Refrigeration C++

License

This project is licensed under the MIT License. See the 'docs/LICENSE' file for details.

Third-Party Licenses

This project includes third-party software:

• OpenSSL (Apache License 2.0) — see vendor/openssl/LICENSE.txt
• ws2811 (MIT License) — see vendor/ws2811/LICENSE
• FTXUI (MIT License) — see vendor/FTXUI/LICENSE
• nlohmann/json (MIT License) — see vendor/nlohmann_json/LICENSE.MIT

All third-party licenses are included in the source distribution. See 'docs/THIRD_PARTY_LICENSES' for details. When redistributing or packaging this software, be sure to include all relevant license files.

---

This is my software to control a refrigeration system with a Raspberry Pi.

---

Compilation

Base System

sudo apt-get install libssl-dev build-essential gcc make g++-aarch64-linux-gnu
# Build the project (OpenSSL and FTXUI are built automatically if needed):
make            # Build everything except server (.deb, OpenSSL, FTXUI)
make clean      # Clean build folder (preserves vendor builds: OpenSSL, FTXUI)
make clean-all  # Clean everything including vendor builds

Note:

• make automatically builds OpenSSL and FTXUI on first build or if they're missing.
• make clean preserves vendor builds to avoid unnecessary rebuilds.
• make clean-all completely cleans everything including vendor builds.

Installation

1. sudo raspi-config
   • Enable 1-Wire, I2C, and SPI, then reboot.
2. Install the .deb file.
3. Run sudo tech-tool to set up the device.

---

Startup Behavior

On startup, the system will broadcast a hotspot for 2 minutes (or as long as you remain connected).

Force Start Hotspot

Set the setpoint to 65°F and press and hold the alarm button for 10+ seconds. The IP address will display on the inside screen. The hotspot remains active for 2 minutes unless you stay connected.

---

Alarm Codes

Shutdown Alarms

• 1001 - Unit not cooling (≥5°F across coil in 30 min & Return Temp > 30°F)
• 1002 - Unit not heating (≥5°F across coil in 30 min & Return Temp < 60°F)
• 1004 - Unit defrost timed out (defrost > 45 min)
• 2000 - Return sensor failure (out of range)
• 2001 - Coil sensor failure (out of range)
• 9001 - Pretrip cooling issue
• 9002 - Pretrip heating issue
• 9003 - Pretrip cooling issue #2

Warning Alarms

• 2002 - Supply sensor failure (out of range)
• 9000 - Pretrip passed

---

Setpoint Options

• Buttons:
  • Press/hold either button for 2s: display flashes setpoint.
  • Use up/down to adjust. Hold >5s to skip by 5.
  • Press alarm button to save and exit.
  • Inactivity exits without saving.

---

Demo Mode

Set setpoint to 80°F and hold the defrost button for 10s. Toggles Demo Mode (simulates cooling, heating, defrost, etc.).

---

Pretrip Mode

Set setpoint to 65°F and hold the defrost button for 10s. Starts Pretrip Mode (simulates cooling, heating, and returns to cooling before pass/fail).

---

GPIO Pins Used

Function	GPIO Pin
Compressor Output	17
Fan Output	27
3-way Valve Output	22
Electric Heat Output	23
Alarm Button	5
Defrost Button	6
Up Button	25
Down Button	16
LED Lights	18
SDA	2
SCL	3
One-Wire	4

---

Required Equipment (WIP until fully built and tested)

• (1) Raspberry Pi
• (1) Headers
• (1) DS18B20 sensors
• (1) Enclosure
• (1) 17 pin connector
• (1) 20 conductor cable
• (1) Weather Box Back
• (1) Relay Din mount
• (1) Buttons All
• (1) I2C 2004 LCD
• (1) Step Down Transformer 24V-5V
• (1) Addressable LED's
• (1) ON/OFF switch
• (1) (Optional) ADS1115

---