Hi - first post so be gentle !

I fire professional firework displays for a living , no - I dont want help building something to fire fireworks electronically - can already do that !

I have been searching all over the UK for an LED stopwatch -with displays like the old fashioned digital watches - red 7 segment things.

Many LCD ones out there - but they are of no use - I need something that is visible at night, they all have backlights - but they go out - and holding in the button does not work.

- I need something that will stay constantly visible with no input from me that will count up in seconds:minutes. and that I can attach to a clipboard or to my firing system or to my wrist or to my gas bottle if I am hand firing anything.

I have nearly no practical electronics experience - but can use a soldering iron !

I am not looking for anyone to design me a circuit or give me a parts list as such, but would love to know -

Would it be feasible to take an LCD stopwatch/timer, and replace the display with an LED type display ?

It would not need to go back into its original case - I would of course have to find some other enlosure for it.

Or is this idea a non starter ?

Failing this - are there any places out there where a complete novice can by a kit or something like this to build a simple count-up minute:second timer ?

Many Thanks

Gerry

__________________
'Put your trust in God my boys, and keep your powder dry' - Oliver Cromwell.

Jubilee Fireworks

 

Changing an LCD to an LED isn't easy. All the voltages, currents are different. You also have to work out what the multiplexing scheme is, and the physical connections may be very small and of a type that is difficult to get wires soldered on to.

I have three possible suggestions.

1) Open up a stopwatch and find the backlight. Wire that directly to the battery. Some will use an electroluminescent backlight which is fed by an inverter so it is the inverter that you need to wire to the battery.

2) Find a stopwatch (or something that has a stopwatch function) that can run from external / mains power. They are more likely to have a way of leaving the backlight on permanently. Something like this:- CAL CONTROLS | ETM1411-2307 | Timers & Counters | Industrial Controls & Automation | Farnell UK

3)Roll your own with LED displays and either several clock and driver ICs or a microcontroller. It's not a difficult project but if you need to learn about microcontrollers first that is quite a lot of effort.

 

Thanks Diver

I had a feeling things would not be that simple as swapping displays !

Would I be on the right lines in getting something like this ?

ON/OFF DIGITAL RED LED TIMER CLOCK TIME COUNTER METER - eBay (item 260300797653 end time Oct-20-08 03:44:24 PDT)

I cant figure out if it is a choice of seconds - minutes or hours, or if it will show mins and seconds which is all I need.

They sent me a basic diagram but it appears to be a very similar but not identical product . . .

Attached Files

365um5140tdCountdown.pdf (186.8 KB, 64 views)

__________________
'Put your trust in God my boys, and keep your powder dry' - Oliver Cromwell.

Jubilee Fireworks