MrDEB
Well-Known Member
The circuit is a pinewood derby starting tree. 1 blue light for staging, 3 yellow lights flash in sequence, a green light comes on after the last yellow
The 555/4017 are configured as a count to N and halt. The 555 output is enabled/disabled using the 2n3904 (Q1)
The uln2804 is a darlington array, allows interfacing to higher voltages (outside world, 12v dc)
The outputs of the 4017 are ORed using diodes D1-D4 which control the output of the 4030 exclusive OR gate
The output of the 4030 turns on or off the 2n3906 transistor which enables the relays RLY2 & RLY 3. If a yellow light is on then the Q2 transistor is on thus allowing a single red light if “driver” pushes the release button ( N O monetary pushbuttons connected to J-3.
Relays rly2 & 3 are configured to allow ONLY one red light, A first and only “ situation.
Relays rly 1 & 4 control the 24v dc solenoids and activate rly 2 & 3 if a red light is supposed to come on.
J2-pcb is connected to the solenoids thus isolating the 24v dc from any ground connections from the solenoids etc. No chance of ground loops etc. feeding back into 12v dc circuitry.
Had that happen ??
I tried using a mosfet as well as a triac (have lots of leftover from xmas computer display) couldn’t get either to work??
The relays were easier etc.
In spare time I kinda learned this pcb123 program. Pretty easy once you get the hang of it.
Decided to just f4 fun design a pc board for start tree
The proto-type is a real wiring mess. Cut wires trying different things, several unused transistors etc.
A real chance of a wire coming loose and disabling the circuit.
Weather I get pc board etched (1sttimer) it would be helpful to have a second and third opnion if the copper traces are right as per schematic etc.
The 555/4017 are configured as a count to N and halt. The 555 output is enabled/disabled using the 2n3904 (Q1)
The uln2804 is a darlington array, allows interfacing to higher voltages (outside world, 12v dc)
The outputs of the 4017 are ORed using diodes D1-D4 which control the output of the 4030 exclusive OR gate
The output of the 4030 turns on or off the 2n3906 transistor which enables the relays RLY2 & RLY 3. If a yellow light is on then the Q2 transistor is on thus allowing a single red light if “driver” pushes the release button ( N O monetary pushbuttons connected to J-3.
Relays rly2 & 3 are configured to allow ONLY one red light, A first and only “ situation.
Relays rly 1 & 4 control the 24v dc solenoids and activate rly 2 & 3 if a red light is supposed to come on.
J2-pcb is connected to the solenoids thus isolating the 24v dc from any ground connections from the solenoids etc. No chance of ground loops etc. feeding back into 12v dc circuitry.
Had that happen ??
I tried using a mosfet as well as a triac (have lots of leftover from xmas computer display) couldn’t get either to work??
The relays were easier etc.
In spare time I kinda learned this pcb123 program. Pretty easy once you get the hang of it.
Decided to just f4 fun design a pc board for start tree
The proto-type is a real wiring mess. Cut wires trying different things, several unused transistors etc.
A real chance of a wire coming loose and disabling the circuit.
Weather I get pc board etched (1sttimer) it would be helpful to have a second and third opnion if the copper traces are right as per schematic etc.
