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Bypass touch "button"

Crazy323

New Member
Hello, sorry for my bad English but I need some help on this...

So I have a controller board from a humidifier and I want to make him smart, so I'm adding a "smart switch"

( https://a.aliexpress.com/_EyQEmC5)

This can send a pulse for 0.5s, just like the Touch of a finger, but I can't figure on the board were i should sold the 2 wires that will make the "pass"

I let u guys some pics of the board, if u can help me
20230122_195019.jpg
20230122_195058.jpg
 
Does the humidifier have a touch switch, or a momentary pushbutton, for power?

If so, which connector on the PCB does it connect to?
 
Try touching a wire short bit of wire from either the 0V (centre of 78L05) or 5V (top pin of 78L05) to the sensor terminal?

One or the other will hopefully be seen as a touch trigger.

Use a bit of thin insulated wire so holding it does not trigger the sensor.

Touch_control_mod.jpg
 
I've tried and it works perfectly, the sensor with the OV trigger the PCB on, tnks so much for the help, I was just wondering if e could get a "power supply" of 5V to power the smart switch, because it works at 5v and this board I can only read 12v on it

Sorry for the bother but I'm really newbie at this, but I like this
 
Try touching a wire short bit of wire from either the 0V (centre of 78L05) or 5V (top pin of 78L05) to the sensor terminal?

One or the other will hopefully be seen as a touch trigger.

Use a bit of thin insulated wire so holding it does not trigger the sensor.

View attachment 140065
I've tried and it works perfectly, the sensor with the OV trigger the PCB on, tnks so much for the help, I was just wondering if e could get a "power supply" of 5V to power the smart switch, because it works at 5v and this board I can only read 12v on it



Sorry for the bother but I'm really newbie at this, but I like this
 
The top pin of the 78L05 should be 5V, however it will not be able to provide much current, possibly 100mA maximum.
You could try it; if the 78L05 gets uncomfortably hot, it's too much for it.
 
The top pin of the 78L05 should be 5V, however it will not be able to provide much current, possibly 100mA maximum.
You could try it; if the 78L05 gets uncomfortably hot, it's too much for

Thank you so much for the help

So let me just see if I understand, I try the positive 5v from the top pin of 78L05 and for the negative should I use the 12v line?
 
Good evening!
I'm having the same target and i was searching like forever to find a way to bypass the touch sensor when i found this thread. I would like to use a dehumidifier within automations and it would be at least great if it would turn automatically on by connecting power as this would enable to reach the target with a smart plug.
1699297029353.jpeg

The dehumidifier is installed in my filament cabinet and is to be automated with Home Assistant.
In the long term, I would like to expand this so that I can switch on the device with an ESP8266 with esphome and recognize in which state (on/off) it is. However, I don't have the right approach for this at the moment, as I am still at the beginning with electronic circuits and am currently getting started with the help of ESP8266/32 tutorials. If it is possible and someone here could give me a nudge in the right direction, I would be really grateful.

The next step would be to add a humidity sensor and a display to the ESP8266 to show the humidity, which I have currently solved using a separate device. But I'm fine with that, as there are good instructions for it.
 
Touch sensors work either by picking up "hum" or by body capacitance shorting a signal they put on the sensor.

Try connecting a small capacitor (e.g anything around 10nF - 0.1uF) between the circuit "ground" (negative power input) and a touch contact? If that works you could use a relay or possibly even a small MOSFET such as a 2N7000 series to ground the capacitor? The connecting wire for anything but ground need to be as short as possible.

If grounding it via a cap does not work, try connecting it via eg. a 1K resistor to ground or the sense IC positive supply pin - I can't make out the IC part numbers in the photo, but the centre 8 pin one appears to be the touch interface.

The number on that IC would be helpful?

It appears most 8 pin multichannel touch sensors use an I2C interface - with data on that IC, it may also be possible to emulate it with another MCU??
 

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