Looking for a 'tripwire' flashlight

[turbodog]

I need a light for the following problem. Will likely have to build something... but you never know.

Have a tornado shelter. Recently needed to get into it in the middle of the night in a big hurry. Did not have time to grab a light.

When got IN the shelter, needed a light immediately in order to close & lock the door. Depending on who may be in there (ie, not myself) they will not know where a light stashed in there is, how to turn it on, etc. Will quite likely not have time to find/figure this stuff out either.

I want to put a light in there with a string across the doorway. When you want through, the light comes on as you pull/run into/trip across/etc the string. It would be hooked to a switch that turns on and stays on.

Could NOT find anything like this using google.

If I have to I would build using a 4d battery box, emitter, heatsink, spring loaded microswitch with a paperclip holding it closed, and string tied to paperclip.

 

[LedTed]

One way to go would be to make your own with an ATTiny85 and a PIR sensor.

Simpler and easily set up with a tripwire would be a close pin deadman's switch. Though I don't recommend the string as it is a trip hazard.

 

[ZMZ67]

Have you considered a motion sensor light? I have used a Dorcy motion sensor night light with auto off in the kitchen for years with lithium AAs. It sees nightly operation and I only change the batteries maybe 3 or 4 times in a year.For a limited use space the batteries would last all year.

The model I use isn't on Dorcy's site anymore but they have some newer models. You may be able to find another brand besides Dorcy that is better quality although the Dorcy motion lights have worked fine for me. If nothing else it could be an interim light until you find or make something better.

 

[archimedes]

Do you intend for it to be "portable" ?

The reason I ask, is that this thread might otherwise be more usefully addressed in the Fixed Lighting forum.

 

[bigburly912]

I'd definitely go with a motion sensor light and maybe some tap lights down the entrance or in easy to find areas

 

[turbodog]

Given that the room is solid steel, there's enough vibration (for true motion sensing) and heat (for IR motion) that it would likely get tripped all the time. The string would just pull a small pin/wire/paperclip out and allow the switch to trigger.

 

[turbodog]

I'd definitely go with a motion sensor light and maybe some tap lights down the entrance or in easy to find areas

Not that big. Was retrofit into existing space. Is in corner of garage.

 

[turbodog]

Also, my main reason for not wanting motion sensing is that I don't have to wonder if it's triggering randomly and will be dead when it's needed. We don't go into the shelter very often... found some bottled water in there that was WAY past its prime. I am ok with a yearly battery replacement (due to the heat), but that's about it.

 

[turbodog]

Do you intend for it to be "portable" ?

The reason I ask, is that this thread might otherwise be more usefully addressed in the Fixed Lighting forum.

Probably not.

If you want to move thread that's cool. This was sort of a weird idea...

 

[archimedes]

Ok, moved to Fixed Lighting for you.

Might get more specific advice here, on what you are really wanting, instead of some kind of makeshift suggestions using kite string, duct tape, paper clips, and tape switches (lol)

 

[idleprocess]

I'd think that a battery box type arrangement with a standard on/off toggle switch and the tripwire removing an insulator from one of the battery contacts would be the way to go.

 

[archimedes]

There are "emergency lights" (luminaires) which automatically light when power is interrupted.

These might be able to be set up to function in the manner you seek ?

 

[turbodog]

There are "emergency lights" (luminaires) which automatically light when power is interrupted.

These might be able to be set up to function in the manner you seek ?

No power in the bunker due to it being all steel (conductive).

 

[turbodog]

I'd think that a battery box type arrangement with a standard on/off toggle switch and the tripwire removing an insulator from one of the battery contacts would be the way to go.

Had thought about the same idea.

 

[LRJ88]

Why not get a flashlight with a tail forward clicky, some PVC pipe, and then have the tripwire release a weight that activates the switch and lights up the tube?

https://imgur.com/a/7Q3j3oj

Something along these lines, the moment the pin is pulled the weight activates the flashlight, depending on if you just use a smooth pin for the trigger or something with a bit of a detent to make sure it doesn't get pulled on accident. It'd cost a grand total of some pocket change and can be directly mounted on a wall, board, anything where you can screw, glue, nail, staple, even velcro it onto. You can use any type of flashlight that has a forward tail clicky, throw in some lithium primaries and it's good for 10+ years.

 

[broadgage]

A simple and very reliable solution would be a light that is lit continually, this is now achievable with disposable batteries.
4 alkaline D cells and the brightest LED you can get.
Select the series dropper resistance to give a current of 2ma. That will give a run time of a year.
Leave a couple of flashlights with AA lithium cells where they are lit by this continually burning light and thus instantly located.

 

[lightfooted]

Given that the room is solid steel, there's enough vibration (for true motion sensing) and heat (for IR motion) that it would likely get tripped all the time. The string would just pull a small pin/wire/paperclip out and allow the switch to trigger.

Have you actually tried a motion sensor light in there to see how it would work? There are plenty of inexpensive ones that you could experiment with. They don't actually trip with just a certain level of heat you know...they use the Doppler effect to trigger. Even the cheap ones.

Although some really cheap devices that claim to "detect motion" are only using a light sensor and detecting a change in the level of ambient light...again you could experiment and discover what works.

Personally I think you're over-complicating it by trying to use a trigger that isn't really designed for that purpose. Especially when there are so many things already purposefully designed to do just what you want.

It also seems as though you should probably set up a schedule on which to check all of the supplies in the shelter. Checking the condition and functionality of the motion sensor light would naturally be a part of that so you could determine if it needs new batteries. Or that it in fact works at all.

Also consider the mechanics of the trip-wire, and how maybe over time something may cause it to jam just when you need it most (Murphy's Law) and even if you did decide to make it anyway...back it up with a motion sensor light.

There are also little battery operated lights with switches that resemble the common household style toggle style and have the LEDs in the faceplate. I found some at my local Parkrose Hardware. They can be stuck on the wall with double-sided tape or screwed into place. They are also inexpensive...less than $5 when I bought mine a year ago.

 

[turbodog]

Will see what I can come up with. The shelter being a large steel box, tends to resonate with vehicle noise when we are in the garage from engine noise, doors opening/closing, and so on. Given the high ambient temp, from living in the south, and from vehicle heat, batteries there don't last their rated life. On one hand it seems simple but there are complicating issues.

 

[datiLED]

I'd think that a battery box type arrangement with a standard on/off toggle switch and the tripwire removing an insulator from one of the battery contacts would be the way to go.

^^^Exactly. This would be the least complicated solution.

Use a switched 2D battery box with a cover and a heatsink with a reasonably large surface area. Add a NexGen converter board set to 250 - 333mA with a decent LED and you would be set. An extra set of batteries would give you days of runtime. *Remember to leave the switch in the on position.*

Cut a slit in the battery box cover (or back, depending on construction) above the contact and add an insulator between the battery and contact as idleprocess mentioned above. I would recommend using a pull chain or weighted string rather than a trip wire. Simply grab, pull and activate the light.

Glue several neodymium magnets to the box and mount it to the ceiling. (You mentioned the room was steel.). The box could be positioned as needed and moved once inside. Simple, inexpensive and effective.

 

[turbodog]

Tripwire (string) goes across doorway so you can't get inside without turning the light on. The other night... we needed to get inside extremely quickly. Should have been in there ahead of time.

To keep from reinventing the wheel I will find an existing magnetic light and retrofit a switch that I am looking for.