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Light Dimmer

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duda123

Member
Hey guys! This is my first post here and I already need some help!

Electronic is kind of a hobby for me, but I don't have much knowledge on it smirk

Here's what I need help with:

I'm trying to create a keychain that glows stronger while you're walking... but I'm only going to do that if the circuit it pretty simple (as I said before, I'm not an expertise in electronic circuits).

It should work like a light dimmer... if you stand still, it's going to slowly become less and less brighter until it turns off. If you start moving, it's going to slowly get brighter and brighter.

I guess I could use a mercury switch to check if the person is walking or not, but I've no idea on how am I going to do the circuit itself...

I hope you can help me!

Thanks,
Eduardo.
 

MikeMl

Well-Known Member
Most Helpful Member
Take apart a pedometer, and do some testing with the switch.
 

duda123

Member
Okk... but... assuming I have the pedometer switch, how can I make it control the LED as a light dimmer?
(as I said, I don't have much knowledge with electronics)

If it would make it easier, the circuit switch can be any kind of button, instead of a pedometer switch... I can modify the switch to a pedometer switch by myself :)

Cheers,
Eduardo.


Edit:
I found this circuit online:
https://www.redcircuits.com/Page9.htm
But I'm not sure if that can help me somehow!

Thanks!
 
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MikeMl

Well-Known Member
Most Helpful Member
Assuming you have a swing-weight switch like would be inside the pedometer, presumably either one of two things will happen: as you walk faster, either the duty-cycle (ratio of how long the switch contacts are closed vs. how long they are open) will increase, or the rate at which the contacts close-open will increase. You measure the duty-cycle and rates, come back, and we can do the rest.
 

HarveyH42

Banned
Maybe a little over simplified, but couldn't the switch be used to apply voltage to a capacitor, parallel to the light with each step? Probably take some experimenting to smooth it out, and figure out how big a capacitor to use, maybe a resistor to limit how fast it charges. But if each step could put a little more into the capacitor, than the bulb uses, it would slowly get brighter. When you stop, the capacitor would drain, bulb would fade out...
 

DerStrom8

Super Moderator
Another idea would be to use a magnet and a coil. You may have seen those flashlights that you shake, and the internal magnet induces a current in the coil, which is then stored in a capacitor. If you adapt this to work while you're walking, the magnet will move and the current in the coil will charge the capacitor, which would have the light attached. If you stop, current from the coil stops, the capacitor discharges, and the light goes out.
I realize that this is really rough, will take a while to adjust so that it works, and is much larger than a pedometer, but it's another path you could take if you're interested.
Good luck!
Der Strom
 

duda123

Member
Do you know where can I find more info about that kind of switch? That might be a little bit easier to me since it's not being easy to find a pedometer to buy :\

Edit:
I just found it!
Thanks very much :)
 
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