Idea: Cache with 3-volt electricity

[+FolsomNatural]

There's an easy way to add electricity to a cache - -

to power an LED light for example, or a buzzer.

 

You tap into the Ni-Cad battery of a hand-crank emergency radio.

 

Some details at:

 

hand crank radio

[+FolsomNatural]

Photos for the above:

 

Assembly

 

 

Tapping into the battery

 

Schematic

[+eusty]

It's a good idea for lower voltages, but not much good for powering a solenoid Unless you can get 3v solenoids.....(I'm off searching now!)

[+DonB]

Just make your own power supply. You can buy Ni-MH AA batteries with solder tabs and series/parallel them for more capacity or just series them to come up with any voltage you need by adding more batteries.

Edited June 18, 2012 by DonB

[+ras_oscar]

Or you can adjust the circuity to run off 2 AA batteries, that are sitting in many people's GPS already.

[+FolsomNatural]

The real trick is getting the hand-crank generator.

 

That comes built in on the emergency devices.

Even a charged Ni-Cad battery is not going to last very long.

 

Yeah, I've seen the caches where you have to take the batteries out of your GPS and insert them

in the cache to make something move.

Clever, but I consider it "cheating" a little bit anyway.

[+fuzziebear3]

Most folks carry extra batteries with them anyway, don't they?

 

Plus, if you include on the cache page to bring your own batteries, then they will know to be prepared

[7rxc]

Interesting how all the text says NiCad and the photos all show NiMh batteries. Perhaps it's like wanting a Tylenol and asking for an Aspirin? Funny how language is like that.

 

As for 3 volt solenoids, they should be possible and available. We used to make decent electromagnets out of nails, wire and a 2 volt carbon cell. That was when I was a kid way back. Since the advent of modern electronics I don't think there is a problem. Or you might have to use a small relay to engage a bigger battery inside (solar charged?). I got the impression that the idea was for a display of information, not a locking system originally, but it's a fair question to ask about solenoids.

 

Doug 7rxc

[+eusty]

As for 3 volt solenoids, they should be possible and available. We used to make decent electromagnets out of nails, wire and a 2 volt carbon cell. That was when I was a kid way back. Since the advent of modern electronics I don't think there is a problem. Or you might have to use a small relay to engage a bigger battery inside (solar charged?). I got the impression that the idea was for a display of information, not a locking system originally, but it's a fair question to ask about solenoids.

Actually 3v solenoids are not that easy to find...had a quick look on ebay.

[+kunarion]

There's an easy way to add electricity to a cache - -

to power an LED light for example, or a buzzer.

 

You tap into the Ni-Cad battery of a hand-crank emergency radio.

I recently went to a "dollar store" and found a pile of "emergency LED flashlights", keychain sized. They have a squeeze-style crank to power the light, they didn't seem to "charge" a battery. Most didn't work, but you could find a few that do.

 

If you could put one in a watertight box somehow, replace the entire "emergency light" when it goes bad. You can find battery-powered LED penlights on ebay in bulk for less than a dollar, even UV lights.

 

That same store had "solar hula dancers" -- a solar cell runs a tiny motor, only while illuminated. There are probably some creative uses for that circuitry, and you don't break the bank. I haven't opened one of those things, but maybe there's a tiny, weak solenoid in there.

Edited June 18, 2012 by kunarion

[knowschad]

Interesting how all the text says NiCad and the photos all show NiMh batteries. Perhaps it's like wanting a Tylenol and asking for an Aspirin? Funny how language is like that.

 

As for 3 volt solenoids, they should be possible and available. We used to make decent electromagnets out of nails, wire and a 2 volt carbon cell. That was when I was a kid way back. Since the advent of modern electronics I don't think there is a problem. Or you might have to use a small relay to engage a bigger battery inside (solar charged?). I got the impression that the idea was for a display of information, not a locking system originally, but it's a fair question to ask about solenoids.

 

Doug 7rxc

 

Very good point! I used to do the same thing. No reason it couldn't be handmade today! It wouldn't have much strength, and you'd need to avoid friction as much as possible, but teflon tape should help with the latter, at least.

 

Edit to my comment about strength!

 

Where a choice is available it should be remembered that a low voltage coil tends to givemore power than one for high voltage, and is more robust as it uses heavier wire.

source Edited June 18, 2012 by knowschad

[+ras_oscar]

Most folks carry extra batteries with them anyway, don't they?

 

Plus, if you include on the cache page to bring your own batteries, then they will know to be prepared

 

"zactly what I was thinkin. ( of course I never read the cache page befor I go out huntin')

[7rxc]

As for 3 volt solenoids, they should be possible and available. We used to make decent electromagnets out of nails, wire and a 2 volt carbon cell. That was when I was a kid way back. Since the advent of modern electronics I don't think there is a problem. Or you might have to use a small relay to engage a bigger battery inside (solar charged?). I got the impression that the idea was for a display of information, not a locking system originally, but it's a fair question to ask about solenoids.

Actually 3v solenoids are not that easy to find...had a quick look on ebay.

Ebay? I searched for 'solenoids' and found lots of manufacturers listings, and all of them had ones that operate 3 to 9 volts.

 

I haven't even started looking at 'robotics suppliers'. I can see several uses for such things... granted 5 volts would be a better source. However, I don't intend to keep looking much. I did try a nail magnet on two volts and it has fair pull still. So I'm sure it could be done economically if needed.

 

Doug 7rxc

[+eusty]

Ebay? I searched for 'solenoids' and found lots of manufacturers listings, and all of them had ones that operate 3 to 9 volts.

 

I haven't even started looking at 'robotics suppliers'. I can see several uses for such things... granted 5 volts would be a better source. However, I don't intend to keep looking much. I did try a nail magnet on two volts and it has fair pull still. So I'm sure it could be done economically if needed.

There are plenty of pneumatic solenoid valves which operate on 3v, but nothing which would work a catch, apart from maybe a gas solenoid ...that's on the UK version of ebay