Here is another teardown and this time it is a HomeMate FAN Touch Controller.
Touch FAN controllers are revolutionizing the way we control our home environments. These innovative devices replace traditional fan switches with a sleek and responsive touch interface, offering several advantages:
- Enhanced Convenience: Operate your fan with a simple touch, eliminating the need for physical buttons.
- Multi-Speed Control: Adjust fan speed effortlessly through touch gestures, creating a comfortable atmosphere.
- Smart Home Integration: Connect your touch controller to popular smart home platforms like Alexa or Google Assistant, allowing for voice control and automation.
I got it for amazon for about 1000 INR. It comes in a small packing box along with a Manual explaining how to operate and how to do the electrical wiring.
This Fan controller is relay based and not TRIAC based, it has five speed mode. User can control the FAN Speed via Touch or with the help of an App connected over Wi-Fi.
Now let us see how it looks like from the outside, it front panel and connection terminals.
You can use a simple screw driver to open the cover. There are no screws, it is just press fit. Although, I opened it by removing the front panel.
You can clearly see LEDs with side view and three Touch Pads, basically these are plastic pads which will allow LED light to spread. We cannot place led below the pad else touch functionaly cannot be given.
On the right hand side LEDs are there to show the current speed setting.
You can pull the whole circuit out easily and you will see the whole contruction.
Honestly I don’t like the way different PCBs are hard soldered. This is not at all mass manufacturing and repair friendly.
I would have done it differently using proper headers and if high volume is there we can also got for Rigid flex PCB design.
Now let me show each PCB separately so you can see the details.
As expected the main controller with Wi-Fi is Tuya’s CB3S.
Not sure why they had to use an external EEPROM (24C02), settings could be stored the internal Flash itself and nothing will happen with multiple writes over a life time of 5-7 years. There are clever ways to manage that with a set of memory locations and keep rotating it.
INL2003, its a Darlington-pair driver IC with 7 channels, 5 are used for the circuit.
For touch, Cypress Semiconductor’s CY8C4024 microcontroller is used which has one of the best capacitive touch sense controller, as they claim. The capacitive touch is available on each of the MCUs pin and Cypress provides lot of documentation and software to easily understand and configure it.
I am wondering if such a high-end controller with touch was really required. There are other ICs available which gives dedicated multiple capacitive touch pads sensing facility.
if you remove the main controller board, you will notice a ready made AC to DC (5V) module power supply is used and soldered upside down on another PCB.
It’s a Hi-Link’s Open Frame Power Supply Module, 5V at 5W.
some more images of the power supply is here:
once you remove this power supply module, what you will get is a PCB which has a large slot cut inside. It has various high power resistors, MOV and LDO(5V to 3.3V), I have no ideas why someone should put the LDO here 🙂
High power Resistors are part of the snubber circuit used on Relay contacts.
If you remove this PCB, you will see the last PCB which has the relays.
SWIX brand Relays are used, ever heard of them.
Coil is powered by 5V @ 0.36W and the contact rating is Typical 230V AC at 5A, must be capable of up to atleast 277V AC.
That’s all. I hope you liked this teardown blog and learned something new today.
I am currently working as an embedded systems design consultant helping companies build custom embedded products and develop test automation solutions for their PCB.
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