Replacement Module PCB | Home Automation Tech Blog

Fun with Embedded Electronics

Replacement Module PCB

Having had some Home Control ZWave modules for some years, a few of them have recently failed. I also have a few lamp modules but because I no longer use incandescent lamps I needed a way to reuse the modules. You can see the failed IC on the right.

20160919_073555

My new Home Automation system is Node-red based and having read all of the articles by Peter Scargill on his Tech Block (http:tech.scargill.net) I decided to redesign new replacement electronics for the modules and run with the MQTT software that Peter and his good friend Aiden have been working on. Having used Peter’s old APPCON system in the past I was well aware of his technical skills when it comes to getting something reliable.

The design is based around the ESP12E modules and the bonus of the using these is that they are very cheap, especially when you consider you get a complete 32 bit processor module WiFi for this low price. These modules can be found on the likes of eBay or AliExpress.

The design consists of 2 boards. A power and relay PCB and a processor/wifi PCB. This keeps with the original design and gives me an ON/OFF button. I have added an LED to this design so I have a status indicator. There is also a temperature sensor, DS18B20 on this board so I can monitor the temperature internally.

The power supply is a proper AC-DC switching supply with 5V output at up to 700mA. This is dropped to 3.3V for the ESP12E via a small linear regulator. I have some lamp modules from Everspring that have a cheap resistive capacitor dropped type supply and it fails when the AC input in my home drops to 209Vac. This AC-DC module is specced for 86 to 264V input so should be much better.

20160919_075319

The ESP12E modules are SMD so you need a good soldering setup to do them but it is not difficult if you take your time.

20160919_075707

I’ll post the design files for this board when I have had the chance to test them in a few weeks time but here is the 2 PCB designs showing the layout.

pcb-mqtt1

This image shows the 2 PCB’s assembled in the 3D CAD software.

mqttswitch

For the replacement lamp modules I created a PCB the exact same dimensions as the old one and then put the relay and power on the top side and the ESP12E on the underside of the board. There is an LED on the original so I used the same type for this design.

everspring

Update 2nd Oct 2016

The PCB’s arrived. Read about it here.


Post a Comment