It is the essential continuity of circuits Sel 8 Sources and Up/Down Sel 8 Sources, but can work and autonomously, collaborating with any suitable circuit of control. The Relay 1-8 can be 6-24v DC. For current of collector of transistors Q1-8, bigger the 10 mA, it is better we use BD 139 or BD 679 with R 1-8 is 15K?.
R1-8=4.7 Kohms T1-8= BD139 (R1-8=15 Kohms if T1-8=BD679)
RL1-8=6V-24V dc Relay D1-8=1N4148