💡 Sonoff Slampher v2 flashing with ESPHome

📖 Summary

So in this tutorial I'll show the following steps to reproduce the flashing of Sonoff Slampher v2 and an optional step requiering a 3D printer in order to print a custom case for the board

1. Opening the Sonoff Slampher
2. Locating required pins to solder on
3. Setting up your YAML file
4. Flashing the board with esphome
5. Pairing the board with your home assistant
6. Optional: Printing a custom case for the board

📋 Prerequisites

• ✅ Sonoff Slampher v2.x
• ✅ Soldering iron is strongly recommended to secure the connections
• ✅ Philips screwdriver
• ✅ Your favorite text editor
• ✅ ESPHome installed on your machine
• ✅ USB TTL Serial Converter (like this one)

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1. 🪛 Opening the Sonoff Slampher

The first step is to open the Sonoff Slampher.

1. Unplug the Sonoff Slampher from the power source and wait for at least 10 minutes to discharge the capacitors
2. Locate the two screws on the top of the case and remove them with the Philips screwdriver

Lift the case up and make sure not to lose the screws and don't force the case off, it should come off easily. Wires are pretty strong, but don't pull them too hard. If you plan to repurpose the board as a smart switch, you can cut the wires to the desired length or desolder them from the board/sockets.

2. 🔌 Locating required pins to solder on

The next step is to locate the required pins to solder on.

You'll need to find 5 pins on the board to solder on.

Pin	Description
GND	Ground
3V3	Power
RX	Data (receiver)
TX	Data (transmitter)
GPIO 0	Reset on R3 unpopulated pad

Here's a picture where you can find them:

I suggest you soldering Dupont connectors to the board in order to have a more secure connection and easier to (re)use.

Then solder a jumper wire to the R3 that can be connected to the USB TTL Serial Converter's GND pin in order to be able to start the board in flashing mode.

Once you've soldered the pins, you can connect the USB TTL Serial Converter like so:

Pins from the board	Pins from the USB TTL Serial Converter
GND	GND
3V3	VCC
RX	TX
TX	RX
R3 (GPIO 0)	GND

3. 📝 Setting up your YAML file

The next step is to setup your YAML file.

You can download the sonoff-slampher-example.yml from this repository and edit it to your needs.

Here's what you need to change:

🔧 General settings

The name of the device and its friendly name for Home Assistant.

esphome:
  name: <your-device-name>
  friendly_name: <your-device-friendly-name>

🔐 Authentication settings with Home Assistant

The encryption key and the reboot timeout that will be used to authenticate the device with Home Assistant.

api:
  encryption:
    key: "MZjX7hoxB43MeKI8MsLdKTjzduEUjRU9sH4TGtFCmKX="
  reboot_timeout: 0s

📦 OTA settings

The OTA (Over The Air) settings are used to update the device firmware from the ESPHome dashboard.

ota:
  - platform: esphome
    password: "de82ddbe2bebb6010a721fd2451684d6"

🛜 WiFi settings

The WiFi settings are used to connect the device to your home network.

wifi:
  ssid: "<your-wifi-ssid>"
  password: "<your-wifi-password>"
  min_auth_mode: WPA2 # Required for next ESPHome updates. Please check the ESPHome documentation for more details.

📡 Access Point settings

The AP settings are used to create a local access point for the device if the WiFi connection is not available.

ap:
  ssid: "<your-ap-ssid>"
  password: "<your-ap-password>"

For the rest of the file, you can keep the default settings provided in the example file.

4. 💻 Flashing the board with esphome

Here you have two options, you can either use the ESPHome CLI or the ESPHome dashboard inside your Home Assistant instance.

Since I'm have issues with the ESPHome dashboard inside my Home Assistant instance, I'll use the ESPHome CLI to flash the board. But I'll show you how to do it with the dashboard as well.

First of all make sure your board is in flashing mode by connecting the USB TTL Serial Converter to the board and the GND pin to the R3 wire that you soldered on as well as the other pins as explained at the end of the 2. 🔌 Locating required pins to solder on section.

📦 Using the ESPHome CLI

1. The first step is to install the ESPHome CLI.

   # Using python
   pip install esphome

   # Using brew on macOS
   brew install esphome

   # Using apt on Ubuntu
   sudo apt install esphome

   For other operating systems, please check the ESPHome documentation for more details.

2. Connect the USB TTL Serial Converter to your computer and the board to the USB TTL Serial Converter.
3. Type the following command to flash the board:

   esphome run <your-yaml-file>.yml

4. Wait for esphome to download all dependencies and select the correct board and port (generally pick option 1).

5. Wait for esphome to flash the board.

If everything went well, you should see the following output: INFO Successfully uploaded program.

6. Once the board is flashed, you can unplug the R3 wire from the GND pin and disconnect/reconnect the USB TTL Serial Converter in order to setup it in the Home Assistant configuration.

🏠 Flashing the board with the Home Assistant ESPHome integration

1. Open your Home Assistant instance and go to the ESPHome Builder tab.
2. Click on + New device on the bottom-right corner and select Import from file and select your YAML file created.
3. Click on INSTALL and wait for the device to be installed.
4. Select the board from the list of devices.

🔗 Pairing the board with your Home Assistant

If everything went well, you should be able to add the device to your Home Assistant instance. You'll need to copy the API key from the device settings and paste it in the Home Assistant configuration.

1. Open your Home Assistant instance and go to the Devices & Services section.
2. Your new device should automagically appear in the Devices & Services section. Click on Add

3. You'll be prompted to enter the API key. Enter the API key you copied from the device settings and click on Submit.
4. Now you're good to go! You should be able to control the device from your Home Assistant instance.

6. 🖨️ Optional: Printing a custom case for the board

If you want to print a custom case for the board, you can use the sonoff-slampher-case.stl and sonoff-slampher-cover.stl files from this repository. You can also download the Fusion 360 file from this repository and open it with Fusion 360 to edit the design.

You'll be able to reuse the original screws to close the case.

Here's some parameters used to print the case:

Parameter	Value
Filament type	PLA
Filament color	White
Filament brand	Amazon Basics
Bed temperature	50°C
Hotend temperature	200°C
Print speed	150mm/s
Layer height	0.28mm
Support	Yes

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