HeatPump

Arduino library to control Mitsubishi Heat Pumps via connector CN105.

Quick start

Controlling the heat pump

HeatPump hp;
hp.connect(&Serial);

heatpumpSettings settings = {
    "ON",  /* ON/OFF */
    "FAN", /* HEAT/COOL/FAN/DRY/AUTO */
    26,    /* Between 16 and 31 */
    "4",   /* Fan speed: 1-4, AUTO, or QUIET */
    "3",   /* Air direction (vertical): 1-5, SWING, or AUTO */
    "|"    /* Air direction (horizontal): <<, <, |, >, >>, <>, or SWING */
}; 

hp.setSettings(settings);
// OR individual settings
// hp.setModeSetting("COOL");

hp.update();

See heatPump_test.ino

You can make the library automatically send new settings to the heat pump by calling enableAutoUpdate(). When auto update is enabled the call to update() in the above example is not necessary, the new settings will be sent to the heat pump on the next call to sync() in loop().

Getting updates from the heat pump

void setup() {
  HeatPump hp;
  hp.connect(&Serial);
}

void loop() {
  hp.sync();

  /* get settings from heatpump, including room temperature in settings.roomTemperature */
  heatpumpSettings settings = hp.getSettings();
}

By default the library ignores changes made from other sources (usually, the IR remote) and reverts them the next time sync() is called. This is the intendend behavior when the heat pump is fully controlled by automation.

If you want to also allow manual control and allow the library to update its settings from the current state of the heat pump you need to call enableExternalUpdate(). This will also enable automatic updates.

Callbacks

Instead of manually checking settings changes on each loop, you can set callback functions to be called when the current heat pump status or settings change:

void hpSettingsChanged() {
  // ...
}

void hpStatusChanged(heatpumpStatus currentStatus) {
  // ...
}

void setup() {
  hp.setSettingsChangedCallback(hpSettingsChanged);
  hp.setStatusChangedCallback(hpStatusChanged);

  hp.connect(&Serial);
}

The callbacks will be called as necessary by the sync() method.

You can see this in use in the MQTT example.

Contents

• sources
• sample usage code
• Demo circuit using ESP-01

Installation

• PULL or download zip.
• Move contents into Arduino library directory
• Restart IDE, samples should be avaliable
• NOTE: Requires arduino json 6, older commits before 20190505 support json 5.
• If you find this all a little confusing, check out this write up blog/install by Chris Davis
  • https://chrdavis.github.io/hacking-a-mitsubishi-heat-pump-Part-1/
  • https://chrdavis.github.io/hacking-a-mitsubishi-heat-pump-Part-2/
    • Note: some people report problems with Wemos D1 due to usb serial pulling RX high when usb idle! Fix is to cut a trace, so maybe use an alternative, if following the above blog links.

Notes

• Tested with ESP8266
• Tested with Arduino Micro Pro / Arduino Nano
• Tested with Mitsubishi HeatPump MSZ-FH/GE(wall units) and SEZ-KD (ducted units) complete list

Demo Circuit

Parts

Parts required to make a CN105 female connector

• PAP-05V-S CONN HOUSING PA 5POS 2MM WHITE
  • Digi-Key Part Number 455-1489-ND
  • https://www.digikey.com/product-detail/en/jst-sales-america-inc/PAP-05V-S/455-1489-ND/759977
• SPHD-002T-P0.5 CONN TERM PHD CRIMP 24-28AWG TIN
  • Digi-Key Part Number 455-1313-1-ND
  • https://www.digikey.com/product-detail/en/jst-sales-america-inc/SPHD-002T-P0.5/455-1313-1-ND/608809
• JUMPER SPHD-001T-P0.5 X2 12" (pre-crimped alternative to 455-1313-1-ND connectors)
  • Digi-Key Part Number 455-3086-ND
  • https://www.digikey.co.uk/product-detail/en/jst-sales-america-inc/APAPA22K305/455-3086-ND/6009462

Other part suggestions

• Premade pigtails
  • https://nl.aliexpress.com/item/1005003232354177.html select 5P option
• ESP-01 module (4pk)
  • https://www.amazon.com/gp/product/B01EA3UJJ4/
• Cheap 5V to 3.3V regulator (10pk), for those that don't want to make one
  • https://www.amazon.com/gp/product/B00XAGSHY2/
• ESP-01 breakout with prewired level shifters and regulator
  • https://www.amazon.com/gp/product/B01M09B43H/

Special thanks

... to Hadley in New Zealand. His blog post, describing baud rate and details of cn105, Raspberry Pi Python code:

https://nicegear.co.nz/blog/hacking-a-mitsubishi-heat-pump-air-conditioner/

Wayback machine link as the site no longer exists: https://web.archive.org/web/20171007190023/https://nicegear.co.nz/blog/hacking-a-mitsubishi-heat-pump-air-conditioner/

License

Licensed under the GNU Lesser General Public License. https://www.gnu.org/licenses/lgpl-3.0.txt