LaundryBot 1.0

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Intro

This might be of interest to you if you want to get alerts about the state of a pre-IoT appliance based on signal from a sensor. Or maybe you just want to get started in DIY and you want some inspiration. Either way, I applaud you for taking the next step in whichever journey you're on.

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Inventing smarter appliances

In this example I'm using an ESP32 coupled with an SW-420 vibration sensor to the back of a washer and dryer to enable remote notification based on laundry room activity. This will allow us to get a pop-up notification on our device of choice with a message that will make our lives easier.

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Home Assistant

To follow this guide you will need Home Assistant running on the same network as the sensor unit. Get started by installing the ESPHome integration. The ESPHome Getting Started guide assumes some knowledge of Home Assistant which has it's own Getting Started guide.

Open source home automation that puts local control and privacy first.

There are other ways (IFTTT, Slack, Twitter) to get alerts from a sensor to your phone but these are a great topic for another excellent guide.

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Disclaimer

This guide assumes that the reader has intermediate knowledge and experience with electronics prototyping, soldering, scripting, debugging, and safe practices. As with any project there are many ways to achieve the desired result and this is just one of them. While I hope this is helpful, I offer no warranty and assume no liability for the result of following any or all of the instructions in this guide.

Materials

Here's what you'll need

• Home Assistant running on the local network

• Home Assistant companion app running on iOS or Android

• ESP32

• SW-420 Normally Closed Vibration Sensor Module

• 22AWG-28AWG stranded wire (either pre-terminated jumper wires with BLS connectors or using a BLS connector kit and crimping tool)

• half-size solderless breadboard

• USB cable

Optional

• Soldering Kit

• Perfboard

• Dust-resistant enclosure for SW-420 (I used some polypropylene cases I had sitting around)

Step 1: Set up the ESP32 with ESPHome

1. Connect ESP32 and SW-420 to a solderless protoboard or breadboard. The red LED next to the USB port on the ESP32 (in this case - a Huzzah32) is directly connected to GPIO#13. As a quick test, I connected the data line of the SW-420 to GPIO#13 to see if things were registering on the ESP32. The LED on the ESP32 started blinking when I gave the board a gentle tap. 

2. Install Home Assistant

3. Install ESPHome and continue through the steps to set up your first node.

4. Compile and upload the appropriate ESP32 yaml script (feel free to use the script shown below - substituting your info as needed) using ESPHome 

5. You may have noticed that I have this file set up for two different sensors connected to the same ESP32. If you only need one sensor you can delete the second one.

5. Once you've tested the hardware you may find that you need to fine tune the Delayed On / Off Binary Filter which will limit the sensor from registering more inputs than is actually helpful. In my application, I was seeing false positives. For instance, setting a bottle of detergent next to the dryer would register as vibration. 

I didn't want to decrease the sensitivity of the sensor, so instead I used the filter settings shown below and it helped mitigate false positives. You may have a different experience based things like environmental factors and how sensitive the sensor is.

Step 2: Build the assembly

Once you've collected all the materials, lay out the components roughly where they will be relative to one another. Sometimes I sketch out the assembly first with simplified symbols and lines showing the point to point connections. This can be helpful to avoid common wiring problems and to be able to refer back to for troubleshooting later.

Step 3: Install sensor

Install sensor in the optional enclosure and attach them to the appliance you want to monitor. 

Step 4: Adjust the settings on the SW-420

Try to trigger the sensor and adjust the sensitivity control on the SW-420 until the desired threshold is achieved. 

Step 5: Set up push notifications

Finally, it's time to get push notifications set up in Home Assistant.

1. Configure the sensor in Home Assistant in the Integrations tab (located in Settings, Devices and Services). 

2. Create an Automation (located in Settings, Automations and Scenes, + Create Automation, Create New Automation) for each sensor using the visual editor.