Summary

This thing was made with Tinkercad. Edit it online https://tinkercad.com/things/g1vFJBOX838

Use this to monitor 2 power supplies ,both volts and amps Two temperatures, extruder and print bed in both Fahrenheit and centigrade. Two LEDs indicate power to heaters.
The. Arduino code is in thing files

Instructions

I used a 2004 LCD display, 2 DS 18B20 temp sensors, 1 AC-712 5 amp sensor,1 AS-GY-712 20 amp sensor, a Moderndevices RBBB UNO clone, 2 voltage dividers made of 1-10k resistor & 1- 20k trim pot, 2 LEDS and a few connectors. Then I created the code in Arduino a little tweaking here and there and this is the result. The extruder temp is low because the sensor just rests on the top of extruder so this is just a reference reading not actual temp (DS 18B20 only reads to 125 C). In the code is a place I added a fudge factor to get a better idea of extruder temperature there is one for bed temp also.
The bed sensor is stuck to the bottom of the bed heater. The 2 LEDS are connected to the heating elements wiring, they indicate when power is flowing to the heaters (good for trouble shooting heater problems & I just like blinking LEDs). I use 2 separate power supplies, one for the Arduino,stepper motors, fans and lights . I used solid state relays for the extruder heater and the bed heater they have their own power supply . Neo magnets hold display case to cabinet so I can position it as I need. Arduino code is included in thing files

3D Printer Monitor Volts Temperatures Amperes 2 of each with Arduino code