Dehumidifier automator

Description

I live in a small village on the edge of a large moor, in west central Scotland. We have a damp climate and so have the problem of tools and things rusting in the garage. Years ago I bought a dehumidifer to reduce this and to keep my motorbike from getting 'crusty'.

Tried a few makes and models of dehumidifers and evenutally settled on the Delonghi DNC65 as it can draw about 19 litres (the size of the water bottle in the one of the photos) per week. The problem with the DNC65 though is it's soft touch control panel and it's irregular behaviour. It will turn off randomly despite selecting differing program and timer settings.

So the goal of this project was to 1) Control the unit, 2) Monitor the environment to learn why the unit was turning off and 3) Alert me when the bottle needs emptying.

Details

So we have an Arduino Mega 2560 connected to a breakout board, which is inverted onto a veroboard. The board with the ICs and leds is the control panel removed from the DNC65.

The inputs and outputs are as follows:

- ESP8266-01 for emailing alerts
- DHT22 Humidity and Temperature sensor
- DS3231 Real time clock module
- 4 channel relay board
- 2 Buck converters (3.3v & 5v)
- 2 buttons for software assignable roles
- An RGB status led (connected to PWM pins)
- HX711 load cell amplifier connected to cheap set of digital bathroom scales
- Micro SD card adapter

The DNC65 has 5 distinct program modes and 3 timer modes.

The basic operation of the software:

Arduino startup > start sensors and wifi > flash the RGB led to indicate that the water bottle can be placed on the scales.

Select the program I want to run using the on the DNC65 control panel and then press the latching green topped button. Monitoring and controlling the DNC65 will follow using the program it was running at that point. If the unit switches off or someone comes along and selects a different program it will immediately switch it back to what it was doing (including powering on).

Actuating the switches on the DNC65 is done by momentarily setting the specific channel relay on and off - to simulate the button press.

To get the status of DNC65, the leds on the DNC65 board are read using Arduino analogue pins.

The red momentary button is used to send a status report, including today's log file (stored on the micro sd card)

For the software I used Visual Studio 2015 and the VisualMicro Arduino extension. I'll publish the software on Github if anyone's interested.

Files

20170311_182204.jpg

18cm x 12cm veroboard

JPEG Image - 3.89 MB - 04/04/2017 at 10:22

Preview

20170306_181931.jpg

Basic collection of the bits used. The SD card adapter was changed for a micro sd card adapter

JPEG Image - 3.45 MB - 04/04/2017 at 10:21

Preview

20170214_181626.jpg

First hookup to the dehumidifer, testing the relay control action

JPEG Image - 3.24 MB - 04/04/2017 at 10:21

Preview

20170212_175028.jpg

JPEG Image - 3.25 MB - 04/04/2017 at 10:21

Preview

20170204_194040.jpg

Initially had an OLED display but decided to can it as it would be used infrequently

JPEG Image - 3.40 MB - 04/04/2017 at 10:21

Preview

Discussions

Paulo Graça wrote 09/19/2021 at 17:31

I also have the same dehumidifier. And one of the things I don't like at all about it, it's when the power fails, he doesn't start automatically after when it returns. So, a remote controlled plug isn't the answer to me. So I saw your project I start wondering on how to hack it. I though using an ESP, but for home automation I recently discovered a Shelly Uni device. This device brings a webserver and also enables it to talk to your MQTT broker. Currently I'm trying to understand how both work (the dehumidifier and the shelly device) to properly control it. Since I'm out of warranty, I started thinker it. The shelly device only supports two channels, so I will use it to control the on and off and use the ADC channel to monitor the error LED (like reservoir full or out).

On the power supply board (the one that has the Relays) there you will find different voltages. You will have 220V, 14V, 5V. The push buttons board holds the 5V. I powered the device to 14V, since it accepts voltages between 12V-36V and I can remotely control the On/Off switch.

Currently I'm still trying to figure out how it works in order to have the device properly controlled.

Are you sure? yes | no

buitre-buitaker wrote 01/02/2021 at 07:44

Hi, nice project. I have this dehumidifier, and I have in mind similar idea, turn wifi the control panel. Why are you using relays to simulate button presses? What is the voltage of the dehumidifier electronics?

Are you sure? yes | no

n13ldo wrote 01/02/2021 at 09:32

Hi. Its been running 24/7 for 3 years now. Sorry I don't recall the electronic voltages on the main controller board (feeding the IO board). I went with relays because
1) Quickest way of implementing control
2) Didn't want to interfere too much with the original design of the whole dehumidifier
3) Had plenty of these small Arduino relay modules
4) Easy to swap out relays if they go bad (none have).

Failures in the 3 years:
1) First Arduino Mega2560 would occasionally hang for no apparent reason - try to code around that but ultimately replaced with a new board from a different supplier.
2) Temperature and Humidity sensor recently stopped giving humidity values - was always at 99%. Replaced with new one and back to usual (for this time of year) 60-70%
3) The DNC65 heater element does fail over time as it's probably being driven too hard when on MAX. I run the unit on ECO and still does a good job of extracting water.

Are you sure? yes | no

Dehumidifier automator

Description

Details