Monostable timer > LCD counter

I have a LCD counter module which notches up 1 digit each time +1.5V is applied to the input (for a minimum of 100 microseconds), and want to use it to display the accumulated time that some equipment is being operated.
My thoughts are along the lines of building some kind of monostable circuit with one input and one output, the input being either 0v or 9v (9v signifying that the equipment is being operated). This input would start the monostable which would provide a series of pulses at the output 1 minute apart, which could be counted by the LCD counter.

Does this sound feasible, or is there a better way to achieve this (using the LCD module which I have already bought!)

For a minute period, an analog astable circuit would not be very practical so some form of counter circuit is more appropriate. For best accuracy you would want a crystal oscillator driving a digital counter/divider circuit. For example the 4060 CMOS 14-stage counter will give you two pulses per second output with a 32,768kHz clock crystal. You can then use another counter to divide that by 120 to give a once per minute pulse.

If you don't need high accuracy then you could use an RC oscillator (such as a 555 connected in an astable configuration) instead of the crystal. You could set it's frequency to 1Hz and then just divide that by 60 with a counter/divider to get the once per minute pulse.

Thanks Carl, I'll go with option 2, as accuracy is not essential.
What would you recommend I use as a counter/divider?

Rosso said:

Thanks Carl, I'll go with option 2, as accuracy is not essential.
What would you recommend I use as a counter/divider?

Click to expand...

hi,
As you are going with Carl's opt2, look at the HEF4521 IC, it can be configured to give 1min pulses using R/C timing.