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[on:]

Hi!
I am reading this but I dosn't understand it very well: http://www.pjrc.com/teensy/external_power.html
Will this battery work http://www.sparkfun.com/products/338 ? My teensy shall just blink a little when pressing on a button. (4 buttons, 4 leds).
I can not have big battery as shown on the image.

Best regards!

[Reply #1 on:]

The CR2032 is specified at 0.2mA continuous current (see http://www.houseofbatteries.com/documents/CPN-CR2032), so running LEDs off it is way over its design spec. It might just work though. You can buy these cells at many supermarkets.

[Reply #2 on:]

The CR2032 is specified at 0.2mA continuous current (see http://www.houseofbatteries.com/documents/CPN-CR2032), so running LEDs off it is way over its design spec. It might just work though. You can buy these cells at many supermarkets.

Hmm okey I see, but which battery here would you take?
http://www.sparkfun.com/search/results?term=battery&what=products

Either a coin battery or a small Lithium Ion battery.
Thanks for the help!
Best regards!

Edit: Alright if we take the leds away and just uses the button.
If a make a keypad on 4 buttons (1,2,3,4) which battery will work then? The pushed button will be saved in EEPROM storage.

[Reply #3 on:]

I think I'd try the CR2032 first. Although it is intended for low-current applications, I've just connected one to a LED using a 220 ohm series resistor, and the LED lights up fine.

The lithium ion battery would also be a good bet, but you will need exactly the right charger for it.

Just bear in mind that any lithium-based battery can decide to self-destruct and get rather hot if it doesn't like what you are doing to it.