Testing has been put on hold - RECREATE AT YOUR OWN RISK

FURTHER IMAGES TO BE ADDED ASAP!

3D printed enclosure files to follow soon!

Homini AC Powered Relay (2) Module - OTA Firmware Updates Enabled

Brief Description

This ATmega328p based board has been created to enable wireless switching of 2 devices, was designed for lighting needs, but pretty much any 240v AC powered device will work. The finished product will be enclosed inside of a 3D Printed casing, allowing access to the screw terminals only, no chance of any accidental interference with it being High Voltage of 240/250VAC.

This device has been designed to be installed in ceilings for connection to ceiling lights, however you could use this outside of this application but either enclosure the device in a container that stops any access to the live power entering the board and even the screw terminals. Even though my finished enclosure will enclose this module, the input power cable will still be accessible along with the screw terminals. Not safe to be around personal, especially children as there will also be no strain relief on the cables.

As the module is running with an external 16MHz crystal, we are able to use MYSBootloader to enable us to use OTA Firmware Updates, saving you from having to physically get the module for a software/firmware update. The module has been designed to work with UK Mains, so it has a Live and a Neutral input. The module itself is self-powered from the mains power input and is fused with a slow blow and thermal fuse on the main input meaning any short on the board for any reason will cause the slow blow fuse to cut and any heat increase inside of the enclosure will cut the thermal fuse. Alongside of this, the relay channels are also protected with a 2A re-settable fuse themselves, meaning that any issues with the connected devices pulling any more than 2A will automatically cut out. We have also allowed the use of a ATSHA204 hardware signing and current sensing using a ACS712 chip. Lastly, we have the option to attach two switches to the device to switch the attached devices on-board rather than using wireless switches or automatically switching the devices. This allows us to route a switch to the device just like a normal light switch would.

AC Safety Implementations

• 250VAC Varistor
• Slow Blow Fuse
• 73 Degrees Thermal Fuse
• 2 x 2A Fuses on Relays

Physical Dimensions

• Height: 25mm
• Width: 50mm
• Length: 50mm

Connectors

• 1 x 2pole 5mm Spacing Screw Terminal for AC Input
• 2 x 2pole 5mm Spacing Screw Terminal for Attached Devices
• 2 x 2pole 3.5mm Spacing Screw Terminal for Attached Switches
• 1 x 6pin 2.54 Spacing FTDI Connector
• 1 x 6pin (3x2) 2.54 Spacing SPI Connector

Radio

• nRF24L01 Radio Transceiver to communicate to MySensors gateway

Power Supply

This device is self-powered through an on-board transformer using the 240VAC Input to step down to 3.3V. DO NOT USE 5V, NOT EVEN FOR PROGRAMMING.

Software

Bootloader

MYSBootloader running at 16MHz External Crystal to enable the use of OTA updates.

Controller

My primary controller is OpenHAB2 but as this does not support OTA for MySensors, we're able to install MyController alongside of your normal controller. For now, use the install instructions of MyController on their website with one slight difference, change the port that is used from 8443 to anything else you desire (probably safe to use 9443 or something alike).

FUSES

• low_fuses=0xF7
• high_fuses=0xDA
• extended_fuses=0x06

Testing

1. High Voltage testing - COMPLETED
2. MySensors OTA firmware update testing - COMPLETED
3. 2A Load for each relay testing
4. Fully loaded relays inside of enclosure ventilation/overheating testing

TO-DO List

1. Create build instruction (written and possibly video)
2. Create 3D Printable enclosure
3. Develop software to make use of ATSHA Signing
4. Develop software to make use of current sensing
5. Develop software to make use of on-board switches
6. Address current sensor placement

Function

Allowing the wireless switching of two AC powered devices. Maybe to switch Lighting, Ceiling Lights.

Issues

1. The SPI Connector is having to be soldering from the same side as mounted as the transformer is covering the other side of the through-holes. I have plans to use POGO Pins for the SPI connector, if that changes I will change the SPI connector to be surface mount instead.
2. The current sensor is attached to only one relay, need to address this to attach to the input before it splits to the two relays.

Appreciations

Jkandasa on Mysensors forum for developing the MyController software

Tekka on MySensors forum for developing the MYSBootloader files.

I'm very interested in all of your variations, improvements and applications of this module, please add them to the comments with pictures and/or Videos.

Disclaimer

I do not advise you in any way to make/install this product into a property and therefore I take no responsibility for any issues, problems you have or even health implications that you endure while completing the installation or even using the product after installing. BUILD, USE and INSTALL ARE YOUR OWN RISK

Licensing

This product is licensed under the CC-BY-SA OpenHardware certificate. For more information please see https://creativecommons.org/licenses/by-sa/4.0/