10 signals thru 2 cables

[andrew2022]

what i need is a circuit in 2 parts. 1 is to have 10 inputs and convert them into 2, the second is to receive the 2 imputd and convert them back into 10 outputs. any1 have a diagram for this or know how it can be done?

 

[panic mode]

If I understand correctly, you are looking for a way to transfer
10 signal using one pair of wires (not 2 cables!). There are
different way to multiplex signals (like Holtek chips) but first
tell us a bit more and post the specs.
You can also try to use resistor ladder (each switch turns on
different resistor) and ADC.

 

[andrew2022]

yes, u understand correctly. basically i have a power supply supplying 12VDC. the positive can be run to the location seperatly. at this side there are 10 switches which are to be connected tot he transmitter card. the transmitter card is to then send a signal to the receiver triggering a relay (up to 5 switches will be on at any 1 time)

 

[panic mode]

Any reason to use realys? (isolation? different voltage?)

 

[andrew2022]

some do have to be relays (to switch a higher voltage) altho most dont (they will be signals to another circuit)

 

[Nigel Goodwin]

There are many ways it could be done, you could use PIC's at either end (but everyone knew I'd suggest that ).

The Holtek encoder/decoder chips could be used as well, and are actually cheaper than PIC's.

But the switched resistor method "panic attack" mentioned is probably as good as any other (and has often been used in commercial products). With this you don't need any supply to the transmitter end, just a ground and signal wire - the receiver end feeds power through a resistor down the signal wire. The switches at the transmitter simply switch different value resistors down to the ground wire, changing the voltage on the signal wire.

Rather than using an A2D, you could use an LM3914, which would give you the required 10 outputs, and have reasonable drive capacity.

 

[gerty]

If you use the LM3914 don't forget to figure in your cable resistance :lol:

 

[Nigel Goodwin]

If you use the LM3914 don't forget to figure in your cable resistance :lol:

That applies to any resistive A2D method, some of the very old JVC based VCR's used a cable remote control that worked in this way. Unfortunately it was very poorly designed, with the buttons allocated badly, when the cable started to get a bit poor they often defaulted to record when you pressed various buttons - which was often quite troublesome. I replaced the leads on a great many of them over the years.