Flashing tank light

[burna]

Crappy weather has lead me to small project I've been meaning to do for ages. Build my own flashing tank light to replace those cylume sticks.

The pictures are pretty self explanatory, and, as you may also notice, I didn't spend much time making it look pretty.

Parts list.

AAA battery x 2.
Flashing LED about $1.00
Reed switch $1.50
Housing is an old toothbrush container used for travelling.

I wanted a normally closed reed switch, but they must have given me the wrong one so I need to come up with a way of holding the magnet in place. I am also yet to seal up the end, just plan on filling the end with silicone.

I have a MkII in mind where I have an old rear bike light that has a module incorporating a couple of flashing modes. Instead of using the button to switch through the modes I think I could use the reed switch and then would only need the magnet to turn it on a off so could leave the magnet in my car.

 

[MrSpock]

Great idea! How did you waterproof the toothbrush container?

 

[burna]

You mean seal the end? I thought I might just fill up the end with silicone sealant.

 

[MrSpock]

Hmm... Not being skeptical, but... would the water pressure break the container?

 

[burna]

I think it will be strong enough, it seems quite strong and has no flex when I push on it. I was going to put it inside some clear plastic tubing but wanted something frosted (don't know the proper term) to diffuse the light a bit.

Do you have a suggestion for the container, I am very much open to other ideas.

Thanks for your feedback.

 

[MrSpock]

I think it's a brilliant idea! It's true penny-tech engineering! Blinking LED cost next to nothing. So do batteries. DIY application is pretty safe. And it's not a life-critical piece of equippment.

We'll see after your first dive if it leaks. Another issue is if you seal the end with silicone you'll need to reseal it every time you change the batteries.

Idea: If you could find an old electric rechargable toothbrush you could use the batteries and charger from it. The one which charges without any metal contacts. Then you can seal the container completely.

Good luck and please keep us posted!

 

[promocop]

FYI you can buy this set up for $5.95 from scuba toys and it wont blow up under pressure,

 

[burna]

FYI you can buy this set up for $5.95 from scuba toys and it wont blow up under pressure,

Yep, and for another $35 postage I can get it sent to me.

Thanks for the tip.

 

[Damselfish]

Maybe consider making a non-flashing one? A flashing light won't bother you because it's behind you, but it's really annoying for other people to have to see the whole dive.

 

[antero]

Baby soda bottle (PET test tube used to blow coca bottles) makes non-destructible and water tight container for your blinkers or laser pointers. And it cost a dollar in a hobby shop. But why do we need it underwater? To establish a reliable visual reference for marking an exit line or something like that tiny blinker is not powerful enough - we need a strobe...