(1 digit 7 segment display) One digit per wire.

Hey guys this is my first post and i'm a noobie.

I want to create a gear indicator. My goal is to have 7 input wires total. So, one wire per gear.

wire 1 - ground -----
wire 2 - 1st gear ----- ( displays = 1 {b,c} )
wire 3 - 2nd gear ----- ( displays = 2 {a,b,g,e,d} )
wire 4 - 3rd gear ----- ( displays = 3 {a,b,c,d,g})
wire 5 - 4th gear ----- ( displays = 4 {f,b,g,c})
wire 6 - 5th gear ----- ( displays = 5 {a,f,g,c,d})
wire 7 - 6th gear ----- ( displays = 6 {a,f,g,c,d,e})
wire 8 - neutral ----- ( displays = the dot on the corner {DP})

so essentially i would only need 1 wire (plus ground) to display a single digit.

I want this to be as compact and small as possible and i was wondering if theres a way i could do this without using the ardruino board and only using some type of microcontroller. If so, how do i even begin to make this?

You can do this with just diodes, and resistors for each segment.

wire 2 - 1st gear ----- ( displays = 1 {b,c} ) 2 diodes
wire 3 - 2nd gear ----- ( displays = 2 {a,b,g,e,d} ) 5 diodes

etc.

Similar to this (depending on switch polarity, things may have to be reversed).

gnsampayan:
I want this to be as compact and small as possible and i was wondering if there's a way I could do this without using the Arduino board and only using some type of microcontroller.

As larryd explains, use diodes. :grinning:

But if you did need a microcontroller for some other project, "only using some type of microcontroller" and "without using the Arduino board" is not very sensible. You use a Pro Mini - all necessary components provided and eminently compact. (Any smaller and you will have trouble soldering it!)

You probably can use an EEPROM as a lookup-table.

Indeed you could, but the 28C16 mentioned is a peculiar bird; specified for TTL rather than CMOS logic levels.

So you would need an octal buffer chip of some sort for the LED display and some input protection diodes and resistors for the EEPROM.

By the time you wire up all that, the diodes are probably easier!

But I have ordered a few 28C16 to play with anyway.