Helo
Could You suggest me a way to make a simple current detector which will send about 3V/50mA signal when there will be current below ~15mA/at ~12V, or just break in the circuit ?
Maybe it can be done using arduino analog input?
Cheers!
Hello, what kind of circuit do you want to monitor and what do you want to happen when it detects low or no current?
Could you post a drawing or detailed description?
This is the circuit for backup light from battery.
First is the main led light about 12v/0.5A. When current detector detect break or fall in current to about 15mA or less then it switch to backup power .
Can i use for example IC ina201 and output connect to the Arduino analog input, then write program which will send out if current drop below ~15mA
anyone ?
Fall in current from what (and what is the load). Still not very clear.
fall or break in current from the main light. The load is the main light.
What is the voltage of the back up light? How do you plan to switch it on/off? Are you using an Arduino already?
The voltage of backup light is also for 12V
Switching by relay.
You might try something like this, no Arduino needed, but you would still need a 12V - 5V regulator.
Too much... i prefer the more cheap solution, using the opamp arduino and relay but i am still not sure how to do thing with that opamp.
Looking at the ina201 datasheet you would need a shunt resistor of about 1 Ohm in series with your light, that will cause a 0.5 volt drop at 0.5 Amps from 12V to 11.5V, can your light tolerate that?
The ina202 would need a shunt of only 0.5 Ohms with just 0.25 volt drop.
If you did not use the comparator function then a 0.2 Ohm resistor in series with your light would give 0.15 volts at output of X50 amplifier when current was 15 mA, fed to analog input would give an ADC count of 30 with 5V AREF and 140 with 1.1V internal AREF, you could use an "if less than" condition to switch on your backup light.
I don't know what your proficiency level is with components, but could you use a photoresistor looking directly at the light, and set it up activate a transistor switch?