Hi Guys,
I'm new to this so please excuse what is probably a very basic query! I have tried searching first but couldn't find what I'm looking for (I may not have used the best search terms so feel free to direct me to a relevant previous thread if there is one).
I want to design a circuit to provide a remote indication of the setting of a 3-position switch, ie. there will be a switch with positions 1,2 and 3 on one unit, connected by a cable to another unit some distance away which will have 3 LEDs, with only one lit at a time depending on the switch position. There is an obvious solution of simply using 4 bus lines (gnd, 1, 2 and 3) however I want to minimise the number of cores required in the cable (to two if possible), and also allow for a 'failure' mode whereby if the connecting cable is disconnected or cut, a specified one of the LEDs will illuminate, rather than them all going out. I'm imagining something along the lines of a polarity based system with current in one direction illuminating LED1, the reverse direction LED2, and no current at all LED3. In this case, LED3 would also be the 'failure' indicator. What do I need to realize this at the LED end though? Power will be batteries, and will be available at both ends of the system.
Any pointers please?
I'm new to this so please excuse what is probably a very basic query! I have tried searching first but couldn't find what I'm looking for (I may not have used the best search terms so feel free to direct me to a relevant previous thread if there is one).
I want to design a circuit to provide a remote indication of the setting of a 3-position switch, ie. there will be a switch with positions 1,2 and 3 on one unit, connected by a cable to another unit some distance away which will have 3 LEDs, with only one lit at a time depending on the switch position. There is an obvious solution of simply using 4 bus lines (gnd, 1, 2 and 3) however I want to minimise the number of cores required in the cable (to two if possible), and also allow for a 'failure' mode whereby if the connecting cable is disconnected or cut, a specified one of the LEDs will illuminate, rather than them all going out. I'm imagining something along the lines of a polarity based system with current in one direction illuminating LED1, the reverse direction LED2, and no current at all LED3. In this case, LED3 would also be the 'failure' indicator. What do I need to realize this at the LED end though? Power will be batteries, and will be available at both ends of the system.
Any pointers please?