Batboard

Hey guys. I have a bunch of Minitor II amplified chargers, however none of them have an accessory port on the back of them. Anyone know of another way to obtain a trigger out upon tone?

Thanks!

I'm not real familiar with those chargers, but you may be able to add a pin to the charger to contact with the alert output of the pager. Then you'd probably also have to add a transistor and a relay(example circuit at http://andyknitt.googlepages.com/firestationalerting).

The pinout of the Minitor II can be found at http://www.batlabs.com/minitor.html

For some ideas on how to add a pin to a charger base, take a look at http://andyknitt.googlepages.com/minitorprogrammer Like I said, I'm not sure if that same technique will work with the charger you have.

Andy

All of the amplified chargers have an alert light, which illuminates when the pager decodes a valid tone set. So the contact pin already exists, as does some type of circuit that turns the light on.

I can't say for sure but I would guess that all you need to do is hook a wire up to the right point in the charger and you're done.

WB2IID wrote:All of the amplified chargers have an alert light, which illuminates when the pager decodes a valid tone set. So the contact pin already exists, as does some type of circuit that turns the light on.

I can't say for sure but I would guess that all you need to do is hook a wire up to the right point in the charger and you're done.

Thats what I was guessing...I imagine I could see what triggers the alert light on the unit itself, and see if it would be enough for my application, however one of the nice things about the amplified charger with the accessory connector is that it can be set to automatically reset after a period of time. I imagine I could make something that would do the same with an IC chip, however at that point, it may be easier/cheaper for me to find someone with an amplified charger that has the accessory jack.

A simple "one-shot" circuit using a 555 timer IC will give you the timed auto reset functionality if you're comfortable with circuit building. Just search for "one shot circuit" or "555 one shot" and you'll find lots of schematics and tutorials.

Andy

"...I imagine I could see what triggers the alert light on the unit itself, and see if it would be enough for my application, however one of the nice things about the amplified charger with the accessory connector is that it can be set to automatically reset after a period of time."

The only thing that can be reset is the circuit within the charger itself; the pager needs either a finger to push the reset switch, or be configured for auto-reset operation. Pin 6 on the pager/charger interface goes HIGH for the length of time the pager beeps, and seems like that could be used to drive a relay.

Or, like you said, find one that has the acc connector already on it. Probably on ebay.

[quote="WB2IID"]"...Pin 6 on the pager/charger interface goes HIGH for the length of time the pager beeps, and seems like that could be used to drive a relay. [quote]

So could I wire in a pin to the bottom of the drop in charger (non amplified) that would come in contact with pin 6 on the bottom of the pager?

If so...which pin is which on the bottom of the Minitor II's?

Thanks!

I have a Minitor 2 non-amp charger with the alert light on it. I just tapped into the alert LED power to drive a solid state relay. Works great. Now I have people at my station asking me to build them one but now I can't find the relays I used. (bought them at radiohack, now they don't carry them.)

ffexpCP wrote:I have a Minitor 2 non-amp charger with the alert light on it. I just tapped into the alert LED power to drive a solid state relay.

However then I would also still need a timed relay for this to work...and it would only work once, then have to be reset.

Anyone know more about if I tap into a pin on the bottom of the pager if this applies a signal out upon alert?

The alert output on the pager goes "high" whenever the pager is alerting (beeping). It stays high for the duration of the alert, and then goes back low. So if you want something to turn on for one minute, you could program the pager to have a fixed alert length of one minute, etc.

Hope that helps!

Andy

EOppegaard wrote:Hey guys. I have a bunch of Minitor II amplified chargers, however none of them have an accessory port on the back of them. Anyone know of another way to obtain a trigger out upon tone?

Thanks!

Eric, I found the Service Manual for the NRN4986 Minitor II amplified charger With or Without Relay option. It looks like the Non-Relay Model has the same Control Board as the Relay Model. The Relay Model has the relay a couple transistors, resistors & diodes. The Audio Board is the Same except the Non-Relay Model doesn't have the Din Connector installed. PM me if you still need the info. I can scan the Schematic and Parts list for you. Mark

FYI: The 6pin DIN connector is as follows.
Remote Spkr: Pins 1 audio high & Pin 6 ground
Relay Dry Contact Closure: Pins 2 & 3 (10 watts @ 28 volts)
Relay Closure Timing:
Pins 4 & 5 Open Relay closed for 10 secs. after alert.
Pins 4 & 5 Shorted Relay closed until reset button is pressed.