Actions
Forum Thread Details
  • State Verified Answer
  • Replies 18 replies
  • Subscribers 306 subscribers
  • Views 2341 views
  • Users 0 members are here
Related
See a helpful answer?

Be sure to click 'more' and select 'suggest as answer'!

If you're the thread creator, be sure to click 'more' then 'Verify as Answer'!

power LED's

greenwald1818

hi,

     I was wondering, im building a raspberry pi laptop, and I need a way to tell if the battery is low. so, what part would I need to get if I get 2 LED'S, and I want the blue one to be on if the battery is full and the amber one to be on if it gets below 4.5 volts (with a 7.5 volt battery) OR if I have a multi-colored one how would I do it if the same thing applies except with a multi colored one. thx in advanced.

Parents
  • 0

    It's all about what is in your drawer for a one-off.  Another way to get the two LEDs thingy going would be to spring for a dual OC (open collector, open drain) type comparator.  One comparator energizes LED-and-ballast A, on the basis of battery level, the other comparator senses the absence of drop across load A and, in response, energizes LED-and-ballast (load) B.  Also if your design has an unused CMOS gate locally, you might want to go with the earlier solution.  EEs are an adventitious lot.

Reply
  • 0

    It's all about what is in your drawer for a one-off.  Another way to get the two LEDs thingy going would be to spring for a dual OC (open collector, open drain) type comparator.  One comparator energizes LED-and-ballast A, on the basis of battery level, the other comparator senses the absence of drop across load A and, in response, energizes LED-and-ballast (load) B.  Also if your design has an unused CMOS gate locally, you might want to go with the earlier solution.  EEs are an adventitious lot.

Children
No Data