Looking for a 'tripwire' flashlight

Dave_H

Enlightened
Joined
Nov 3, 2009
Messages
796
Location
Ottawa Ont. Canada
You may have seen these cheap LED cabinet lights which come on when a door is opened, after a small magnet
normally close to the unit is pulled away. They use internal reed switch or Hall-effect sensor. I have a few and
they are not very bright, use button cells. Something brighter no doubt exists, or principal could be applied to
custom but not very complex interface. Just connect trip wire to a suitable magnet and position it close to light.

Dave
 

Ken_McE

Flashlight Enthusiast
Joined
Jun 16, 2003
Messages
1,686
For your consideration:

Buy a household wall switch, the kind that is mounted just inside the door and flips up and down. Buy a box to mount it in. Drill a small hole through the end of the switch and thread through a small split key ring. The ring is there to make it easy to tie a thread to it. Mount it by the door, but mounted sideways, not up and down.

Run a thread from the latch side of the door to the switch - the ring makes it easy to fasten a thread securely. If the door is steel, a magnetic hook stuck on the inside would be easily adjustable and so perfect for the door side.

When the door is opened it pulls the thread, the thread first flips the switch and then breaks. Leave enough slack in the setup that you can reach around an almost closed door and rig a new string on your way out. Now you have a tripwire, but it uses the door instead of your face to activate.

The direction you mount the switch in is whatever matches up the "ON" position to the swing direction of the door. You will need to experiment to get the right thread. You want it to reliably flip the switch but not tear it off the wall. The switch of course controls a light setup that is mounted in the shelter. How plain or fancy is your call.
 
Last edited:

turbodog

Flashlight Enthusiast
Joined
Jun 23, 2003
Messages
5,964
Location
Southern USA
For your consideration:

Buy a household wall switch, the kind that is mounted just inside the door and flips up and down. Buy a box to mount it in. Drill a small hole through the end of the switch and thread through a small split key ring. The ring is there to make it easy to tie a thread to it. Mount it by the door, but mounted sideways, not up and down.

Run a thread from the latch side of the door to the switch - the ring makes it easy to fasten a thread securely. If the door is steel, a magnetic hook stuck on the inside would be easily adjustable and so perfect for the door side.

When the door is opened it pulls the thread, the thread first flips the switch and then breaks. Leave enough slack in the setup that you can reach around an almost closed door and rig a new string on your way out. Now you have a tripwire, but it uses the door instead of your face to activate.

The direction you mount the switch in is whatever matches up the "ON" position to the swing direction of the door. You will need to experiment to get the right thread. You want it to reliably flip the switch but not tear it off the wall. The switch of course controls a light setup that is mounted in the shelter. How plain or fancy is your call.

Could be ok. I have to deal with the door opening different amounts. Could be halfway, could be wide open if the wind hits it.

I've got some magnetic mount lights on order. Will see what I can do. Pics will follow eventually.
 

TechGuru

Newly Enlightened
Joined
Sep 24, 2017
Messages
133
Location
TEXAS
Whatever you go with I'd recommend (Energizer) Lithium batteries instead of alkaline.
 

turbodog

Flashlight Enthusiast
Joined
Jun 23, 2003
Messages
5,964
Location
Southern USA

turbodog

Flashlight Enthusiast
Joined
Jun 23, 2003
Messages
5,964
Location
Southern USA
Think I may take the housing that does NOT work and rewire it with a manual switch for the string.
 

Dave_H

Enlightened
Joined
Nov 3, 2009
Messages
796
Location
Ottawa Ont. Canada
PIR sensors - which those appear to use - consume power, thus I'd expect to be swapping cells on a schedule.

I have used a number of LED battery-powered PIR motion sensing lights; there are good ones and less good ones.

Many run on 3xAAA, better ones take 3xAA or 4xAA. I've measured standby current which can slowly run
the batteries down even with lights off. For good design its is 100uA or less (or maybe a bit higher). One case
was >1mA, which for a set of AAA alkalines will last mere weeks. This spec (standby current drain) is never
listed for the product.

Other type of lights like this are ones with IR remote control. The IR receiver has to be on all the time. Same
considerations apply.

I use a 4xAA PIR light in back shed and it normally holds up for several months including some on-time,
even in winter. Similar for a 3xAA light in the basement.

Dave
 

idleprocess

Flashaholic
Joined
Feb 29, 2004
Messages
6,504
Location
dfw.tx.us
I have used a number of LED battery-powered PIR motion sensing lights; there are good ones and less good ones.

Many run on 3xAAA, better ones take 3xAA or 4xAA. I've measured standby current which can slowly run
the batteries down even with lights off. For good design its is 100uA or less (or maybe a bit higher). One case
was >1mA, which for a set of AAA alkalines will last mere weeks. This spec (standby current drain) is never
listed for the product.

I have a generic 3xAA model that I got off of a surplus site years ago that I have used in the guest bathroom (infrequently used). If positioned so as to minimize nuisance trips it lasted 3-6 months on a set of LSD 2Ah NiMH cells.

Mr Beams is a brand that's had some staying power on the likes of the 'Zon.
 

turbodog

Flashlight Enthusiast
Joined
Jun 23, 2003
Messages
5,964
Location
Southern USA
Have tried 2 ready-made lights.

https://www.amazon.com/gp/product/B00H7OODQO/ref=ppx_yo_dt_b_asin_title_o01_s03?ie=UTF8&psc=1

https://www.amazon.com/gp/product/B00H7OODNM/ref=ppx_yo_dt_b_asin_title_o01_s01?ie=UTF8&psc=1

#1/Square one is terrible. Turns on, stays on, Won't turn on. Etc.

#2/round one is ok. Will mount it.

Have no way of knowing if they false positive and run batteries down.

The #2/round one is decent. Turns on like it should. No word on battery life. Magnets are pretty weak. Slides down a steel plate wall.


I took #1 and salvaged the small leds from it. Soldered 4 of them in parallel. Wired a microswitch into place. Fed it all with a standard 123 lithium cell (can withstand the heat/cold) in a spring loaded cell holder. Mounted all this to a 2x4 board about 1 foot long.

Stuck the board to the wall of the shelter using some magnets from amazon. Put another magnet on opposing wall. Pulled string between magnet and metal 'pin' that holds microswitch down.

When you walk through the door, the string pulls the pin out, microswitch contacts close, and leds come on.
 

Lynx_Arc

Flashaholic
Joined
Oct 1, 2004
Messages
11,212
Location
Tulsa,OK
I would just go with a mechanical switch that is very close to the door that you can turn on/off when you enter/exit. I've been in basements and closets all my life that you open the door and turn on the light and turn off the light and close the door. Just make sure when you turn the light on/off you can see it on regardless of the time of day/night so you can make sure and turn it off. One other thing if your shelter is large you can put in a a pair of 3 way switches one on the inside and one on the outside and install indicator lights on them to show power on/off. This way you can turn the light on before you enter and if you forget you can turn it on while inside and off also when you want to sleep inside.
 

adnj

Enlightened
Joined
Aug 13, 2006
Messages
699
I only skimmed the thread...

If the structure is steel, run 12 volt into it from an outside 120/12V transformer or solar panel to keep a small gel battery charged.

Use a burglar alarm microswitch to sense the door open/close and a wall switch for override while inside.

Illuminate with whatever you want. Install a 12V cigar lighter socket for accessories, phone charger, etc.



Sent from my LG-V520 using Tapatalk
 
Last edited:

turbodog

Flashlight Enthusiast
Joined
Jun 23, 2003
Messages
5,964
Location
Southern USA
I only skimmed the thread...

If the structure is steel, run 12 volt into it from an outside 120/12V transformer or solar panel to keep a small gel battery charged.

Use a burglar alarm microswitch to sense the door open/close and a wall switch for override while inside.

Illuminate with whatever you want. Install a 12V cigar lighter socket for accessories, phone charger, etc.



Sent from my LG-V520 using Tapatalk

Yes, it's steel. I like the idea of a gel cell on charge. Might come back to that this fall/winter when things slow down some.

As an aside, I don't think people are really understanding the main problems I encountered:

1. need a light that turns on automatically... not all people know where a switch is, or have time (in a panic) to find it
2. main power could be out, so you could be entering in the dark
3. battery needs to stand up to heat/cold, shelter is in corner of garage
4. can't run a/c power due to steel structure and risk of electrocution if tree falls through roof/etc
5. very high risk of accidental turn on due to the entire structure vibrating/resonating from vehicle noises in garage

The other day (about 2-3 months ago now) we needed to be in the shelter. There was zero time to grab a light on the way out the door... and that's significant as they are stashed all over the house. Made me realize the need for an auto light.

It's not a huge shelter, but is rated by texas tech for f5 storms.
 

kingofwylietx

Enlightened
Joined
Feb 26, 2010
Messages
445
Location
DFW, TX
Just grab a few of those cheap plastic D-cell flashlights that are brightly colored. Throw them in there, anyone going inside will see them or feel them when feeling around.

Or, hang one on the outside of the shelter by a string that people can grab on the way inside.

I don’t imagine there will be any strangers going in there because a stranger will not know that you have a shelter. Whoever yells “run to the shelter” can also yell “and grab the flashlight off the handle on your way in”.
 
Last edited:

AstroTurf

Enlightened
CPF Supporter
Joined
Jan 21, 2020
Messages
823
Location
USA RVA
I have a zebralight headlight mounted to the strap on the back of a ballcap on my nightstand at night. It is always on the lowest lumen setting. Always setup in the same way/position every night. Quickly secured on my head, and a quick double click gives me all the light i need to relieve myself in the toilet. Disciplined repeatable actions are whats needed. IMHO.

Jim
 

turbodog

Flashlight Enthusiast
Joined
Jun 23, 2003
Messages
5,964
Location
Southern USA
Well running for your life with no notice removes time to grab things. It also injects adrenaline which decreases fine motor skills. Before the other night's storm I would agree with all these 'plans'. Afterwards... nope. Need something automatic.
 

Lynx_Arc

Flashaholic
Joined
Oct 1, 2004
Messages
11,212
Location
Tulsa,OK
A battery powered light with a switch on the outside and another on the inside so before you go in you turn the light on and a bug out bag inside of the room full of stuff including other lights and lanterns. Even in a hurry people can shut doors and turn lights on/off easily if the switches are placed correctly.
 

turbodog

Flashlight Enthusiast
Joined
Jun 23, 2003
Messages
5,964
Location
Southern USA
A battery powered light with a switch on the outside and another on the inside so before you go in you turn the light on and a bug out bag inside of the room full of stuff including other lights and lanterns. Even in a hurry people can shut doors and turn lights on/off easily if the switches are placed correctly.

That's great unless the A/C power is off.

I think we're gonna have to agree that we don't see eye to eye.

Thanks.
 

idleprocess

Flashaholic
Joined
Feb 29, 2004
Messages
6,504
Location
dfw.tx.us
That's great unless the A/C power is off.

I think we're gonna have to agree that we don't see eye to eye.

Thanks.

Everybody has a plan until they get punched in the mouth.

Every evening I have the often humbling experience of trying to manage the process of starting to walk the dogs. A series of things has to happen in about 30 seconds:
  1. Grab hat
  2. Grab crap sacks
  3. Collect the leashes that the mutts have been dragging behind them
  4. Retrieve keys from pocket
  5. Open the door without allowing cat to bamf through it
  6. Expel the dogs
  7. Close the door
  8. Lock the door
  9. Pocket keys
  10. Extract flashlight from pocket and light it
  11. Ensure the mutts aren't experimenting with perpetual motion

Steps 1 through 5 have to be completed before the senior mutt decides that he's transcended the requirement of urinating outside. Steps 5 through 7 must be performed as fast as possible. Step 8 & 9 are also ideally done as fast as possible so the dogs can perform a #1 on the lawn as opposed to the walkway; the dogs are typically exerting maximum tension on leashes at this point. Steps 9 through 11 are also ideally done as soon as possible since such antics will likely make them sick ... hours later when the causality is utterly lost on them.

While I can usually pull this rehearsed sequence of events off without a hitch, there are still errors several times a week. Usually these are recoverable. But sometimes exciting things happen such as the cat ninja'ing so as not to alert the dogs then bamf'ing out the door, dropping my keys at an inopportune time, forgetting the crap sacks, one of the mutts slipping a harness, a loose dog exciting the mutts, or locking the door / pocketing keys / fumbling for that flashlight as the dogs attempt to wrench my arm out of socket in their eagerness.

And all of the above is routine. I can't imagine being jarred into action from a deep sleep - fighting sleep disorientation - scrambling into a shelter for safety and expecting to have the presence of mind to locate and switch on a flashlight. As such I appreciate the simplicity of the tripwire, which buys some time to spool down a likely adrenaline rush without the added stress of fumbling around for something that's going to require fine motor skills to operate. Given the somewhat low likelihood of needing to make that mad dash to the shelter, practicing under realistic conditions isn't feasible and the tripwire solves the problem in an expedient fashion.
 

adnj

Enlightened
Joined
Aug 13, 2006
Messages
699
I have some property on an island that has a large house, a so-so public electrical supply, high risk of tropical storms, and an 8" concrete wall safe room.

Lights are automatic. There is a whole house LPG back-up generator, battery back-up for the safe room lighting, 4000 gallons of on-site potable water storage, 8 spare 18650 flashlights, battery backup for the entry gate and the garage door, handheld VHF 2-way radios, and 3 spare cell phones with chargers.

Everytime there is a storm or a power outage, something unexpected seems to happen. The best laid plans...

Sent from my LG-V520 using Tapatalk
 
Top