ESP8266-based smart wall switch
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README.md

View this project on CADLAB.io.

ESPurna Boards

ESPurna-H

The ESPurna-H board is a custom ESP8266-based smart wall switch. It's singularity is that it's meant to be embedded into the wall behind a standard wall switch, replacing the mechanic switch with a wifi-enabled smart switch.

The board is based on the HLW8012 power monitor IC, the same the Sonoff POW uses.

It features:

  • SPDT 10A relay with NO and NC connections brought out
  • Connections for external button and notification LED
  • HLW8012 chip for power monitoring
  • 50x50mm low profile form factor to fit in the wall switch hole

ESPurna-H Board - schematic

ESPurna-H Board - layout - top

ESPurna-H Board - layout - bottom

ESPurna-H Board - front view

Bill of materials

Item Location(s) Buy Required Optional H CPU units Total Total H
Tinkerman ESPurna-H PCB OSH Park 1 6.50€ 3 6.50€
Ai-Thinker ESP12F ESP-12 Aliexpress / Ebay 1 2.10€ 5 2.10€
Hi-Link HLK-PM01 HLK-PM01 Aliexpress / Ebay 1 2.16€ 5 2.16€
Songle SRD-05VDC-SL-C Aliexpress / Ebay 1 0.39€ 3 0.39€
AMS1117-3.3 IC1 Aliexpress / Ebay 1 0.03€ 50 0.03€
HLW8012 IC4 Aliexpress 1 0.72€ 20 0.72€
SF70E 73C thermal fuse F1 Aliexpress 1 1.20€ 5 1.20€
Fuse holder FUSE Aliexpress 1 0.06€ 100 0.06€
500mA 250V fuse FUSE Aliexpress 1 0.05€ 100 0.05€
Varistor 270V VARISTOR Aliexpress 1 0.18€ 20 0.18€
Push button RESET Aliexpress 1 0.02€ 100 0.02€
1N4148 SMD Diode D3 Aliexpress 1 0.04€ 100 0.04€
2N7002 SOT-223 N-Mosfet Q2, Q3, Q4 Aliexpress 2 1 0.05€ 50 0.10€ 0.05€
10uF 0805 tantalum capacitor C11, C12 2 0.01€ 100 0.02€
100nF 0805 ceramic capacitor C21, C22, C43, C45 2 2 0.01€ 100 0.02€ 0.02€
33nF 0805 ceramic capacitor C41, C42 2 0.01€ 100 0.02€
1uF 0805 ceramic capacitor C44 1 0.01€ 100 0.01€
0.001 2512 Ohm resistor R41 Aliexpress 1 0.03€ 10 0.03€
0 Ohm 1206 resistor R42 Aliexpress 1 0.01€ 500 0.01€
22Ohm 0805 resistor R27 1 0.01€ 100 0.01€
300Ohm 0805 resistor R28 1 0.01€ 100 0.01€
1KOhm 0805 resistor R31, R43, R44, R50 1 3 0.01€ 100 0.01€ 0.03€
10KOhm 0805 resistor R21, R22, R23, R24,
R25, R26, R32, R45,
R47, R49
7 3 0.01€ 100 0.07€ 0.03€
15KOhm 0805 resistor R46, R48 2 0.01€ 100 0.02€
470KOhm 0805 resistor R51, R52, R53, R54,
R55
5 0.01€ 100 0.05€
2 positions 5mm screw terminal Aliexpress 1 0.06€ 100 0.06€
3 positions 5mm screw terminal Aliexpress 1 0.07€ 100 0.07€
5x2 position male header 1 0.01€ 100 0.01€
Total 13.11€ 0.97€
  • (H) Optional, only required for power monitor.
  • (units) Minimum quantity for the stated price.
  • Prices are based on the cheapest option, usually Aliexpress.
  • Check the schematic (image or eagle file) for relation between parts and values.

Firmware

NOTE: PLEASE NOTE THAT IT IS A REQUIREMENT OF THE HLW8012 POWER MONITOR CHIP TO TIE THE POWER LINE TO THE CIRCUIT GROUND. THIS MEANS THAT YOU SHOULD NEVER EVER CONNECT THE BOARD GROUND TO YOUR COMPUTER WHILE CONNECTED TO MAINS. NEVER EVER FLASH THE BOARD WHILE CONNECTED TO MAINS!!

The ESPurna board is named after the ESPurna firmware which features:

  • Support for multiple ESP8266-based boards (check list)
  • Support for up to 5 different network configurations
  • Support for different types of switches and different options (pulses, synchronization,..)
  • MQTT enabled
  • Alexa integration using the FauxmoESP Library
  • Domoticz integration via MQTT
  • Home Assistant integration via MQTT
  • Support for different sensors (DHT22, DS18B20, HLW8012, current sensors, analog sensors,...)
  • Fast asynchronous HTTP Server
  • Backup and restore settings option
  • Upgrade firmware from the web interface
  • REST API (enable/disable from web interface)
  • Over-The-Air (OTA) updates
  • ... and much more

Open Hardware

Hardware designs (schematics and CAD) files are licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported License and follow the terms of the OSHW (Open-source hardware) Statement of Principles 1.0.

Disclaimer

THIS PRODUCT IS TARGETED TO EXPERIENCED USERS AT THEIR OWN RISK. THIS PRODUCT IS MEANT TO BE USED PLUGGED TO MAINS AND IT REQUIRES A DEEP UNDERSTANDING OF THE PERILS OF HIGH VOLTAGE ON HUMAN LIFE.

TO THE FULLEST EXTENT PERMISSIBLE BY THE APPLICABLE LAW, I HEREBY DISCLAIM ANY AND ALL RESPONSIBILITY, RISK, LIABILITY AND DAMAGES ARISING OUT OF DEATH OR PERSONAL INJURY RESULTING FROM ASSEMBLY OR OPERATION OF THIS PRODUCT.