I have a old engine with a pionts system.
I want to count the pules and convert to a rpm count.
When i tried this I thought to connection the board (input1) to the - side of the coil which turns on and off as the engine revs.
Is this right? Or will the Voltage be too high? Where should i connect it and how?
Thanks ROb 
How high it the voltage from the coil?
Since the absolute maximum input voltage to the ULN2803 is 30V.
You may use the internal pulse counter of the K8055 to count the pulses and calculate the RPM.
Well i think i blew the board. Certain inputs now read always on…
Can i replace the ULN280? Where can i get it?
is this suitable?
cgi.ebay.co.uk/ws/eBayISAPI.dll? … K:MEWAX:IT
Yes, this ULN2803 is suitable.
Just plug it in and itll work again?
If i switch the 2 chips around i get all my outputs working but input 1 dosent register.
Advice?
thanks Rob
If you have a multimeter you may check if there is any voltage swing on the input pin 1 and on the output pin 18 of IC2.
Pressing button SW1 should cause about 5V swing on these pins.
Disconnect all external circuit from the digital input of the card.