How can I bypass the touch button on fan Sencor SFE 2340WH? I want to of/off fan with smart momentary switch. Below is componets maybe with reading errors.
Components: TR1-TR5: HSDQ / BT134-800 / A2040D MCU1: SOC / SC93F8333M U1: PN6007 / M35A17
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\$\begingroup\$ What is an "inching" switch? \$\endgroup\$– JRECommented Jun 29, 2023 at 9:43
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3\$\begingroup\$ Those are capacitive touch buttons. They don't have "2 pins/contacts to imitate press". \$\endgroup\$– JustmeCommented Jun 29, 2023 at 9:54
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1\$\begingroup\$ "inching" was new to me too: it's not in Oxford English Dictionary nor Wiktionary except with the meaning of "move in small amounts" . Use for switch apparently originates with NEMA "the quickly repeated closure of a circuit to start a motor from rest for the purpose of accomplishing small movements of the driven machine.”, but now some are using it applied to switches to more-or-less mean "momentary" eg here and here \$\endgroup\$– jonathanjoCommented Jun 29, 2023 at 10:57
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2\$\begingroup\$ Okay @jonathanjo, i added picture to post higher. \$\endgroup\$– DansterCommented Jun 29, 2023 at 11:46
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1\$\begingroup\$ It’s SOC - SC93F8333M \$\endgroup\$– DansterCommented Jun 29, 2023 at 15:22
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2 Answers
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The fan will be expecting to see an AC voltage at 50 or 60Hz at the contact spring whenever you touch a pad. The voltage will be much smaller when you're not touching it. There will be very little current flowing. Unless you can find a better answer than this, you may need to experiment to see what works.
The spring is acting as a receiver, and your body acts as an antenna. When you press the button on the outside of the case, the thin plastic between the spring and your finger acts as a capacitor and all the stray electrical signals your body picks up are coupled through to the spring. The chip inside is sensitive enough to detect that.
One thing that may work is a pad placed over the touch sensor, and well insulated for safety. Maybe a flat coil of insulated wire. Connect the pad to neutral for no touch, or hot/live for a touch.
Or, if you are planning on adapting inside the case, wrap some insulated wire around the spring, and again connect that to an AC supply to activate it.
But you may well need to experiment to find how to make it trigger when you want, and not trigger when you don't.
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\$\begingroup\$ contact spring (if you meant touch button) has no voltage or i am not right? I tryied to touch it without cover, and i didn’t feel anything, so i don’t know. About your idea i don’t know what you think that i have to do. \$\endgroup\$– DansterCommented Jun 29, 2023 at 18:38
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\$\begingroup\$ @Danster I'll update the answer. \$\endgroup\$– Simon BCommented Jun 29, 2023 at 19:16
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\$\begingroup\$ And when you touch not covered touch button (contact spring) it is safe to human body as you said so there is AC voltage? \$\endgroup\$– DansterCommented Jun 29, 2023 at 20:51
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\$\begingroup\$ @Danster There's a resistor between each spring and the microporcessor. So you're probably safe. But they are tiny resistors. So safe-ish. \$\endgroup\$– Simon BCommented Jun 29, 2023 at 22:11
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Most likely, your remote sends infrared LED light signals to control the fan. You should be able to see this with your cell phone in a dark room. With an oscilloscope, you should be able to capture this signal and perhaps reproduce it yourself. If not, you may be able to order a new remote so you can try hacking the remote (the buttons on the remote instead of the buttons on the fan), which may have easier-to-hack buttons. (For help with hacking the buttons of the remote, that's a new question.) I suggested trying to get a "replacement" remote because you may go through several as you try out different ideas. If you try to mod your remote, and it doesn't work, the fan itself should remain unaffected. Hopefully, the remote buttons are resistive.
answered Jun 30, 2023 at 10:32
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\$\begingroup\$ Thanks for that idea, i was thinking about that but i want to mod fan not remote control, but thank you for help :) \$\endgroup\$– DansterCommented Jun 30, 2023 at 16:06
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\$\begingroup\$ @Danster - If you want to thank me, and my answer was worth something, please upvote my answer; we work hard for the points. \$\endgroup\$ Commented Jul 1, 2023 at 4:05
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1\$\begingroup\$ I am new here, i can’t upvoting for now. :/ \$\endgroup\$– DansterCommented Jul 1, 2023 at 7:41