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| Capacitive touch/proximity buttons implementation in to PCB |
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| 3dgeo:
Hello, I want to implement 9 capacitive touch/proximity buttons in this specific PCB position (picture below – "TP1-TP8", "LOGO"). I'm noob what comes to capacitive touch buttons (I know working principle, but no practical implementation). I need it to detect finger from 5.5 mm (4 mm air, 1.5 mm acrylic) and have RGB LED in the middle of the touch pad (again, picture below) – is it possible? What I should expect if I manufacture PCB in the picture (note that I will connect all ground islands). Powered from PC USB, so power ripple shouldn't be an issue. Can NRF24L01 radio module or OLCD/IPS display interfere? What other components can interfere with touch/proximity buttons? ICs I looked to for this job: TS20 TSM12 TTP229-LSF I picked TS20 for integrated sensitivity adjustment (no extra components needed), 5V logic, comprehensive data sheet and I2C registers list, tho I don't have a clue how it will work. Sorry if my post/questions isn't very well written, as I said I'm new what comes to capacitive touch buttons. Any advice or insight will be greatly appreciated. |
| james_s:
I loathe capacitive touch buttons, they provide no tactile feedback at all and never seem to work reliably with my fingers. I think you'll have difficulty making them work with such a thick gap too, the ones I've seen have only a thin sticker or layer of plastic over the sensor pads. |
| 3dgeo:
--- Quote from: james_s on December 30, 2018, 06:05:20 pm ---I loathe capacitive touch buttons, they provide no tactile feedback at all and never seem to work reliably with my fingers. I think you'll have difficulty making them work with such a thick gap too, the ones I've seen have only a thin sticker or layer of plastic over the sensor pads. --- End quote --- Oh, I know it will not be easy, but I need them there and I'm willing to put some effort. If distance will be a problem I have other solutions – add extra PCB on top with pads or add SMD springs/standofs. Tho I would like to find out all potential issues before I order PCB samples, cos they do cost... |
| nctnico:
Look at Cypress' capacitive touch chips. They also have tools to determine the optimal design. For starters you'll need way more clearance around the capacitive touch pads. |
| 3dgeo:
--- Quote from: nctnico on December 30, 2018, 06:48:11 pm ---Look at Cypress' capacitive touch chips. They also have tools to determine the optimal design. For starters you'll need way more clearance around the capacitive touch pads. --- End quote --- Really? I think spacing is fine, this keypad has way smaller gaps and no grounding around and works just fine: |
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