New life for old pagers - siren alerting

aaknitt · Post by **aaknitt** » Wed Apr 12, 2006 8:45 am

Hi All,

I’m working on a project to add remote activation to our storm sirens in town, and I’m trying to do it on the cheap. We’re hoping to scrape up the money for a decent two-way system (probably Whelen), but in the mean time we want something to hold us over. During the last storm that went through the fire chief almost broke his arm opening a gate in the wind to manually set one of the sirens off. Not a happy camper.

What I’m planning on using is a couple of out of service Minitor IIIs. They’re still functional, but are out of service because the knobs are broken, etc. I’ve hacked the charging cradle to add another pin for the alert output. My first thought was to send the tones once to turn the sirens on and send them again to turn the sirens off, so I designed a latching flip-flop circuit to put on pager’s alert output. Then they changed the requirements and said they wanted a fancy “on-off-on-off-on-off” siren sequence. That was too much a pain in the butt to do with analog circuitry, so I switched gears and used a PIC to generate the timing sequence. Now they changed the requirements again and want a continuous three-minute “On”. Now I’m glad I switched to the PIC…no hardware changes, just software J

So now I have the Minitor alert output going to the PIC, which then activates a relay to turn on the sirens. When the tones are sent and the pager alerts, the siren will be “on” for three minutes and then turn off. If during those three minutes the tones are sent again the siren will shut off. The sirens are the really old mechanical type with no electronic control system…powered from 430VAC through a big relay.

I’m posting here to try to get opinions on whether this is a reasonable short-term solution. I don’t want to install anything that’s going to be unsafe. I know this system isn’t perfect, since it doesn’t provide feedback that the sirens have activated. However, my feeling is that something is better than nothing until we can secure funding to do a proper upgrade. Has anyone done anything similar? Any advice or recommendations? Failure modes that I haven’t thought of?

Thanks in advance,

Andy

Hoseman292 · Post by **Hoseman292** » Mon Apr 17, 2006 5:09 pm

Andy,

The Minitor pager part is the weakest link. You can pick up a Federal Signal Informer for ~ $400 with a built in relay and battery backup that would be solution to the problem.

http://www.federalwarningsystems.com/pr ... ?prodid=25

Another idea would be a GM300 which has programmable QCII and a relay output. Program your receive frequency and tone pair and use it as a tone alert receiver.

Tim

Asst17-1 · Post by **Asst17-1** » Thu Apr 20, 2006 8:27 am

We currently use a Minitor II to set off our siren and unlock the doors to the station. I purchased a Amplified Charger with the relay for $35 off ebay. Have had it hooked up for ~3 years now and haven't had any problems as of yet.

Cheap solution since we have 20 or so old M-II's laying around.

You can also buy a off the shelf timer that when it receives a input it will latch the output for the set amount of time. I also have the Amplified charger hooked to one of these that sets off a pair of Whelen TIR-3 lights mounted on each side of the bay doors. They flash for 4 minutes basically to give us an idea of response time.

My next project is to get the engine bay lights automated.

nmfire10 · Post by **nmfire10** » Thu Apr 20, 2006 10:32 am

You had no remote activation before. You have remote activation now. You've done something good. Sure, it isn't a $10,000 system but it will do the job until something bigger and fancier can be purchased. The alternative is getting killed trying to do it manually so I'd say go with it.

aaknitt · Post by **aaknitt** » Wed Jun 07, 2006 9:36 am

Well here's what I ended up with, in case anyone wants to make use of it.

http://radioetcetera.googlepages.com/re ... activation

Andy

MassFD · Post by **MassFD** » Wed Jun 07, 2006 11:48 am

Nice job with good documentation, thats more than we get from most of the big bucks manfacturers today. I have been doing all the odd ball things with pager alert outputs since the original Minitor, where you had to go inside to pick up the alert.

Have unlocked doors, disarmed alarm systems, started generators and did timed audio and station lights. It's limitless what can be done without spending alot of money.