I need a measure of voltage between supercapacitor terminals. voltage soure and s.cap(supercapacitor ) in serius. I want the actual voltage of s.cap relative to the ground using Arduino.
I did try to measure the voltage using an Arduino voltage sensor but it is not actually(n1 nod voltage = Soures' voltage + super cap voltage). How do it? Plz
Do you have a schematic for the "voltage sensor"? I assume it's just a voltage divider?
You can use two voltage dividers into two analog pins, and subtract.
...The arduino always reads relative to its own ground. If the Arduino is battery operated and isolated you can use it like a multimeter and connect it between any two points, as long as the analog input is positive relative to its ground and the difference doesn't exceed 5V.
What is "bulbe"? What is its resistance and purpose? That "voltage sensor" must have 3 or 4 wires, 2 to 24V + and ground, and 2 to Arduino GND and analog in pin.
Do you have a voltmeter? Do not connect that sensor to the Arduino until you KNOW the voltage at the sensor pins!
Set up two dividers, such as the one shown, then measure both terminals and subtract the - from the + and you will have the super cap voltage at that point.
There are 3 occurrences of "S" on your diagram, which one is connected to A0?
R1 and R2 are relay modules. And S is the signal to modules.A0 is connected to the voltage sensor.
I try to develop a Supercapacitor Assitis LED system(SCALED System).
When charging and discharging path control by using Relay modules as switches.I measured the voltage of S.Cap. LED bulb is serious with s.cap. I want to bulb is always on. (charging and discharging )
I did try it. it is the charging loop is working but the discharging loop is not correct.
You need to increase your impedance (divider resistors) and add something in the range of 100nF to the A/D input to make up for the A/D load (charging of its internal node).
You can also use a op-amp connected as a unity gain amplifier. IE for a buffer to the A/D and go into the megohm resistor range. the - input of the op-amp is connected to the output. I usually make this connection with a 10K resistor. Most any op-amp would work but rail to rail on powered by your VCC would be the best.
Ok, Sir try to do it. Can I Use Optocopler to measure voltage?
Yes but. That would involve some complicated analog circuit design and expensive couplers. The initial problem is still there how to read the voltage at the source. Is it practical probably not.
You have not shown how the arduino is powered.
AS @DVDdoug says, you would need a connection between the arduino 0V and the 24V supply 0V.
You need to know the resistance across GND and VCC inputs, its NOT a voltage sensor, (which would be infinite impedance) as a potential divider its actually a current sensor.
What is the purpose of bulbe?
What is the voltage rating of your "supercapacitor - can you provide a link to the data?
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