Quantity   Component name
2 × ICM7555 Clock and Timer ICs / Timer ICs
1 × LED blue 1 PPS LED
1 × LED red power LED
1 × R6 - 470 power LED resistor
1 × R1 - 1k common emitter base resistor
1 × R2 - 3k3 common emitter collector resistor
1 × R4 - 10k 1 PPS LED timer tau resistor
1 × R3 - 330 1 PPS LED timer output current limiter
1 × R5 - 220 1 PPS pulse stretcher tau resistor
2 × C3, C4 - 1 uF time tau capacitor
2 × C1, C2 - 100 nF timer decoupling capacitor
1 × DIN6 female Connector to MR350PS4
1 × DB9 (m or f) RS232 connector to computer
1 × DIN6 male pigtail Connector to computer keyboard input
1 × prototype board www.adafruit.com/products/1214