jscrane / psu

Software-controlled variable-voltage power supply with current and power monitoring

View this project on CADLAB.io.

PSU

Software-controlled variable-voltage power supply with current and power monitoring.

Features:

• Common voltages preset through web interface (In Progress)
• TFT LCD to display output voltage and current
• Digital Potentiometer for software-controlled adjustment (TODO)

Hardware

Display hardware as WifiWeatherGuy:

• Wemos D1 Mini
• PCB-mounted push switch
• 1.8" TFT LCD display
• v3 PCB (with pin headers)

PSU hardware:

• LM317 variable voltage regulator
• INA219 voltage and current sensor
• X9C103P digital potentiometer
• Old laptop transformer (19v)

Software

• Arduino 1.8.x
• Arduino/ESP8266 2.7.1
• ArduinoJson 6.15.1
• TFT_eSPI 2.2.8
• Adafruit_INA219 1.0.4
• Arduino-X9C 0.9.0
• SimpleTimer
• Stator

psu's Issues

Basic variable regulator

Basic potentiometer-controlled voltage regulator circuit:

• solder transfomer plug and breadboard socket
• lm317 + capacitors + trimpot
• connect to voltage/current sensor

connect to wifi in background

Don't wait for connection to Wifi before starting operation.

Software-controlled fuse

Mosfet circuit-breaker when current exceeds threshold

• threshold configuration
• mosfet circuit connected to gpio
• enable output after reach voltage threshold

Digital potentiometer

• add preset voltage array (float) into config.json and prepopulate with 3.3, 5, 9v
• read preset voltages and cycle between them with switch
• replace trimpot with digital potentiometer
• use Vout = Vref*(1 + RL/RH) to generate fixed output voltages, assume linear relationship between resistance and percentage argument to setPot() API
• this library looks better than the first one found: https://sites.google.com/site/tfagerscode/home/digipotx9cxx

Investigate stator library

https://github.com/PTS93/Stator

Board layout improvements

• Positioning of INA219 breakout (protrudes over edge of board)
• Positioning of C1 and C3 prevents correct attachment of heatsink to U1
  • replace heatsink footprints
  • move capacitors in
  • move U1 and Q1 out

Switch debounce

Preset voltages

• config json array
• experiment with PID controller to switch between them
• edit presets with webapp
• saving current voltage with long press of switch