Tinxy is an Indian company who is manufacturing home automation products. I recently purchased a two node Tinxy Smart Switch to see how it works and how it is designed.
In the blog, I will share my opinion about the product as well as show you the internals of the Smart Switch electronics.
There 3 terminal blocks, one for AC input and other two are for connecting the load like light or other equipment.
First thing I noticed was they have used a heat shrink tube to cover the PCB and not provided a proper plastic enclosure.
They might have done this to save the cost but I strongly think they should use a proper plastic casing which will give product a professional look and provide proper safety to the electronics as well to the person who is handling it.
For AC to DC conversion they have used a ready made power supply PCB, looks like either they designed and manufactured their own or bought from some other company.
This power supply PCB is then soldered on to the main Smart Switch PCB keeping it upside down using leads, 2 for input and 2 for output. See the image below.
They have used STMicroelectronics TSSOP-20 package Microcontroller, I was not able to read the part number properly but you can assume either it is 8 bit or 32 bit MCU.
One interesting thing I observed, they have used two bridge rectifiers D1, D2 and U3,U4 optocouplers probably to detect if AC is available on the output terminal or not, this way they can detect if the Switch is actually ON or Relay got damaged. This is a very good feature.
Two 10A relays (Y3F-105DZ) are used for load switching using a typical Mosfet drive circuit.
For Wi-Fi connectivity they have used ESP8266 module itself.
I am not sure why they used antenna wire as the module itself has the PCB antenna.
It may be that the module’s PCB antenna is not working properly as on the PCB, clearance is not given, if you see back side of the PCB, tracks are there which will restrict the Wi-Fi signals.
For powering the MCU and ESP8266 5V from AC to DC converter circuit is converted to 3.3V by linear regulator, AMS1117/3.3
Overall I found that they need to improve their product:
- their hardware design, especially the PCB layout
- and the workmanship, they need to improve the manufacturing quality.
If you have any questions please ask in the comments section below, I will try to respond as soon as possible.
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I am currently working as an embedded systems design consultant and helping companies build custom embedded products, develop test automation solution for their PCB or complete product.
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