Electronic Radio Circuits

  • Status Closed
  • Budget $30 - $250 USD
  • Total Bids 11

Project Description

I need 2 devices that are programmed to communicate via Radio signals. The idea is that the first device will transmit a digital radio signal to the 2nd device at the press of a button. The signal will only be heard and interpreted by the 2nd device. It must be able to transmit a clear signal to around 400 feet in the open. The 2nd device will always be monitoring for this signal. Upon receiving this unique signal, This 2nd device will in turn send a standard analog tone on an unlicensed radio frequency for about 6 or 7 seconds say. The signal should travel also around 400 feet at it's weakest point, but clearly receivable at 50-100 feet approx. The 1st device will also be equiped with a receiver tuned to this radio frequency in order to receive the tone or whatever noise it is really. It doesn't have to be audible. As it receives the tone, It will display a signal strength, either by LED, or more simply, via a Needle meter. In effect, the closer you are to the device, the stronger the signal. When you are within 50cm, the meter will read MAX. The 1st circuit should be built around components and battery small enough to fit into something the size of a C size Battery. The 2nd device should be built around components and battery that can be designed to fit into something about the thickness of a 3.5" Floppy disk and about 3/4 the length or smaller. The 2 devices will need to be based around cheap digital smd IC's that can be easily programmed to marry with each other. The programming will take place before the ic's are soldered, so no need to worry about circuit logistics. The analog radio signal can be a standard signal across the board. Only the digital signals will need to be programmed on an individual basis so as no 2 paired devices will be the same. I only need the circuit diagram, not PCB layout or anything else. As long as you keep in mind that the components used, when eventually designed around a PCB will fit into the desired size. The choice of battery type is important. They must be small enough to fit into the desired casing but powerful enough to last as long as 12 months on standby or as long as might be possible under the limitations. The 2nd device will always be monitoring for a signal, but needs to draw as little current as possible while doing so. It will then use a burst of current just for a few seconds while it transmits a radio signal. The 1st device will have a little more flexibilty as it can be much larger and maybe use common AAA batteries. the 2nd device might have to use powerful button batteries such 2 x CR2477T or something along those lines.

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