I’m stuck on my project and really need some help to put it right, hope someone sees this and knows how to solve:
The brief is this:
I want to create a “status light” that is on and blue when 6.0V is detected and only turns off if the detected voltage drops below 5.9V - in which case a red light is on.
The context here is I am regulating a 2 cell lipo at 6V for an rc setup with pwm servos. The regulator itself, whilst has an indicator light, is inside an assembly - I need to be able to see it is functioning and the voltage is stable from outside this assembly.
Have been told I need a comparator LM393, an rgb 4 pin common cathode LED, a TLV431 voltage reference shunt regulator and a bunch of other components I can barely describe.
I am one or two notches above an electronics novice - this is very out of my comfort zone!
If someone could draw the circuit and show me any pins and where they go etc I’d be MASSIVELY grateful
Clever idea - I really like that kind or thinking but in this case I’m not sure how the led of the regulator performs when voltage is below 6v - the manual doesn’t specify this. My next concern with your method is whether that would be sensitive/responsive enough? Also - when I say ‘assembly’ I mean fuselage - ie I don’t mean the regulator will be hiding in a dark enclosed box per se
@siera100
Another topic caused me to dig out a piece of 1000 um Core, 2.2 mm Jacketed Plastic Fiber Optic Cable. You can use a short piece to route the LED light out to a visible location on the fuselage.
On the other hand, your comment about not knowing if the internal LED provided the information you needed about the voltage level might make this impractical.
I love these kinds of solutions, and it has made me file a little mental post-it note that wherever I need a status light, etc, in the future, flush mounting the end of a piece of fibre optic cable is far superior to an exposed LED in those cases where the status light does NOT need to be seen from any angle or far away.
Seems irrelevant now, but a phototransistor would certainly be sensitive enough, but it would be important to exclude ambient light around it and the indicator.
A small Arduino compatible microcontroller called a Digispark.
These have an internal voltage reference. It's not super-accurate, but you could calibrate it using a multimeter.
They also have an on-board regulator so it could run off the 6V power.
A voltage divider (1K + 10K resistors) could reduce the 6V down to something below 1.1V so the Digispark could measure it and switch the red & blue LEDs. You will need a current limiting resistor for the LEDs, such as 330R.
