I have designed a circuit and it is working. However, I think it is too complicated and can be changed or simplified. I might be missing something. I am finding hard to create a 1 second delay.
A locomotive has to run, without attention, backwards and forwards along a length of track. At each end it is to stop for about a second before starting in the reverse direction. light dependent resistors (LDR) are used as sensors and they are under the track. The H-bridge has two logic inputs, X and Y, to control the polarity of the track; X high Y low makes the engine move in one direction, X low Y high makes it move the other way. X and Y in the same state disconnect the supply from the track and stops the engine.
I have access to:
- 4016 quad bilateral switch
- 4027 dual J-K master/slave flip-flop
- 4093 quad 2-input Schmitt NAND
- 4520 dual 4-bit up counter
- 4538 dual re-triggable monostable
- DG211 and DG212 quad analogue switch
- 555 timer