How to replace finger touch when using capacitive touch screen?

Thread Starter

Dimension

Joined Feb 20, 2024
2
I have a capacitive touch user interface that controls a pump. When I touch the START icon of the user interface screen, a pump starts and runs for 1-hour. After 1-hour the pump turns off. To turn it on again, I must touch the START icon again. I do not want to have to physically touch the START icon every time I want to start the pump. The user interface is connected to some type of controller that runs the pump. I MUST use the setup as it is and cannot bypass or utilize some other electrical/electronic control. What I would like to know is, is there a very simple way to simulate the finger touch?
 

nsaspook

Joined Aug 27, 2009
13,307
In principle it's pretty easy. You need a switchable (high resistance and low capacitance when open) connection to a grounding plate that can shunt the circuit button sense energy to trigger a 'finger' detection.
1708454935019.png
Test clip connected to the 'ground' of the USB power cable to a typical phone.

https://www.youtube.com/shorts/tdOOKPsMTTE
 
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Thread Starter

Dimension

Joined Feb 20, 2024
2

nsaspook

Joined Aug 27, 2009
13,307
That sounds easy enough…I’ll give this a try. Thank you!
Just be careful of where the 'ground' wire/switch is connected (A DC charging or signal common for the touch-pad is better and safer than the utility safety ground on some random utility power socket) on the equipment and keep the wire short and the switching device (like a dry contact reed relay powered by a controller or remote circuit) small.
https://www.littelfuse.com/products/magnetic-sensors-and-reed-switches/reed-relays.aspx
https://www.littelfuse.com/media?re...lename=littelfuse-reed-relays-he700-datasheet

No promises it will work in your application.
 
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