5
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Why does the air gap between the electrode and the overlay of a capacitive sensor have a negative impact on the touch performance?
The problem is that air gaps not only influence the base capacitance, they also influence the capacitance of the touch sensor when someone actually touches it.
The air gap essentially acts like ...
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Is this a reasonable way to get >50 capacitive touch sensors?
With that many active zones, you're going to want to think about matrix methods rather than completely individual electrodes. Here's a relevant application note from Freescale:
Designing Touch ...
- 178k
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What material to use for a capacitive sensor?
There's an Adafruit capacitive touch beginner tutorial here that explains that the larger the surface, the more sensitive your touch pad. If you take a piece blank copper PC board and solder a wire ...
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No touch points close to the edge of the screen
Your touchscreen will return a raw ADC value that is proportional to where on the screen you touch. The full scale range of the ADC value does not necessarily however correspond to the full width/...
- 70.7k
2
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Measure diameter of a ball with Arduino
You might also consider measuring diameter using a linear encoder, which would add precision and accuracy at the cost of...cost. Or you could even go about it like digital calipers do - a mechanism ...
- 207
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Mutual capacitance sensor behaviour
Your reasoning is correct, the capacitance increases if the conductor gets closer to the PCB. The system could be modeled as two capacitors in series, the fringing effects of current/field lines above ...
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2
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Effect of charger on laptop touchpad
This is relatively common issue. Best addressed with chargers that actually have a protective ground (third terminal) that connects to the ground of the wall socket. Then shielding and metal parts (...
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Suggestions on how to desensitize a touch button
You could attach a thin sheet of clear material over the top of the touch sensor.
That'll reduce the touch screen sensitivity, just like it does with a mobile phone or tablet screen.
Cut up a phone ...
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2
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Suggestions on how to desensitize a touch button
The "false alarm" problem you're having is probably caused by moisture and/or contaminants in the sensing panel. Yes, it's possible adding resistance in series could stop the false alarms ...
- 5,969
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How can I use a microcontroller to trigger an existing capacitive-touch pad?
Yes, you probably can keep the touch pads working as designed, while allowing an external microcontroller to trigger them.
You've already confirmed that you can trigger the pads from a microcontroller ...
- 5,969
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I want to trigger buttons on a touch sensitive control panel (not a touchscreen)
Once you figure out how to make the switch operate electrically, you can often synthesize that with Quad Analog switches or with R or C or just jumpers.
That assumes the analog voltages suitable with ...
- 148k
2
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Voltage triangulation across a copper plate for touch sensing
Indium-Tin-Oxide glass is resistive (hundreds of Ohms at least); this forms a voltage divider. That is what is detected - the difference in voltage between many points.
But a copper plate is < 0....
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How can I repair a damaged flat 4 pin cable?
These flat flexible plastic cables break easily, even after a single attempt to reinsert it. Though there are guides to repair them, such as at Instructables, old ones may be brittle and likely to ...
- 5,241
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How to setup a GT911 touch panel using Arduino? (I2C communication)
This is a independant observation on GT911 i2c address.
Its i2c address must be selected during reset phase, else it does not communicate with any of the 2 i2c addresses. I wished it responds to a ...
1
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What is a subtle way to disrupt or cause interference to a typical laptop touchpad?
Capacitive touch sensors are obviously sensitive to any conductors present nearby - those conductors form an external capacitor plate and at the same time shield the sensor. If you put a piece of ...
1
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What is a subtle way to disrupt or cause interference to a typical laptop touchpad?
I did some quick tests with my touchpad:
moving a 0.05 euros coin (flat on the touchpad) works well
moving a 0.5 euros coin (flat on the touchpad) works well
moving a 2€ coin (flat on the touchpag) ...
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Dielectric break down of stacked glass layers
The answer is "yes" and "yes".
However, by adding an extra layer of glass you are effectively adding another resistor in series and halving the voltage across each. But if one breaks down, so will ...
- 14.3k
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How can I make an object with curved surface touch sensitive with Arduino?
Single-sided capacitive touch sensing works most reliably when the device itself has a ground connection, or at least a path to ground through its power supply.
If your ball is going to be free-...
- 5,969
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Cap touch measurement using digital pin?
I am not promoting the product but just to give you a hint. I have been using touch controllers and this is one smallest and just enough for the need.
MBR3102 from Cypress
It needs no extra pins. No ...
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Cap touch measurement using digital pin?
You don't say which microcontroller but some manufacturers offer a software library for capacitive sensing. Essentially they perform measurement similar to Qtouch technology. Library or not, yes this ...
- 172k
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Accepted
What shape do the electrodes of a touchscreen have?
For phone touch sensing screens the actual shape varies - I have designed them and we would do multiple simulations and subsequent testing of the design to optimize the position sensing linearity.
For ...
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What shape do the electrodes of a touchscreen have?
The ones that I've seen generally use a pattern of diamond-shaped electrodes, like here: An Analysis of Electrode Patterns in Capacitive Touch Screen Panels. I once saw a design for a wall-sized ...
- 178k
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vote
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How to sense touch on a diffusing sheet?
put something transparent and conductive in front, (or just behind the front layer).
Indium tin oxide is what they use to make touchscreens, but fine metal mesh would probably work almost as well.
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How can I build a touchpad/trackpad?
There are tons of external touchpads on the market, from the giants like Wacom, Logitech or Lenovo to cheap no-name ones. I doubt you'd be able to approach their precision in home-made device. Some of ...
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capacitive touch buttons through VERY thick glass or macrolon?
15cm means that whatever capacitance your potential finger-dielectric-conductor plane plate capacitor has will be extremely small, and so will be the difference between there being a finger or not.
...
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Microchip MTCH6102 - 2 touch surfaces (3x3) on one chip
Posting answer from Microchip forum, if anyone would stumble upon this topic:
MTCH6102 only handles one surface, so you will need two MTCH6102 for two touch surfaces.
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Large Rectangular Touch Sensor
Or do number 4. Definitely the cheapest and simplest one. Make use of the resistance of your body. The average human got about 5MΩ resistance in their skin. Passing through a small current is ...
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The accuracy of Force Sensitive Resistors (FSRs)
simulate this circuit – Schematic created using CircuitLab
300mV deflection at 2/3 FSR rating for load from 2/3 to 1 x FSR rating ?
Static load is probably quasi static, so dynamic touch will ...
- 148k
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vote
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Capacitor acting as a resistor
You probably won't be able to measure the change in capacitance between the strips being pressed together and not being pressed together, as it will be small, but it's still there. (I would guess that ...
- 8,297
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Measure diameter of a ball with Arduino
that's a nice question!
I've got an Idea, which might help.
You can use an ultrasonic sensor, and place them in front of a board, based on how large you want it to be. Measure the distance between ...
Only top scored, non community-wiki answers of a minimum length are eligible