Sorry if this is in the wrong section.
Hi All,
I am after some help with the AT42QT-1011 capacitive touch sensor. A little history before I ask my question.
full history here: https://forum.arduino.cc/t/proximity-se … /970815/16
TLDR: I have 24 sensor points that I want to trigger through about 1 cm of wood. The ttp-223 break outs I used with a ring of copper wire soldered to the sensor pad would trigger about 0.5cm above the wood, however due to the ‘auto-calibration’ ‘feature’ they stop triggering after 7-8 seconds. The AT42QT-1011 datasheet says this sensor will stay ‘triggered’ for as long as it senses something. I have bought a few to test.
My questions are:
1: touching the sensing pad on the AT42QT-1011 with my finger has mixed results. Some times it will stay triggered for as long as my finger is touching and some times it will only last about 6-15 seconds before the led switches off. I did read some thing about power maybe being the cause of this. I have tried it using a breadboard powered from a 5v adapter and from a USB connected to a PC and the results are the same. The item I’m trying to build is powered by this: https://www.amazon.co.uk/Switching-Powe … B07Q2WQ8DS So what could be the issue here and for the final item is there a recommend PSU?
2: I am experimenting with adding an external sensing pad so it will be triggered through the wood, again with mixed results. I have some copper tape and this kind of works through the wood but some times not and then doesn’t stay triggered. Any ideas on how to build a pad that works through the wood would be gratefully received.
Thank you for your help.
Adam
It’s quite unusual that the code given in the hookup guide is not giving the proper result. I think you will get a better result if you try to read the sensor with an interrupt pin. If still it does not, I think you’d better claim a replacement.
Hi,
Thank you for the reply and your patience with my slow response.
I will try the interrupt method. However I’m not sure this will work any better, as using an external sensor I can trigger the AT42QT-1011 through about .5cm of wood no issue, it just stops being triggered after anywhere between 8 to 60 seconds, it’s not consistent. I have tried various ones from various batches I’ve ordered and the same effect. This is better than the ttp-223’s as they all stopped after 7 seconds, (a design quirk), but I did hope these would stay triggered.
TS-John, anyone from sparkfun.
I have tried using the interrupt method with the at42qt-1011 board I have from yourselves (bought through digi-key). from the notes on the product page, I have also made sure that there is a proper 5v supply to the break out board using usb from a computer, a power adapter from my electronics kit and a industrial 5v led power supply, and all have the same result. Of the 25 at42qt-1011 board i have, none of them stay ‘triggered’, unless I hold the on board touch pad tightly for more that 40 seconds. even touching the on board touch pad often only stays triggered for 10-20 seconds. I’ve connected various external pads from sheets of copper tape to rings of various thickness copper wire and non make a significant difference to the triggered time. Am I missing something. Do I need to create a specific external pad, can I turn up the sensitivity so it stays triggered. This is not working as advertised and I need some help please.