Hi everyone,
I'm new here, I came specifically looking for help with a timer I need to make. It's been about 20 years since I did any real electronics, and even then I could construct circuits and PCB's but was never any good at designing them- so any help would be gratefully appreciated!
What I want to make is the following:
A timer with LCD display that will measure to at least two if not three decimal places of a second. It doesn't really need to measure in minutes, and definitely not hours.
I want to have count-up and count-down functions. When in count-down mode, I need to be able to set the starting time, obviously (say, 5 seconds, 10 seconds, etc), and also have an audible alarm/buzzer when the time reaches zero.
It would be nice on the count-up function to have a delayed start, with a buzzer sounding at the actual start point (i.e, press start, have a few seconds delay, then an alarm sound, then the actual timing process starts).
The above two features could be rolled into one with a count-down timer that allowed an over-run, and sounded an alarm at zero. That way, the delayed start could be set by the count-down with the over-run value actually being the count-up time- if that makes sense?
I also need to start and stop the timer with a foot switch, but I guess that is by-the-by. It would be better if this was optional, so the timer also had it's own start/stop switch, with the option to switch externally as and when required.
Could anyone point me in the right direction of a circuit that would do this? I already have a bench timer that supposedly does most of this, but it only measures to whole seconds, and when an external start/stop switch is connected, ALL of the devices buttons are disabled, so you have to disconnect the switch if you want to change the count-down time or even reset it. Stupid really. If I could somehow modify that timer to display in fractions of seconds, I'm sure I could re-wire the external switch connections to run off the device buttons, thereby bypassing the lock-out of all the other buttons- this would probably be the easiest option, rather than starting from scratch, but again I have no idea how I would go about altering the timer resolution.
Many thanks in advance everyone.
I'm new here, I came specifically looking for help with a timer I need to make. It's been about 20 years since I did any real electronics, and even then I could construct circuits and PCB's but was never any good at designing them- so any help would be gratefully appreciated!
What I want to make is the following:
A timer with LCD display that will measure to at least two if not three decimal places of a second. It doesn't really need to measure in minutes, and definitely not hours.
I want to have count-up and count-down functions. When in count-down mode, I need to be able to set the starting time, obviously (say, 5 seconds, 10 seconds, etc), and also have an audible alarm/buzzer when the time reaches zero.
It would be nice on the count-up function to have a delayed start, with a buzzer sounding at the actual start point (i.e, press start, have a few seconds delay, then an alarm sound, then the actual timing process starts).
The above two features could be rolled into one with a count-down timer that allowed an over-run, and sounded an alarm at zero. That way, the delayed start could be set by the count-down with the over-run value actually being the count-up time- if that makes sense?
I also need to start and stop the timer with a foot switch, but I guess that is by-the-by. It would be better if this was optional, so the timer also had it's own start/stop switch, with the option to switch externally as and when required.
Could anyone point me in the right direction of a circuit that would do this? I already have a bench timer that supposedly does most of this, but it only measures to whole seconds, and when an external start/stop switch is connected, ALL of the devices buttons are disabled, so you have to disconnect the switch if you want to change the count-down time or even reset it. Stupid really. If I could somehow modify that timer to display in fractions of seconds, I'm sure I could re-wire the external switch connections to run off the device buttons, thereby bypassing the lock-out of all the other buttons- this would probably be the easiest option, rather than starting from scratch, but again I have no idea how I would go about altering the timer resolution.
Many thanks in advance everyone.
