mouse battery charger

[andrew2022]

i have a cordless mouse which takes 2 AAA size batteries. i use rechargeable batteries but its a pain keep changing them then charging etc so i was gonna make a charger to put the mouse into.

the mouse came with a desk stand which i intend on converting into a charger. main question is can the batteries be charged wile still in the mouse?

also, does any1 have a basic charger circuit. the batteries are ni-mh

 

[Someone Electro]

Yes this is fully posible!

All you do is:
-put an refinder bridge betwen the baterys and the mouses circutry (so you dont bust the mouse wen you run curent in the oposite disection to cahrge the battery)
-get some sort of conector to conact the charger on.
-get some sort of power surce to charge the battery (whith 1-3V higher votege than the batery)
-its useful to limit the curent of your power source (5-20mA)

its that simple. :wink:

 

[Someone Electro]

Oh forgot the circuit:
If you want it simple and cheap as posible you do this:
-Conect your power suply so thet the positive of your power suply is on the positive batery terminal
-If you want it curent limited put an resistor(1/2W shod do) or if you waht it good put an curent limiting circuit in (some of those voltege regulation ICs have this feture)

You cod also simply conect a wire to a comercial batery charger and run the to your mouse stand.

 

[andrew2022]

-put an refinder bridge betwen the baterys and the mouses circutry (so you dont bust the mouse wen you run curent in the oposite disection to cahrge the battery)

whats that?

the protection of the mouse circuirty is the main reason i was askin bout this

 

[Someone Electro]

Ill explayin it to you.

Wen you charge a batery you run curent backwards thru the batery to run the chemical proces in the batery backwards.If you mesure the voltege over the battery it will be like the baterys polarety changed (becose of the charging polarety)

Revese polarety can damege semiconductors and electrolic caps.

An refinder bridges output will allways be the same polarety(but the same voltege and curent ass the input)if the input polarety changes (4 diodes are conected in that way)

So wen the polarety of the mouses power line switches the refinder bridge thurns it right agen.

If you stil dont understand i will have to give you an simulatin of an refinder bridge.

by the way:How much knowlege do you have about electronics?

 

[evandude]

in case he's having trouble with your terminology, technically it is a "bridge rectifier"

and you don't need a bridge rectifier in there... when you charge a battery you are applying positive voltage to the positive terminal... if you were to apply the voltage the other way around you'd drain the battery and probably destroy it. since the positive terminal is still positive, the mouse wouldn't know the difference. true, current is going through the battery in the opposite direction but only in a loop with the charger... the current supplying the mouse circuitry would just be coming from the charger at that point, and would be in the same direction as always due to the same polarity on the supplied voltage.

 

[andrew2022]

in case he's having trouble with your terminology, technically it is a "bridge rectifier"

and you don't need a bridge rectifier in there... when you charge a battery you are applying positive voltage to the positive terminal... if you were to apply the voltage the other way around you'd drain the battery and probably destroy it. since the positive terminal is still positive, the mouse wouldn't know the difference. true, current is going through the battery in the opposite direction but only in a loop with the charger... the current supplying the mouse circuitry would just be coming from the charger at that point, and would be in the same direction as always due to the same polarity on the supplied voltage.

i do enough about electronics to do this. i also kno exactly how a bridge rectifier works. was just confused when you said 'refinder bridge'

the main thing i was concerned about was the over voltage to the mouse circuitry when the battery is being charged

 

[evandude]

it shouldn't be a problem necessarily, but that depends on how much voltage you apply. if you are real worried, you could put a resistor between the positive battery terminal and the mouse, and put a zener diode reverse-biased after the resistor to ground, rated at slightly higher than the battery voltage (when fully charged). that way you'll be limiting the voltage that the mouse sees, while charging at a higher voltage.

you'll probably want to use some sort of charging circuit with some detection so it will shut off when the batteries are charged, otherwise your batteries won't last long.

one of the coolest ideas i've seen is using an inductive charging system... you put a coil in the mouse, connected to some charging circuitry, then underneath the mouse pad (or under a special charging pad) you put a much larger coil, driven with an AC voltage. basically makes a transformer.

here's one that was done... (rather ghetto, but you get the idea)
**broken link removed**

 

[zevon8]

I may be wrong, but I believe Logitec does this with one of their better cordless mice. It has a small stand like an electric razor, and is basically a transformer connection to charge it. One half in the mouse, the other in the base. This is done with electric toothbrushes, and similar devices, since it is an elegant way to provide an electrical connection while maintaining a sealed ( watertight by necessity ) case.

The only thing I would wonder about with a larger coil for a mouse to run around on, would be any feild induced into an unsheilded mouse cord, or interaction with your monitor.

You could likely set the charging current low enough that it could be a long time frame ( trickle charge ) for a full charge, helping reduce the possibility of over charging.

 

[Someone Electro]

I seen on some site that one guy put a flat coil under the mouse pad and an inductor to charge the mouse.It worked but the coil under the mouse pad got too hot and melted the glue that was holding it to the pad and the whole thing got stuck to the flor :lol: (Hmm.. it wod be cool to have an heted mouse pad)


You proboly have 2 AA or AAA in your mouse so the charging voltege shod be 3-5 V.If you use AAA baterys you beter run a lower curent thru them (becose there smaler) or the might overhet until they pop and spill highly corosive acid all over your mouse (you dont want that to hapend)

Ni-MH baterys arnt risky of overcharging

If you dont have a lot of expirience in electronics i wod't recomend the inductor charging

You cod simply put two springs in the stand and two metal plates in the mouse (I wod also make a LED on the mouse that lits up wen the mouse charges)

Il give you a circuit

 

[evandude]

I seen on some site that one guy put a flat coil under the mouse pad and an inductor to charge the mouse.It worked but the coil under the mouse pad got too hot and melted the glue that was holding it to the pad and the whole thing got stuck to the flor :lol: (Hmm.. it wod be cool to have an heted mouse pad)

that's exactly the link i just posted...

 

[Someone Electro]

Oh didnt visit the link (yep i sen it on that site)

This guy somtimes doses REALY dumb stuf (but i like the site :lol: )

He proboly run 3-7 Amps thru that coil! :?

I wodnt make an oscilator i wod simply conect it to an mains tranfromer (got ont the can give 13A at 15V that is 195W(It was fun to fry aluminium foil whith it :twisted: ))

 

[Nigel Goodwin]

I really wish you had used a different title for this thread, everytime I see it I think of a mouse running round in a wheel, driving an alternator :lol:

 

[andrew2022]

I really wish you had used a different title for this thread, everytime I see it I think of a mouse running round in a wheel, driving an alternator :lol:

well i was gonna use a hamster to make the power to charge the mouse....


as for the inductor thing, i dont use a mousepad and there is no room in the mouse anyway.

the mouse came with a desk stand (i think a different version did have a charger in) so far i put 2 contacts on the mouse connected to the battery but that was as far as i got with it. that was about 6 month ago. so as u can see im not that desperate to get it workin.

 

[Someone Electro]

So conect it to the batery and the power suce.So it done(the chep way)


Meaby NASA is using hamsters in wheels to power there robots they use to explore mars! (thats the explanaion why they dont work somtines) :lol:

I wonder how much mW wod a hmster produce(It wod be proboly barly enugh to run an small LED)

an mouse cod produse prety much if you use an cat "turbo charger" :lol: :lol: :lol:

 

[williB]

I really wish you had used a different title for this thread, everytime I see it I think of a mouse running round in a wheel, driving an alternator :lol:

LoL me Too !!
On the https://www.otherpower.com/otherpower_experiments.html site they have a hamster with a generator hooked to his wheel.. :lol: