Hello everyone, I am new to arduino and electronics and I am going through a steep learning curve.

I am using an Arduino MEGA 2560 rev3 with a terminal block adapter and I am trying to build a DAQ system. In the system there are circuits using 5v, 12v, and 24v.

• I am using 12v into the Vin to power the board and have connected the GND on the arduino to the GND of the 12v supply.
• I am powering 7x MAX31865, 2x NAU 7802 chips, and 2x DFRobot High Temperature chips in parallel with the 5v pin of the arduino and grounding them back to the arduino GND.
• I am powering 9x intrinsic barriers that connect between the 7x MAX31865 and 2x DFRobot chips and their sensors, as well as a relay that uses 24v, using a 12v to 24v converter for power. I have grounded the barriers to the 24v ground and the relay to both the 24v ground and arduino ground.

Currently the setup works well and I can read values properly. But I noticed that the arduino's 5v voltage regulator gets really hot (most likely due to powering many chips) which I would like to avoid. I am trying to power the chips through a 12v to 5v converter instead with a higher power rating. When I wire it, everything powers normally but the readings I get are all messed up.

I am suspecting that it has to do with grounding of the 5v circuit (signal lines are going to arduino board but power is through 5v conveter) but I am not sure what is wrong. When I connect the 5v side or the 12v side of the converter ground to the arduino ground it still does not fix the problem. Below is a simplified sketch of the full scale wiring diagram that depicts the way that the powers and grounds are wired. It excludes most chips but the idea should be there.

Any input would be greatly appreciated!

 

Hello everyone, I am new to arduino and electronics and I am going through a steep learning curve.

I am using an Arduino MEGA 2560 rev3 with a terminal block adapter and I am trying to build a DAQ system. In the system there are circuits using 5v, 12v, and 24v.

• I am using 12v into the Vin to power the board and have connected the GND on the arduino to the GND of the 12v supply.
• I am powering 7x MAX31865, 2x NAU 7802 chips, and 2x DFRobot High Temperature chips in parallel with the 5v pin of the arduino and grounding them back to the arduino GND.

Currently the setup works well and I can read values properly. But I noticed that the arduino's 5v voltage regulator gets really hot (most likely due to powering many chips) which I would like to avoid. I am trying to power the chips through a 12v to 5v converter instead with a higher power rating. When I wire it, everything powers normally but the readings I get are all messed up.
Any input would be greatly appreciated!

The 5V regulator on the Arduino Mega is very small and has no heat sink. With 12V as an input source, it is dissipating 7V x the total Mega current which s probably very near to its maximum power dissipation. That's why it gets hot. Drop the 12VDC with a LM7805 regulator and connect its output to the 5V input of the Mega. If that gets warm, you can easily add a small heat sink to it.

 

For best results, use the negative terminal of the 12V power source as a common ground point for all the devices, including the Arduino.