So how do I do this ?

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n9gik
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So how do I do this ?

Post by n9gik » Tue Feb 13, 2007 12:44 am

I have a private well house I am responsible for. I would like to set up a a radio that is tied in to sensors that called me when the temperature fell below a preset number, water pressure drops, power fails, or some other event triggers an alarm.

I'm thinking an HT with a quarter wave antenna on the roof for the radio side of things. I'd want some kind of processor that when a sensor closed (or opened as the case may be) a circuit the processor would key the mic input and play a recorded message, then unkey and repeat after a preset time.

It shouldn't be that hard to come up with all this, but it would be nice if I could do it fairly inexpensively. Probably would want a gel cell instead of a ni-cad for longer battery life.

Any ideas?
I don't know much about 2-way radios but I'm over 50 and can't remember not having one around. Everything from Buddy and Citi-fone to Icom and Kenwood.

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ohgary
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Post by ohgary » Tue Feb 13, 2007 7:19 am

A little basic stamp would do it. Send a message in morse code waiit, resend.

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Re: So how do I do this ?

Post by Two way repair man » Fri Feb 16, 2007 9:37 pm

You are asking to for a lot to happen at a low cost. Are you wanting someone to develop this gadget for you or are you going to do all of the research and development? There are low power data transceivers that might do the trick but I do not know of any cheap throw together systems for what you want.

In case you are going to try to develop this device, here are my thoughts: As suggested by ohgary, the Parallex Basic stamp probably would be the microprocessor board that could do the trick. You will need to be familiar with Basic programming and you will need to design some other circuitry. Also, you would need to purchase the programming cable. The programming software is free and works with almost any version of Windows.

Are the sensors already in place? If not that is going to be even more money.

Are you scared yet?

I hope this helps you decide if your idea is a sick fantasy or a worthy challenge.

Regards,

Bill

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n9gik
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I think I am over engineering things

Post by n9gik » Sat Feb 17, 2007 3:05 am

I posted this on an ag machinery forum (see the thread at http://u15205752.onlinehome-server.com/ ... 66#M103866)
and after a few questions and responses posted this:
OK, budget and more details ... I would hate to put more than another $50 in it. But I already have many of the components on hand.

I have a couple Kenwood HT's available, so the radio side is taken care of. Distance is about 2 miles either way to a base radio, so that should work no problem. I was thinking of using a gel cell (ie "Panansonic" videocamera battery) and a wall wart to keep it charged. I have those.

So basically I'm looking for a controller to plug into the external mic input to key it up and transmit a message. Morse code would work. Voice would be nice because anyone hearing it would know what it was telling them, but code would be enough to get their attention to start looking.

Now that I think about what I REALLY have to have, maybe I'm making this too hard. My main concern is the light bulbs (in the well house to keep it above freezing) going out and not knowing it. So all I would need would be a photoconductive solar cell tied into a morse ID'er and the TX circuit on the HT. So when the lights went out it would key up and transmit a message. This would also function as a power failure indicator.

I would probably want to incorporate some kind of timer, like 15-30 seconds on, 3-5 minutes off, so it didn't totally tie up the frequency and give longer battery life. Because you know it will go off about 11 PM and nobody will be near the radio until 5 the next morning. And come to think of it, I believe I have a photocell in the chicken house (my walk in junk box collection) that was designed to activate a light.
So maybe all I need to do is find a simple CW ID and start digging in my junk box.
I don't know much about 2-way radios but I'm over 50 and can't remember not having one around. Everything from Buddy and Citi-fone to Icom and Kenwood.

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Re: I think I am over engineering things

Post by Two way repair man » Sat Feb 17, 2007 2:42 pm

Now we are getting to the details that matter. Forget the Basic microprocessor board because it is out of your price range once you add up everything else.

Your idea to utilize the CWIDer for keying the radio would be the most simple to use. The sensors would have to trip a relay or FET transistor that would supply voltage to the CWIDer board. I would suggest that you use a separate transistor or relay for each sensor.

You will not get the fancy voice telling you that the pressure is low, or the bulb is out, or whatever else, but you should get notified if something goes wrong. If you use a different CWID board for each sensor with a different CWID, that could alert you as too what function has gone bad.

Also, have you considered the distance from your planned antenna location versus the location of the radio, the CWID board, and your sensors? If the antenna is too close to the board or the sensors you may need to isolate them by putting the board in a metal box and using shielded cable between the sensors, board and the radio. Or, you might need to relocate the antenna. If the coax from the portable to the antenna is too long you might not be able to get away with poorly shielded RG58 or RG8X without causing RFI. If the SWR is too high you might not get the range of 2 miles and the transmitter will probably have a meltdown problem. But then how many times do you expect problems?

Is there anything in this well house that might cause EMI like pump motors, or generators, or florescent lighting?

I am just thinking ahead for all of the potential problems you might encounter and hope it helps.

Regards,


Bill

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Post by kd6kml » Wed Mar 21, 2007 4:54 pm

I have used Link-Comm RLC1 controllers to monitor the operation of generators. Gives voice responses, can send quick call, and ID your telemetry station. They have both digital and analog inputs and outputs.

Get an old Minitor pager or Plectron and use Quick Call to notify you of problems.

Maybe there is another ham repeater controller that can be used that is cheaper, but I haven't found one yet that is as versatile as the RLC1 for this kind of stuff.

Josh K6ZRX
Always watch the fat man,
For he has found the easy way.

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