Hi, I am confused at options for powering a wireless mouse (diy), options are:
for 5v system:
1) 1.2 NiMH battery, step up to 5v (charger onboard with usb 5v)
2) 3.3v Mobile LiPo battery step up to 5v (charger onboard with usb 5v)
3) any other options?

for 3.3v system:
1) 1.2 NiMH battery, step up to 5v (charger onboard with usb 5v)
2) 3.3v Mobile LiPo battery (charger onboard with usb 5v)
3) any other options?

Some details for comparison of "1.2 NiMH battery" vs "3.3v LiPo mobile battery", in terms of charging, weight and life.
Also suggestions for modules and circuit for charging these above.
The reason for 5v and 3.3v is that I am building 2 mice, one now, with sensor adns 7550 (works on 5v) which is complete, expect for power source, after this i'll be making one with adns 9800 (works on 3.3v)

 

Ahh, another of my undone projects.
The lipo battery might be easier to charge but lighter (might not feel as solid).
The problem I had with the wireless mouse was that I always forgot to turn it off so the battery would go dead. What I was going to make was a wireless charger for my wireless mouse, but I went back to a wired one before I did the project.

 

My wife works in accounting and is always using the mouse. At this rate we're going through batteries at one per week. It's at the point now where I'm just going to go back to a wired mouse, even if it does get tangled up in the cabling

Michael Lalonde
Sudbury, Ontario

 

Ahh, another of my undone projects.
The lipo battery might be easier to charge but lighter (might not feel as solid).
The problem I had with the wireless mouse was that I always forgot to turn it off so the battery would go dead. What I was going to make was a wireless charger for my wireless mouse, but I went back to a wired one before I did the project.

Yep I understand, I am trying to let it be not unfinished.
Well, as I have heard NiCD is safe and easy to recharge and has no memory effect.
For LiPo or Li-ion does it have memory effect, if it does, how does charger take care of it?

 

You may want to look at the internal workings of the mouse that you already have. The two main midifications would be...
1) Change the timing capacitor to decrease the time it takes to go into stand-by mode.
2) change the op Amp (comparitor) to ultra-low-power version.

For #2, some devices have low-tech motion sensing switches that power a comparitor and charge the timing capacitor. If this comparitor consumes too much power (or if the voltage divider used fr the voltage reference consumes too much power, then battery life is low). Some op amps use less than 10 micro amps in standby mode and have high enough input impedence to allow multi-mega ohm reference voltage. e.g. TLV2241

If an op amp is not used and Microcontroller is used instead, then there is not much you can do to reduce power consumption. A more expensive (Logitech) mouse may be better.

Also, learning some keyboard shortcuts also help so you or your wife are not touching the mouse so often and taking it out is sleep mode. As you said, if she is an accountant and jumping from cell to cell in spreadsheets, then that may not be possible. A better quality mouse may be the answer - out staff uses Logitech and I don't think anyone changes batteries more than once per month.

 

Unless you want to slow charge the nickel batteries they are hard to charge:
http://www.powerstream.com/NiMH.htm

Lipo's on the other hand are pretty easy. Just set the voltage to 4.2 volt/cell and limit the current to a safe level. Neither one like to be discharged past a certain point. I don't know if your circuits have a cut off for low voltage.

 

Slow charging is not a problem,
My issues are
1) safety, no blowing of batteries
2) ease of circuit-ing, my mouse would be both wired as well as wireless, even both at a time. I would want it to be easily made of existing charging modules so any suggestions regarding the circuit and modules , for power part only.

 

This IC might do it.

http://cds.linear.com/docs/en/datasheet/1980f.pdf

 

Thanks,
I am now taking a different approach, since I allready have a micro controller, and charging is going to be done when connected to a power supply, why not make your own charger.
Also ic's are difficult to get here.
Nimh seems to be easy to charge, but lipo system can be used for other projects too.
So now I would require help with this, if any one can provide me with cuircuit to detect the capacity of battery connected (if it can be done) and current control for c/10 trickle charging. Also how to charge nimah, lipo and li ion details like what happen when we want to charge in between.

 

Nimd is easy if you use C/20 and 1.45 volts you don't need to turn the charger off.

Lithium is easy because you can set the voltage to 4.2 volts and limit the current.

The problem you will have building your own is that you only have 5 volts from the usb to charge with. The easy to find regulators need a few volts above 4.2 to regulate.
I don't know a way to determine capacity.

 

Thanks,
You are right, lithium does have modules easily available, but for nimh I might have to build one.
I am not sure how safe lithium is if its used in diy.
Ill also see if I can source some thing from mobile repair shop for lithium else its nimh with homemade voltage and current regulator.

 

My choice would be the lithium. The nickel will not be as reliable because the charge won't be good.
Good idea about the mobile shop.

 

I think you're right, so I'll be going with lithium
Atleast there are modules available. All I need now is to know how to control it.

 

If you have a friend at the mobile shop you might be able to get the board from the phone as well as the battery. Most of them charge from a USB port.

 

No friends there but I think I can get some boards or ic or parts and then challenge myself to find right pinouts
That would be most probably 3v system, would need stepup to 5v.

 

Here is a simple charger. It uses a TL431 shunt regulator. Since you can charge lithium with a constant 4.2 volts at c/10 + it limits the current from the USB with a 10 ohm resistor. When the voltage reaches 4.2 volts the TL431 turns on and shunts the current thru it instead of the battery. The TL431 is pretty common so maybe you can find some.

 

Ah, thank you.
This would really help. I am really bad at electronics, only thing that keeps me here is programming , I understand computer logic systems only