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KingArt-N1 - Touch Light Light Switch~

This is a relatively cheap Premium glass fronted touch panel, looks clean and minimal when installed too.

Table Of Contents: * Device Features * * Breakdown * * Capacitive Touch IC * Re-Programming * * Tools * * Setup * * Programming Mode * Reference

Device Features~

  • ESP8285 micro
  • Blue status LED (micro controlled)
  • Separate touch IC controlled switch status indicators (blue and red)
  • Confirmed 10A/250VAC mains relay

front -- Image: The 1 Gang Touch Panel, featuring the glass front (protective plastic film still on)

Breakdown~

Whats in the package... This looks like a reasonably simple setup.

Removing the front glass panel you have access to the main control PCB. This holds the ESP8285 micro-controller and accompanying guff. I've worked through mapping most of the pins of interest - notes are in the images below.

The control board runs off a 5V fed from the Power-Relay board at the read of the unit - a 3v3 reg is the control board for all the logic. The back of the control board has the touch controller and the 8way header to the Power-Relay board.
There are only touch pads on the back of the control board as a means to interface with the microcontroller. There is no SonOff type programming header arrangement., see Re-Programming.

  • Control and Interface PCB front rear Sorry for the horrible pics.. will replace

  • Some Application-Interesting Pin Allocations Some Pin Allocation

*Trace for the King Art Switch with 2 (Touch-)Button is confirmed - works well with this Parameters

The Power-Relay board is reasonably simple as well.
This board, being a 1-gang switch, only has a single relay - but the PCB is set out for 3 (again, see images for trace and pin notes ).

  • Power-Relay PCB base front base rear

Capacitive Touch IC~

This board uses a dedicated capacitive touch control IC.

Something interesting, that this IC manages touch switching as well a red and blue touch status LEDs for each of the touch pads that it services as the buttons. The IC illuminates a diffuser block over a 'button', indicating: * Blue : when Idle - button state is 'OFF' * Red+Blue : when Active - button state is 'ON'

The TW8001 is also linked to a red error indicator led on the front of the Control Board - it is co-located above the EPS8285 microcontroller's Blue status indicator.

This appears to be used by the Touch IC to indicate its own state information * eg, if the touch is held for +30s the touch shows an error state (red LED) and resets - useful if you replace the front panel and it needs to recalibrate.

With regard to interfacing with the microcontroller, this device seems function with GPIO-friendly pin state for the capacitive button state reporting.

front

Here is the only information I have been able to find on this device at the time of this investigation : TechWave - TW8001.

It does have much (or: any) in way of public datasheets. If anyone finds a datasheet please link it here!

Re-Programming~

Tools~

You shall need something in way of the following: (or whatever works for you, this is just my setup) * A USB-TTL adapter (TTL, 3V3.. something also with a 3V3 source)
base rear * Some leads * A soldering iron (solder, bits.. etc) - I'm going to assume you know how/what to do with this.

Setup~

(This is my setup) USB-TTL | Lead | Board 3V3 Red 3v3 TXD White RX RXD Grey TX GND Black GND

NNB : DO NOT USE or CONNECT THE 5V ever..

base rear

Programming Mode~

Before you can program the board you have to start the ESP8285 micro in Programming Mode. This is important.

Remember we soldered the blue lead to the board at (SW) - you will use this to force the micro to the required mode on startup. (you can only do this on startup)

Entering Programming Mode: * Remove power from the board * Short the blue lead (SW) to ground (use a ground pad on the board or on your programmer) base rear * NOW: Apply power. You can remove the short to ground after a second or two.

So, Are we in Programming Mode? ...~

  • Test Failed - try again If the board has its factory firmware installed still it usually flashes the status LED on startup.. (ie: not in programming mode)

  • Test Success If you have successfully put the micro into programming mode the ONLY the blue status illumination of the touch pad will be ON.
    -> Now you can access and upload to the device using your preferred tool (Atom IDE, ESPtool, Arduino.. etc)

Remember that the flashing mode MUST BE DOUT as it is for ALL devices on which Tasmota is flashed!

Reference~

https://github.com/EphemeralPersistence/Sonoff-Tasmota/wiki