Reply to "The RR Track Signal Control Board Project"

And, if low-cost is the objective, I've posted OGR threads on how to use low-cost eBay relay modules to perform the timed-yellow delay.  Less than $5 per signal head.  No tedious component-level assembly/soldering if using $1-2 eBay relay modules (as opposed to wiring up a 555 IC timer chip). 

Again, No daisy-chaining capability, no clever bi-directional operation, no crossing-gate flashing, just basic drive-the-$4 3-aspect, 4-wire, common-anode LED signal head. 

For 3-aspect RYG:

For 3-aspect PRR in this case with a 25-cent roll-your-own optical occupancy detector instead of an ITAD.