Didn't our own Bob WA1MIK write up such a kill device for his 900 machine not long ago at the Repeater-Builder site?
Maybe this: http://www.repeater-builder.com/motorola/msf/dtmf-ctrlr.html Why reinvent the wheel? Mark - N9WYS -----Original Message----- From: Repeater-Builder@yahoogroups.com On Behalf Of Mike Morris WA6ILQ Sent: Friday, April 17, 2009 1:00 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Remote receiver "suicide" control At 05:33 PM 04/16/09, you wrote: >Mike, Paul, Mike, Martin, and others... > >Thanks for the ideas. I will try out a couple of them and then make >a decision on exactly what method to go with. I had not thought of >using a latching relay. The lock-shut-through-its-own-contacts latching relay uses power as long as it is activated. As another gentleman pointed out, the magnetic latching relay only uses power when the coil is activated (i.e. a pulse to change the state of the relay). >The idea of a husky relay or maybe a beefy >SCR to short the supply on the inboard side of a fuse or circuit >breaker did occur to my feeble mind, but I wanted see what others >could come up with for ideas. The 12v circuit breaker with the shunt trip coil sounds like the most feasible, and besides it's designed exactly for the job. It beats buying fuses, and dropping a dead short (even momentary) across the battery is not going to do it any good. You could use an old IMTS horn honker decoder to trigger the trip coil. That was a box about the size of three thicknesses of Readers Digest that was a multidigit DTMF decoder that you programmed with either DIP switches or jumpers. You feed it +12 and receiver audio and it gives you dry relay contacts. When it decoded 7 digits it pulled in a relay that honked the vehicle horn and flashed the headlights. The bulldozer operator or whomever would hear the horn honk and go answer the mobile phone. The advantage of using a separate unit is that no matter what happens to the repeater controller a specific DTMF sequence on a specific receiver will kill the system. >Paul N1BUG Mike WA6ILQ
