Hello, I was wondering how to wire multiple sensors.
A single sensor (pulsesensor.com) uses a 5 V supply, with this kind of setup :
I want to extent this setup to 4 of the same sensors, I'm very new to electronics so If anybody could help how to wire this, that could be very helpful.
Just connect Vcc(red) and Ground(black) of all sensors to the arduino 5V and Ground Respectively. For connection multiple pins, a breadboard can be used
A breadboard has connections like this:
So to connect 4 Vcc's, insert all their pins in a single column, and use a jumper to connect it to 5V of Arduino. Do the same with Ground pins.
The third pin has to be different for all sensors, so it will use up 4 analog pins on your arduino.
Note: the pulse sensor draws around 4mA, so 4 of them will draw 16mA from your arduino, which is safe. This is not true for all types of sensors
Like this? So it's a parallel setup. Sensors act like tunable resistors right? If you put 4 sensors and thus same resistance in parallel, then the current flow through each sensor is 4 times smaller, doesn't that make the analog input signal 4 times smaller then when you use only 1 sensor?
Yes that is the correct way to wire them.
But NO they are not in parallel
they are connected to separate input pins and are read independently.
they are simply powered from the same rail.
hmm How are they not in parallel? But the voltage drops are the same for each sensor, the only thing that changes by adding a sensor is the total supply in current
to be in parallel they would all have to be connected to the same input pin which is not what you want to do.
like I said they are just drawing power from the same source.
your drawing is of simple resistors you are forgetting the third wire.
the sensors are voltage dividers .
the arduino analog pins read voltage not current.
so from the power supply viewpoint yes they are in parallel
but from the input pins viewpoint it just see's the voltage difference of each individual sensor.
I think they would be like parallel resistors, but,
If you put 4 sensors and thus same resistance in parallel, then the current flow through each sensor is 4 times smaller
Thats wrong, net resistance is 4 times smaller, so current is 4 times greater(I=V/R)....thus each sensor gets same amount of current.
