Small low battery indicator

[Mooper]

This is daftmike's low battery indicator mk2, I just made it smaller. Thought I would share.
Original post

V2 uses an adjustment pot to allow you to set the low voltage level more easily.
Here it is: https://oshpark.com/shared_projects/3m831fzw

Dimensions: 0.56x0.51 inches (14.12x12.90 mm)


Here's V3: https://oshpark.com/shared_projects/JM1rsFmC

Dimensions: 0.45x0.38 inches (11.40x9.73 mm)

V3 requires you to do a bit of math and some tight soldering. The pot is replaced with 2 resistors. If you know at what voltage you want the LED to go from green to red, just plug it in to the formula.

0.6v=Vlow*R2/(R1+R2)

OR forget the formula and just change the underlined portion of this url to your desired low voltage level.

https://www.wolframalpha.com/input/?i=0.6%3D10.6*x%2F(10000%2Bx)
Start with 10k for R1.
X will be R2

V3

 

[bentomo]

Nice Job,

keep in mind it's nice to try and keep orders above $5 on oshpark because they do free shipping and they get a teeny tiny profit margin at that point.

 

[Mooper]

Deleted horrible first design. Updated first post with 2 others.

 

[Aurelio]

That's really cool and small. I will surely use one in my portable. Thanks for sharing