Hi, I have been building since last summer an arduino weight scale using 4 pressure sensors and some hydraulic jacks.
Everything should work ok (I asked here before about a lowpass filter to deal with noise signal, tried purging air out of the hydraulic cylinders, …), but the analogread results are still very erratic. I suspect the power requirements of the transmitters are not being met: the sensors need 10-30 vdc to work with 4-20 amp outputs but I am using a 9 volts battery for the sensors and another 9v battery to power the arduino.
I would like to use an external power supply that I have from a small ta2020 audio amplifier, it says: output: dc 14.0v - 4A.
I am not sure how to proceed, other than the obvious, to try to connect the power supply to my project using the right adapter that fits the supply and then wire the +, - accordingly to my board and sensors. However I know this is wrong because the arduino works with 3.3V or 5V and this could fry my project, would a diode be enough to protect my board? and do I run the risk of burning my sensors somehow using this power supply instead of the 9 volts battery I have been using?