what im trying to do is set up a pick to light operation for my production line. currently im looking at using the arduino mega and some leds, relay boards and ldrs to make this. for starters this is going to be a 8 bin setup so there is not going to be any barcode reader or anything fancy. just basicaly repeat the process over and over again. in the future that may become need on some of my other production lines but this is a start. the problem im running into is that im a noob with the arduino period. im not sure on what the programming would consist of. the wiring i think will be the easy part since i can use the relay boards to switch back and forth between red and green leds for the eight bins.
So... you need to control 16 LEDs (8 Red and 8 Green). What, exactly, do you want the lights to do? I am not familiar with the term "Pick-to-Light".
yes 8 red and 8 green.
pick to light
basicaly it tells the operator what part to pick and what time in the process. that way everybody that does that process does it the same. what im looking for is each bin will have a red and green led. the red lights will stay on unless that is the bin that is need to be pick from. the bin that needs to be picked from will turn off the red light and turn on the green light. the ldr will sense there hand reaching in to pick the part and then switch the green light off and turn the red light back on and then continue to the next bin that needs to be pick and so on
To read 8 LDR inputs you need either an Arduino with 8 analog inputs (Arduino Leonardo, for example) or an analog multiplexer (CD4051, for example). The multiplexer needs 4 pin, three for address and one analog input pin.
An Arduino UNO/Arduino Leonardo only has 20 digital I/O pins (of which 6/12 can also do analog input). It is usually best NOT to use pins 0 and 1 of the UNO for anything other than serial I/O. With four pins going to an analog multiplexer that leaves only 14 pins for your 16 LEDs. You can use shift registers to control all 16 LEDs with 3 pins: