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Re: FS: Crashed Aircraft locator

hello and thanks for the information.

my unit weighs approx 12-14g ready to mount. they are using a smaller peizo buzzer in their system. these are cheaper buzzers that require a more complicated driving circuit. if you look up the specs on those type of buzzers you will see that they put out about identical dB of sound at the same voltages. you will notice that they are at a much higher frequency of audio which as we all know doesnt travel as far as lower frequencies do. my device is not incredibly fancy or feature packed but it does the job and does it well. my unit DOES work with PCM and also works with 6v systems unlike the one you use.

thanks for the great info.

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Reply to
Buckeyes1997
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I built similar devices for private use - first model used an inexpensive hef40106 hex inverter, and e few R/ C's - driving a smal piezo directly. Lots of noise, no fancy driving ckt's needed, even bridge driving possible.

Mowadays I use an AVRTINY15 8 pin cpu, even smaller, virtually no external components, and voltage check / RF hit counter included.

Not planning any sale - but bottom line is: get a look into these small cpu's!

Succes with building RC stuff!

Reply to
René

| my unit weighs approx 12-14g ready to mount.

Then you should put that on your web page. People care about weight.

You should also work out what the price is. Your post said $13, Paypal put them in at $14, and your club's web page said $15.

| they are using a smaller peizo buzzer in their system. these are cheaper | buzzers that require a more complicated driving circuit. if you look up the | specs on those type of buzzers you will see that they put out about | identical dB of sound at the same voltages.

Maybe the buzzer you're using is not as similar to the ones I've used from Radio Shack as I'm thinking it is ...

You could probably shave a few grams off by removing the buzzer case though.

| my unit DOES work with PCM and also works with 6v systems unlike the | one you use.

The Air Alert works at 6v too. The only problem there is that the low battery alarm goes off at 4v or so -- and by the time your 6v battery system reaches that voltage, you've got seconds left -- not minutes -- before your plane crashes. (Yours doesn't have a low battery alarm, so that's not an issue.)

And there's no way your system could work with the FMA M5 receivers that I'm using. The only reason that the Air Alerts do is that they plug into a live (i.e. in use) servo channel, and the alarm will go off if #1 the pulses to the servo stop, or #2 the servo doesn't move for a few minutes. #1 never happens with this receiver, even when the transmitter is off. Since yours doesn't actually watch the servo position at all (not if it's plugged into an unused servo), it can't do #2. (I had a lot of problems with this initially, because I'd gotten a different brand of lost plane alarm that worked like yours does.)

How do PCM receivers handle going into failsafe? When it activates, it sends the servo to the failsafe position (obviously), and then stops sending signals to it? That would explain how this sort of thing would work, but doesn't seem right, as the servo wouldn't even try to keep that position, beyond what friction does for it.

Ooh, maybe it's the unused servo thing -- being unused, it wouldn't have any failsafe information set, so it could be allowed to just float.

Reply to
Doug McLaren

okay the price error has been corrected and even lowered to 12.00 for a limited time. thanks everyone.

matt

Reply to
Buckeyes1997

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