Hi all, I am watching some amateur projects about the capacitive sensors.
Cool but I notice all examples using copper.
Can I use same logic using aluminium stripes instead copper?
If yes, what change in the resistor choose?
The CapacitiveSensor library Playground page talks exclusively about using aluminum foil:
http://playground.arduino.cc/Main/CapacitiveSensor
From this Hackaday article, I gather that soldering to aluminum is difficult, which I would assume is why the much more expensive and less readily available copper is used:
A video is provided in the comment thread of that article which shows how to solder to aluminum foil:
I would guess that no change in resistor value is needed for aluminum vs copper.
pert:
The CapacitiveSensor library Playground page talks exclusively about using aluminum foil:
Arduino Playground - HomePageFrom this Hackaday article, I gather that soldering to aluminum is difficult, which I would assume is why the much more expensive and less readily available copper is used:
Conjuring Capacitive Touch Sensors From Paper And Aluminum Foil | HackadayA video is provided in the comment thread of that article which shows how to solder to aluminum foil:
https://www.youtube.com/watch?v=_mYkM9lHMhoI would guess that no change in resistor value is needed for aluminum vs copper.
Thank you so mutch!
Just a question
can I use 10k ohm resistor instead 1M ohm?
Risk some damage or just value issues?
I'm glad if the information was helpful.
You won't have any chance of damaging your Arduino from using a 10K Ohm resistor but I suspect going an order of magnitude below the minimum recommended resistor value will result in a sensitivity that's not useful. It's worth a try though. If the highest value resistors you have on hand are 10K you can connect them in series until you reach a high enough resistance.
ahh very interesting.
One coulpe questions again!(promise)
A) If the aluminium sensor is covered with a thin plastic film so can it "feel" the contact?
B) If the aluminium sensor is touched by a rock? or a iron surface.. what will happen?
Thank you again!
It's actually recommended to insulate the capacitive sensor plate. The reason is to protect the Arduino from static discharge that might occur from someone touching the sensor who has a static charge. A thin plastic film should have not effect on the sensor. It's detecting the proximity to a human rather than the contact.
Regarding rocks and iron, I think it's best just to do some experiments. You need to understand the way this works. The aluminum foil is one plate of a capacitor. The other plate is the item being sensed. The space between is the dielectric. The Playground page has this diagram:
In this case the object is a human. It doesn't necessarily need to be a human serving that plate but there does need to be a difference in potential between the two plates.
pert, again and again thank you for all these precious info! 