Looking for low power battery voltage indicator

[deephaven]

I was looking for a low power battery voltage indicator. My electric toothbrush has an LCD on it to do this function, but I can't find anyone selling anything similar so I guess this is a custom design.

I'm not looking for a 'fuel gauge' necessarily, just a voltage level would do.

[Psi]

Probably not the sort of low-power you want, but could be used with a push button to active the chip and display the voltage.

[deephaven]

Thanks for the link.

I need an indicator that is permanently displaying rather than having the user do anything. So the display device needs to be inherently low power.

[T4P]

A LCD Bargraph ? They do that and it's definitely custom
You can use the 10seg led bargraphs and the LM3914 if you don't mind

[Psi]

While i love the LM3914, the problem for his application is power consumption. The chip draws a few mA while doing nothing.
So it would run his battery flat if it was active all the time.

[PA0PBZ]

Here's your LCD: [url=http://www.excel-display.com/bargraph.shtml]http://www.excel-display.com/bargraph.shtml[/url]
And here is a possible driver: http://www.datasheetcatalog.org/datasheet/philips/HEF4754VD.pdf

Not sure what you think is "low power" and what resolution you want, but yeah, it's available.

[free_electron]

http://www.digikey.com/product-search/en/optoelectronics/display-modules-lcd-oled-character-and-numeric/524437?k=lcd

pick an lcd display, drive from an ultra low power microcontroller. like an str8. St has lcd scanning code available. draws microamps...

[vk6zgo]

They call them moving coil meters!
A small analog meter won't draw a lot of current,& you can usually find extremely tiny ones in junk pieces of equipment,where they were used as audio level meters.
I think most of them are around 50uA FSD (but you can set a lower scale reading if that is too much!)
You may have to mess around with series resistors to get what you want.
Obviously,this is what you would use for a "one off" project,& if you are making thousands they may be hard to get in those quantities.
The other thing you can do,is teardown your toothbrush & steal the LCD!!

[T4P]

MSP430 can be a good candidate along with a small lcd (not graphic but those blue-on-green screens) screen

[deephaven]

http://www.digikey.com/product-search/en/optoelectronics/display-modules-lcd-oled-character-and-numeric/524437?k=lcd

pick an lcd display, drive from an ultra low power microcontroller. like an str8. St has lcd scanning code available. draws microamps...

Thanks for the suggestion. They are still a bit bigger than I was hoping for.

[deephaven]

They call them moving coil meters!
A small analog meter won't draw a lot of current,& you can usually find extremely tiny ones in junk pieces of equipment,where they were used as audio level meters.
I think most of them are around 50uA FSD (but you can set a lower scale reading if that is too much!)
You may have to mess around with series resistors to get what you want.
Obviously,this is what you would use for a "one off" project,& if you are making thousands they may be hard to get in those quantities.
The other thing you can do,is teardown your toothbrush & steal the LCD!!

We plan to make a few hundred of these, so I don't want to end up with 100's of toothbrushes - especially if you can't read their battery status