Wireless DTMF controlled remote relay ideas

[Frosty]

This is the solution: www.nhrc.net/nhrc-remote-plus/    Now I just need to define the problems for it to solve   :)

I got a couple ideas, like using it to activate a gate/garage door opener or to turn on outdoor lighting from our mobiles or HTs, but I'm trying to think of more SHTF-tactical uses for it.  There's cheaper ways to open a garage door for sure, but this is just too  8)  to let pass without further discussion.

We'll be a small group, spread out at 3 (or maybe 4) different sites in a 30 acre area, with maybe only 12v power available at each site.  I'm thinking of putting a HT and the NHRC  decoder/relay in weather-proof boxes with a solar 12v battery backed power supply as the control portion.  With that HT set on our tactical freq and PL tone, we could coordinate our plan via voice, and anyone in the group can activate a relay without needing to switch to a different channel.  The freq and PL tone, plus the 4-digit DTMF password, should provide reasonable security against anyone else activating our relays.

Trying to think outside the box for what kind of remotely activated devices would give a tactical edge in a SHTF situation for static defense in about a 1/4 mile sq (very rural) area.  Horn/siren?  Electric match and smoke producing devices?  Activate a winch?  Along those lines anyway.  Nothing illegal or dangerous, directly.  Any ideas or thoughts, tactical or otherwise?  Or maybe it's better to ask, how is this likely to fail just when I need it to work?

[Rob_ma]

I don't have direct experience with that particular board but I have used NHRC repeater controllers before and the quality of their products are very high. I have constructed similar setups to activate notification horns for lightning alerts.

Keep the battery voltage up and make sure your audio levels are set correctly so that the DTMF tones get decoded EVERY time they are sent. There is a handy LED on the board that flashes upon proper DTMF decoding. Check DTMF decoding using a weak signal as well. Other than that it sounds like a terrific remote control system.


- Rob

[KK0G]

Nothing illegal or dangerous? Damn, and I had all kinds of cool ideas  8)

My first concern with this idea would be power consumption. I don't know what the current draw is but it will be on and drawing power 24/7, could be pretty significant long term.

Another concern I would have is non-technical, inexperienced users in the group. Keeping it on the same frequency as your voice communications would be an advantage there.

[Rob_ma]

The description for the remote control board states:

The NHRC Intelligent Remote draws about 14mA @13.8V with the LEDs disabled making it ideal for solar powered applications.

So it won't add a lot to your power budget.

[KK0G]

The description for the remote control board states:

The NHRC Intelligent Remote draws about 14mA @13.8V with the LEDs disabled making it ideal for solar powered applications.

So it won't add a lot to your power budget.

Yep, that's pretty low all right.

[RadioRay]

well - remotely turning lights on/off,  opening gates,  turning the coffee pot ON.  Starting your car remotely (good for Mafia types)...


>Ray

[Frosty]

I have constructed similar setups to activate notification horns for lightning alerts.

A car horn was my first thought, that would make a great burglar deterrent if a Dakota Alert went off.  Hey, wait a minute...   Hi Rob!  Fancy meeting you here.  Those two used MATs I got late last year are still working fine.   Any thoughts on modifying/reprogramming a MAT to transmit DTMF tones?  Or even better, adding a relay to the MAT itself?

Nothing illegal or dangerous? Damn, and I had all kinds of cool ideas  8)

PM me your thoughts KK0G, want to make sure I didn't miss anything :)

Starting your car remotely (good for Mafia types)...

Reminded me of a joke from All in the Family, Archie doing a crossword puzzle.  "A four letter Italian word for 'goodbye'.  Bang.   B-A-N-G."

The lack of AC power at the sites really limits the options, and at 12V the device to activate is going to have to be close to the HT/decoder or the voltage drop would be too much.   

[Rob_ma]

A car horn was my first thought, that would make a great burglar deterrent if a Dakota Alert went off.  Hey, wait a minute...   Hi Rob!  Fancy meeting you here.  Those two used MATs I got late last year are still working fine.   Any thoughts on modifying/reprogramming a MAT to transmit DTMF tones?  Or even better, adding a relay to the MAT itself?

Howdy! :)

When the passive infrared module is tripped there are two wires connected to a terminal strip inside the MAT that power the transmitter. It is marked TRANS +/- and is the two left contacts. You could use that signal to power a relay. It will only be active during the time you hear the voice alert (about 7-10 seconds) and is not a latching output.

By the way the MATs can be powered with 12 VDC so if you are using a 12 volt battery you can power everything off the same battery. The two right terminal contacts are marked INPUT +/- and that is for the power input.

- Rob

[Frosty]

Thanks Rob.

At 8.7v in, the voltage across the transmitter is about 7v when activated.  If the ratio remains the same using 12v in, should have about 10v across TRANS +/-.  Think I'm going to head to the auto parts store and pick up a couple SPDT relays and see if that's enough to power the 12v coil in them.  Highjacking my own thread here, but a car horn on the relay would make a great burglar alarm for everyday use in the outbuildings, plus no more low battery alerts at 3am with a battery and solar panel.

And should the SHTF, I'm putting the Looters, MZB's, and any other would be Evil-doers on notice here and now. 

You do NOT want to mess with Frosty's stuff.

Mwahhahahaaa!

[Rob_ma]

Don't know if this helps you or not but here is the schematic for the MAT.

- Rob

[Frosty]

Thanks Rob, have one that the motion detector portion seems to work OK but it won't xmit.  Maybe I can figure out why now.  Been awhile since I played "goes inta  / goes outta" with a piece of electronics and a schematic though.   :-\

I spent half of Sunday playing with a spare MAT.   The roughly 10.5 volts (using a 12v supply) dropped across TRANS +/- is enough to activate a standard 12v automotive relay.  I tested the relay operation when the transmitter trips using a automotive bulb.   Works.  Secured the relay inside the housing, wired it and the power for the MAT, and added an on/off switch.  Need  to add a fuse, and caulk the hole where the wires protrude still.   Think I'm going to add a relay to all my MATs since they don't interfere with the operation, even if unused.   Just need a 5W solar panel and a couple hours of spare time to get it all set-up in the polebarn.

Meet the working prototype of "MATthew".