Hello all! I hope everyone is staying safe out there from the virus.
This is a weird question, but are Nextion, for example, resistive and capacitive touch displays isolated? I want to use an arduino, ads1115, voltage divider, to measure a HV battery pack (150VDC), and then display voltage on the display with a cool graphic. I know I need to power the arduino with an isolated DC/DC converter so the HV isn't connected to GND of the chassis (this is in a car).
But I am just not sure with how the displays work, if I will get shocked when touching the display or something. I want to use the differential measuring part of the ADS1115 as well.
Any feedback on this would be greatly appreciated, I just am unsure how or if this issue would in fact be an issue. Maybe I am just overthinking with safety in mind...
Thanks!
I think the answer is yes, but that doesn't help you.
The Nextion capacitive panels have a piece of glass on the front so are very definitely isolated to some high voltage. The Nextion resistive panels are, I think, some kind of thin plastic layer that will probably isolate you but I certainly would not trust my life to it.
However, there are 2 things wrong with what you are asking:
First, the display should not be the point of isolation. You should build some electronics that work safely with the high voltage and sends the data out through some kind of isolator to some properly grounded, and safe, electronics that communicates with the display. For example, I have a mains voltage and frequency monitor that is directly connected to the mains. It is in an earthed metal box and the output is via 2 opto-isolators. It is powered through an isolated DC-DC converter with a rated isolation of 1500V.
Second, if you really, really need a display that's safe under the conditions you describe then you ask a display manufacturer for one, not some folk on an internet forum who might or might not have your wellbeing at heart.
I'm afraid I have to invoke my usual warning to questions like this: If you have to ask then you don't know enough to do this safely, pick another project.
The display should communicate only with equipment that is operated at safe voltage levels (e.g. 5V). Then there is no issue.
Completely isolate the high voltage equipment from the display components using optoisolators.
A schematic (not a pretty Fritzing picture, please), would generate more specific guidance.