Are any exposure timers mechanical?

skinnedknuckles · Aug 7, 2023

I need a timer that will count down from the time I set it to.
I will not use it for darkroom enlarging but for boating navigation.
It must be mechanical (driven by spring and gears, not electric, not electronic).
It must have an analog pointer indicating the seconds to count down from.
It need not count down from more than 60 seconds.
It can have an electric switch for an enlarger but the timer must count down without it being plugged in.
I though maybe some really old timers might work this way.
For reference, I need a device exactly like the one shown in this video (but I will do without the bell if I have to).

Any ideas?

BrianShaw · Aug 7, 2023

Why not a count-up, like with an old-fashioned mechanical stopwatch?

skinnedknuckles · Aug 7, 2023

I need to make a turn to a new heading a specific number of seconds beyond a given landmark. I need a countdown timer because I can't be repeatedly looking down to check the timer while I'm driving the boat. With a countdown timer, I can set it easily enough and then start it (without looking down) when I pass the landmark and then make my turn when I hear the bell (without looking down).

BrianShaw · Aug 7, 2023

Check eBay (or other sources) for a Polaroid film timer. 120 seconds and below. Meets all of your other requirements, I think. There may even be a new version made (Impossible Project?) but I didn’t search for it as I’m sure that you can do that yourself.

What kind of boat are you piloting that turns every 60 seconds or less? Is a crew mate for calling timing out of the question?

skinnedknuckles · Aug 7, 2023

I don't need to turn every 60 seconds. Rainy lake in northern Minnesota and Ontario is a very dangerous lake to boat on because the bottom is all rock rather than sand. Many rocks are just a few feet below the surface so you have a good chance of ruining your prop/lower unit if you don't know exactly where you are. I once asked a speed boat prop repair shop in the Twin Cities where most of the props they fix come from and they immediately replied, "Rainy Lake" which is surprising since there are probably 5000 lakes between the twin cities and Rainy Lake.

Fortunately most turns can be associated with one of the many islands or visible rocks scattered across the lake. But on a few occasions, there is no landmark where a turn must be made so we maintain our heading past an existing landmark for a given amount of time and then make our turn. A 60 second timer allows us to identify a turning point as much as 3/4 of a mile beyond any existing landmark.

BrianShaw · Aug 7, 2023

Very interesting. Thanks for the detailed explanation. Best of luck in finding the right timer for your needs!

Sirius Glass · Aug 7, 2023

Welcome to ~~APUG~~ Photrio!!

STR1015 · Aug 19, 2023

Try searching on eBay for M.H. Rhodes Mark Timer. It looks like it's fully mechanical but I've never used one so don't take my word for it.

awty · Aug 19, 2023

All these 3 enlarger timers require power, will count down in seconds, but need power to operate, don't know if you could get them to work without.
The Mechanical darkroom timer only does minutes.

I just use my phone app to count down.
But then I would use my maritime GPS to navigate, it is the 21st century. I remember navigating at night without one...that is scary.
Must be smugglers.

Philippe-Georges · Aug 20, 2023

Can't you use a smart phone? These have good and trustworthy timers with sound signals (ringtones), it's electronic allright, but it can work independently for days if the battery is in good shape.
And to be sure you can always connect to a portable power bank or a solar cell.

There are waterproof covers, screen sensible, to protect them while surfing or swimming, which can be used on a boat too.

Sometimes I use mine in the dark room for timing the processing.

Bill Burk · Aug 20, 2023

GE Interval Timer is great if you can work with roughly 15 second time marks.

It’s great for outdoor uses, set the time, lower the arm (which charges the bell). When the minute hand hits the top the bell rings and the arm lifts. You can tie the arm to a flag or maybe a switch.

These are cheap and plentiful.

Bill Burk · Aug 20, 2023

This plastic variant is mechanically the same.

The bell is loud and a flag would be just what you want…

I think you would want either this or the black metal one like mine.

Set the dial at 1… when you see the landmark yank the flag… when the bell rings and the flag goes up you know it’s safe to turn.

Molli · Aug 20, 2023

Searching for a mechanical kitchen timer seems like your best bet, although possibly the durations are too coarse for your requirements. There are, of course, battery run LCD digital ones and an egg timer of that variety might suit.

Failing that, you need yourself a Sam Vines, but he's only available on the Discworld unfortunately.

MattKing · Aug 20, 2023

This makes me think of the Kodak timers, but I don't recall if they count down:

Bill Burk · Aug 20, 2023

Kodak timers count forward. They tick in quarter seconds so you can use them a bit like a metronome.

But they just tick how much time has gone by since you flicked the lever.

Two knobs on the back let you spin the minute and second hands independently.

A little on the finicky side. Mine needs a cleaning.

I hear Mobil 1 series synthetic oil is good for clocks so I got this…

awty · Aug 20, 2023

Philippe-Georges said:
Can't you use a smart phone?

Smugglers can't use smart phones, haven't you seen the movies. You have to be very sneaky or the customs officers will spot them. No lights or traceable devices. Hard to find the secret cave at night. Needs a rope with a lead sinker and knots in fathom intervals.....6 fathoms and all's well.

Are any exposure timers mechanical?

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