Need help optimizing an LED design controlled by rotary switch

The rotary switch could be wired to turn on the LEDs directly - then all you need to do is sense switch position with the Arduino.

The rotary switch could be wired to turn on the LEDs directly - then all you need to do is sense switch position with the Arduino.

Douglas, that is looking like what I need as far as the order of the LEDs. Stupid question, but would switch position open=pin HIGH and switch position closed=pin LOW on the arduino in this case? Or do I have it backward?

If you put a pullup resistor on each cathode, then the pin with the lowest voltage is the selected pin.

This scheme would imply using 7 analog inputs. Note that some voltage dividers might be needed to keep the analog voltages in range of the Arduino.

Another method would be to use a dual gang rotary switch or a switch with 2 wipers, then the second switch could be setup for sensing position independent of the LED circuit. (a switch with 16 or 18 pins but only 7 or 8 positions)

There are several ways to connect the LEDs and the switch that would all work, depending on how many extra components you want to add, and what type of power supply you have available.

Understood thanks for the feedback. Overall im trying to minimize the number of components. I think I may have analog pins to spare, however using a dual wiper switch has advantages as well. Either way im going to need seven pins. Thanks for your help!

If you have an extra analog pin you could wire the second switch to output a voltage that indicates which position is selected - just put a series of 7 resistors between VCC and ground and wire the switch to tap into each junction. This whole system would only use one pin on the arduino.

Ill have to brush up on voltage sensing arduino, but I like that even better. Every pin counts since I am incorporating a proximity sensor, hid button and servos into this project as well. Eventually I want to design my own custom AVR board for this project with just the headers and connectors I need.

So, I did a little research last night to discover that 7-position two-deck switches are a little hard to come by. Is the pull-up resistor method the only way to accomplish this with a single level switch? Thanks

You could use the rotary switch with 7 resistors feeding a single analog input to indicate to the arduino which state is selected. Then you could de-multiplex 3 outputs from the arduino to implement the desired LED state.