Help with a wireless relay control modification circuit

[HalloweenBob]

I will start by describing the problem, then I will propose my solution. I hope that someone here can first, tell me if my idea would work, and secondly, help me find what I would need to put it together.

The problem:

I have purchased a simple 12 channel remote relay system for about $20.00. It is a hand held transmitter with an antenna that works at 315MHz. The receiver is a board with 12 relays on it, one for each button on the transmitter. It all works. If you push button #3 on the transmitter, Relay #3 closes. The same with all the other buttons. This is not latching. It is in momentary mode, as I need it to be. Each relay will stay closed for as long as the button is being held down. As soon as the button is released, the relay opens again. What I need for it to do is to allow me to press and hold down a given button. Let's say button #3. While still holding that button down and keeping relay #3 energized, I want to also press and hold Button #4. I want relay #3 to remain energized since button #3 is still depressed. I also want relay #4 to become energized at the same time because I am pressing down Button #4 as well, and so on. Unfortunately, it does not work that way. If any one button is pushed, pushing any other additional button at the same time does nothing. Apparently, it is only capable of transmitting a single button closure at a time. I need no restrictions on the number of buttons pushed.

What I am using it for:

Instead of just pushing the buttons on the transmitter, I have wired 2 joysticks and a couple of extra buttons all mounted on a panel to the switches on the transmitter. Moving the joysticks controls 2 large mechanical arms that can move up and down and out to the side and back. These actions must be able to happen at the same time requiring up to 6 connections to be needed simultaneously if I am moving both arms and pushing a couple of the buttons at the same time which would be quite likely. The relays control coils in pneumatic valves which control cylinders that move the arms. The motion is dampened so it is not very fast moving.

My Proposed solution:

On the panel which I have built with the joysticks and the buttons, I add a circuit board that does the following:

1. scans all my switches multiple times a second to see how many connections are being made at any given time and which connections they are

2. Give me an output that will send a sequence of quick 'pulses' to close the switches on the transmitter one at a time, rapidly scrolling through all the switches that are currently closed on the panel until the state changes. As an example, If I am holding my joysticks in a manner which would cause buttons #3, #4 and #5 to all be closed at the same time, I would want this new circuit to close switch #3 for a few milliseconds then release it, then close switch #4 for a few milliseconds, then release it, then close switch #5 for a few milliseconds, then release it, then go back to close switch #3 again and continue that rotation until its scan of my panel determines that a different combination of switches are now closed and adjust its output accordingly.

The result of this would be that the transmitter would only be transmitting a single closure at a time, but they would be so rapid that the end result of appearing to move two or more pneumatic pistons at the same time would result.

The timing of the scanning and how long each output is held on before moving to the next would need to be adjustable in case the transmitter and receiver can't communicate as quickly as the information is moving. It also needs to stay on long enough for the physical relay to actually close and start to activate the coil of the valve before it goes off.

I can see a problem where the relays and valves wear out prematurely because now instead of closing the relay and valve once for 5 seconds, the relay and valve have actually been cycled many times in that same time span. If we slow this down to only dividing each second up into 5 parts, much longer durations than one might initially program for, this might be a good compromise. If each step in the 'Rotation' of the output stayed closed for 200 milliseconds, it would mean that if 4 switches were closed at the same time, it would cycle through all of them and hit the first one a second time all within a second, which would be less wear and tear on the relays and valves and would still probably look like smooth enough motion at the output. This is all for visual effect. It does not have to be precision at all. The fewer switches being held down at a time, the quicker it more pulses per second each relay gets.

I hope I have explained what I need adequately and that someone out there can help me. Please feel free to ask questions.

I can buy a transmitter/receiver combination that will do this, but it will cost between $600 and $800! I hope this would be a cheap, simple solution to this problem and might be helpful to others in a similar situation as myself.

[pebe]

I think that pressing a button modulates your transmitter with a signal from a tone generating IC. The receiver would use a similar IC to decode the tone into 1 of 12 outputs.

It can only generate one tone at a time, so you would need to change the transmission to a repeated train of pulse, as used in radio controlled models. Each pulse in the sequence would then be, say, 1ms for a switch off and 2ms for a switch on. Can you identify the IC used for the tone generation?

[casdsys]

From memory, the output odf the relays are determined by how the receiver is programmed to respond to the transmitter.from memeory if you press the learn button on the RX whilst pressing the button 3 on the TX, the RX relays will activate as long as you have the buttons on the transmitter pressed.

Learn / program the RX the pressing the button number 9 on the TX. This will give you altrernating relays outputs.
i.e. press 1 to turn on then press 1 again to turn off.