the circuit
This is the circuit for the parallel 8-bit interface:
10 11 12 13 15 23-24-25 2 3 4 5 6 7 8 9
| | | | | ____| | | | | | | | |
|D1 |D2 |D3 |D4 |D5 | | | | | | | | | |
--- --- --- --- --- | -+--+--+--+--+--+--+--+--+-
\|/ \|/ \|/ \|/ \|/ | | ULN 2803 /|
--- --- --- --- --- | | \|
| | | | | | -+--+--+--+--+--+--+--+--+-
| | | | | | | | | | | | | | |
-R1 -R2 -R3 -R4 -R5 | | | | | | | | |
| | | | | | | | | | | O1 O2 O3 O4 O5 O6 O7 O8
| | | | | | | | | | | | | | | | | | |_________________
- - - - - | | | | | | | |______________ |
| | | | | | | | | | | |___________ | |
I1 I2 I3 I4 I5 I0 | | | | |________ | | |
| | | | |_____ | | | |
| __| | |__ | | | | |
| | | | | | | | |
| -R6 -R7 -R8 -R9 -R10 -R11 -R12 -R13
| | | | | | | | | | | | | | | | |
| | | | | | | | | | | | | | | | |
| - - - - - - - -
| | | | | | | | |
| ---L1 ---L2 ---L3 ---L4 ---L5 ---L6 ---L7 ---L8
| \|/ \|/ \|/ \|/ \|/ \|/ \|/ \|/
| --- --- --- --- --- --- --- ---
| | | | | | | | |
| +-----+-----+-----+-----+-----+-----+-----+-----> +9..12V
0V_|_
2..25: parallel port
D1..D5: 1N4148
R1..R5: 1K
R6..R13: 33K
L1..L8: LEDs
I0: input ground
I1..I5: inputs
O1..O8: outputs
I recommend to use relais and an extra power source for electric motors.
24.10.99 - (C) Ben Fuhrmannek <ben@fuhrmannek.de>