there is no light the photo cell will pick the relay and the light will go out

Did that with a coffee pot one time.

Wow! Sounds like it will work but seems too technical for my small brain. Here's what I want to do. Engine oil pan heater for an aircraft, I live in a cold climate and I would like to rig a cheap cell phone that lights up to a unit so that I could place a call and activate the block heater on a one hour timer?? Is that possible and how would a layman go about it? Thanks! PS, what does NC stand for?

You mean you don't have a heated hanger!!

NC stands for "Normally Closed".

Relays are built differently. Some are built where the spring in them keeps a set of points closed. Energizing the coil opens the points and breaks the connection. Others are built with the points open (NO),Normally Open, no contact, and energizing the coil closes the points and makes a connection. Others relays are built with two sets of points, one normally open and one normally closed.

From what you described it appears that you are thinking the light from a cell phone would turn off a photo cell. Sorry but photo cells don't work that way. A photo cell does not react instantaneously. It takes about 3 to 5 minutes of light to break the connection across a photo cell and 3 to 5 minutes of the lack of light to make the connection. The small LED light of a cell phone would have no effect even if you could keep it on for 3 to 5 minutes. Just not enough light.

For what you describe, you could look into the Smart Home devices but I doubt that you have a phone line in the hanger.

You could try setting up a computer linked to you home computer and activated some timing device but again you would need a phone line unless the FBO has a open wireless network you could get into (if there is an FBO). Even if the FBO has an open network, if you are in a metal hanger you wouldn't be able to connect.

Who is paying for the lights, you or the FBO? Simplest thing would probably be to put your heater, which is hopefully thermostatically controlled, on a seven day programmable timer. Your plane needs to be flown at least once every seven days. You could even use one like you have for your furnace at home. Program it for the times you are most likely going to fly. Cost less than any automated system you can set up.

How about having the fuel man go around a flip a switch. I guess technology has not caught up with you yet, maybe some day.

What kind of plane?

Thanks, sounds like you might be a little familiar with airplanes? It is a 235 Cherokee. I like the idea of flying on a schedule but then work gets all mad at me... How about if I use a small toy train light activated switch, which operates instantly to light on or light off, but then use a relay to operate the heater? (Train switch has 110v relay but only capable of 2 amps or so )

Very helpful so far... Thanks

Also, regarding the quote:

"your heater, which is hopefully thermostatically controlled, on a seven day programable timer. Your plane needs to be flown at least once every seven days. You could even use one like you have for your furnace at home. Program it for the times you are most likely going to fly"


I'm trying to prevent heating and cooling cycles to keep condensation from forming.

If you have a Landline, you can call it up and turn it on for the timed 1 hour.
A scheduled timer will work as well as thermostat controlled?

Hoping you would pop in here Strat.
Unfortunately we apparently do not have a land line.

Bob,
If the train light photo cell reacts instantly and the phone light will activate it, you might be on to something. What turns train relay off? Wouldn't take much current to run timer motor. Almost nothing to run a digital timer.
Could use the train relay to pick a heavier latching relay. That relay starting a timer.

So, first question is will light from cell phone turn on train relay.

Got into flying a little bit years back with my neighbor, but I was more interested in working on the his home built Cozy.

Strat,
You are into this much more than I. If a land line will turn on timer, is there any possibility of using a cordless phone set with Bluetooth capabilities and doing the same thing. Cordless phone shouldn't know the difference between something coming in on the land line and something coming in on Bluetooth from cell phone.


What do we call this, Redneck engineering?

GSM REMOTE CONTROL SWITCH | CELL PHONE REMOTE CONTROL (http://www.gsm-auto.com/)

Can't get much better than that Strat.

I would be nice if it had terminals to have it make a call when contacts were opened or closed, and a Mike could allow listen-in.
Its perfect for this.

Solved! Thanks guys

Good Deal.
What did you end up with?

Going with the GMA unit but haven't figured out the carrier yet. Trac phone is best deal for 6 months use at a time and easy reactivate but not sure if I can use the sim card.

This device is perfect, I have thought about trying to market something like this because I was sure I wasn't the only one that needed it but now I don't have to!

Thanks again... Bob

Need any assistance with the necessary contactor and associated wiring?

I'm not sure yet but I will let you know. Thanks for the offer.

I just saw their plans, Personally I wouldn't have the load go through the internal switch. You could have a high current relay handle the current/heat, Contacts would last forever.
The 12 volt transformer could power the unit and the relay, the coil of the relay would be connected through the GSM switch.

Alarm Controls 3012 - HIGH CURRENT RELAY, 30 AMP. CONTACTS, SPDT, 12 VOLT AC/DC COIL. is made by Alarm Controls and is listed in our Catalog and Alarm Controls Corp (http://www.securitystoreusa.com/Alarm-Controls-3012-HIGH-CURRENT-RELAY-30-AMP-p/547355.htm)

More good info, Heater is 300 watt. Draws 2.75 amps according to the mfg.

Bakatronics - Model Railroad Electronics (http://www.bakatronics.com/shop/search.aspx?sfield=keywords&search=MX061)

Also found this online and have asked the company to build one with light activated and they think they can.

It Must get Cold EVERY night where you live. Other wise you would have it thermostatically controlled, not controlled by dark.
Intermatic make a Digital Timer with backup(loosing power won't disturb timing).
You could have it go on and off every other hour after dark, saving energy.
A photocell and relay is all you need.
You are going to need a photocell either way.