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0
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2answers
98 views

Grid is capacitive in the evening

what does this term mean? "the grid in the evening is capacitive"? I work at a company and we are working on integrating a battery storage system on a utility scale for peak shaving of solar. When we ...
-1
votes
1answer
53 views

How to obtain the transfer function of the capacitive sensor?

I want to obtain the transfer function of this capacitive sensor which in the circuit, C is the variable capacitor that transforms displacement to electrical signal and E is the dc voltage source ...
1
vote
1answer
74 views

Convert capacitive touch sensing back to mechanical switches?

Capacitive sensing seems to replace often mechanical switches. Is there a way to convert them back to mechanical switches? Problem at hand is a cooking device with interfaces with the user via the ...
1
vote
1answer
39 views

How does capacitive EEG electrodes measures EEG signals

I have read the following sentences from an article: The effect that there are also charge displacements on the body surface due to brain activity is used for the capacitive measurement of the ...
1
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0answers
41 views

MPR121 low sensitivity problem

I bought the Adafruit MPR121 and connected it to a piece of metal which is covered by gaffer tape (no direct touch possible) talking to the MPR121 with the Adafruit library. The baseline/filtered ...
0
votes
1answer
44 views

Capacitive Moisture Sensor - Is AC or DC better/more accurate?

I am looking into making a capacitive moisture sensor. This has been discussed many times already, but I am not sure what is the better option, AC or DC. I want to run this off of a battery, so DC ...
1
vote
1answer
59 views

Which MCU (Atmel) I can use with QTouch library?

Some MCU have QTouch support - # touch channels implemented as a hardware. Is it true that QTouch library was designed only to work with such MCUs? Can I use it with, for example, 'old' ATmega48? Is ...
1
vote
2answers
51 views

Is there any material that obstructs or resists capacitive sensing?

For example, is there any material I can place over a capacitive sensor, or the finger or conductor approaching it, so that the sensor will no longer activate?
2
votes
4answers
222 views

Excessive temperature on cheap soldering iron - will series capacitor fix it?

Soldering iron came in a $14 USD kit off eBay. Lots of neat stuff, but the iron became so hot as to badly damage a DIY Kit. After a 2nd chance w/ the same results, it was hacked, Heating element of ...
0
votes
1answer
50 views

Trigger capacative button

My washing machine is equipped with a capacitive start button. A "button" is marked with paint on the plastic front and on the backside of the panel there is a spring extruding from the control PCB, ...
1
vote
1answer
46 views

What material can I lay over a capacitive touch screen that will still make it work?

So I am trying to build a capacitive touch screen in a table, but since the table is much larger then the touchscreen. I like to put something on top that not only make it easier to clean, but also ...
3
votes
0answers
65 views

Touchscreen Sniper [closed]

I was reading today about how capacitive touch works. This article on the Arduino site mentions that with a 40 Megaohm resistor you could detect an untouched "touch" from possibly 24 inches away. My ...
-1
votes
1answer
68 views

How to calculate inductive and capacitive reactance?

I am studying a project that calculate reactance power. I can measure apparent power, real power and power factor. Therefore I can calculate total reactance power. But I don't know whether it is ...
0
votes
0answers
39 views

EMI RFI housing / protection. capacitive touch

Can i create a effective capacitive touch(hover) button? Since the first day (playing with mcu's) i was impressed about the capacitive touch lib. The first time everything worked perfectly i wanted ...
0
votes
1answer
28 views

How can I interface to a capacitive sensor and measure its value with my Netduino?

I've just bought a rain detector, not realizing it is a capacitive sensor (I had assumed it was going to be resistive, as most are). However, being capacitive means it can be sealed so no electrodes ...
4
votes
3answers
215 views

Making conductive traces for capacitive touchscreens

This is a follow-up to this question I asked years ago. A short summary: I'm using a head pointer (see my linked question for a photo) with a tip made of plastic, thus non-conductive. The shaft is ...
1
vote
1answer
46 views

Capacitive Sensing and Dielectric Coupling

I have a design that uses the MPR121 capacitive sensor. It's a very simple board with 10 "slider electrodes". Standard 2 layer construction with FR4 .063" thick. The board interfaces with a ...
1
vote
1answer
78 views

Need help for calculation of this capacitive power supply

Look at this circuit. It's an almost complete capacitive power supply with necessary part. simulate this circuit – Schematic created using CircuitLab I have trouble calculating: the ...
0
votes
1answer
25 views

capacitive power suplply

i have following doubts about capacitive power supply or transformerless power supply... what will be real power drawn, will it be 230 x (current flowing through C1) or 6 x (current flowing through ...
1
vote
2answers
131 views

How to do capacitance measurement with high frequency oscillator

There are many types of capacitance sensors. I recently come across moisture sensors which measure the dielectric constants of the materials and correlate them to the water content level. It turns out ...
0
votes
0answers
145 views

Capacitive touch not working (AT42QT1011)

Trying to use AT42QT1011 for a touch (and if I am lucky - proximity sensor) as follows (from datasheet): The Cs is 10nF, Rs about 330 kOhm (also tried without). Vdd is 3V from batteries. SYNC/MODE ...
0
votes
1answer
104 views

What is the minimal capacitor (capitor type/size/capacity) needed to fool a capacitive touch screen? [duplicate]

Say I want to provide a device (completely batteryless of course, and detached from any human touch) the capability to immitate a touch on a capacitive screen (Galaxy S6 here). I know I just need some ...
6
votes
10answers
3k views

How to make 1 bit permanent memory circuit?

I would like to make a simple circuit to store or save 1 bit of data. The circuit should be able to remember the state of an LED ( on or off ) even if the supply is disconnected from the circuit. I ...
4
votes
0answers
116 views

What material can I lay over a capacitive touch screen to block its operation, while still allowing me to see it? [closed]

I own a Kindle Voyage and would like to be able to hold it anywhere, not just along the edges, while reading. So I'm looking for a material that's clear to read through, relatively lightweight, and ...
0
votes
1answer
197 views

Simple capacitive proximity/touch sensor problem

I've found one simple schematics for capacitive sensor on electronics-project-design.com, and implemented it as follows: The B? is 9v battery. Sorry for the odd-looking schematics: gschem usability ...
1
vote
1answer
266 views

capacitive sensor and wire length

I'm a newbie and I've been playing with the awesome Adafruit CAP1188 capacitive touch gizmo. As long as I keep the length of the wires from the CAP1188 to my copper sticky pads to a couple of feet, ...
0
votes
2answers
758 views

How do you measure soil moisture using a capacitive sensor?

There are a number of capacitive moisture sensor designs on the internet, which use the insulated copper pads on a PCB.For example: ...
0
votes
1answer
66 views

Capacitive sensing between two copper plates

Is it possible to detect touch event and its position coordinates between two copper plates spaced apart by approximately 6-7 centimeters? The space between plates have to be transparent.
0
votes
1answer
114 views

What sensors can accurately detect size of content in a closed container such as number of pills in a pill box?

I am a DIY enthusiast playing with different sensors and electronics. Recently I've been trying to make a pill box for my grandparents to track their medicine intake. However, I cannot determine ...
3
votes
2answers
112 views

Finding the touching angle on a touch-screen?

I am wondering if it is possible to detect from which direction (or at which angle) a human touches a touchscreen. Imagine something like this: Is there any technology out there (e.g. special ...
0
votes
1answer
87 views

Given the dynamic and static power consumption how does one determine the total power for the capacitive load?

I get that the capacitive load is determined which is also indicated by this question: $$\frac{Power}{Voltage^2 \times frequency} = Capacitive Load$$ However, I am not sure how power (which is ...
3
votes
1answer
94 views

capacitive touch screen

I am currently trying to build a capacitive touch screen. My end goal is to create a giant track pad/keyboard for my computer. Since abnormally large touch screens are quite pricy I have set out to ...
0
votes
1answer
47 views

Are capacitive display(s) capable of measuring what fraction of a finger is touched?

I'm really curious to get an answer for this question. Since I don't know the functioning of a capacitive display and Google didn't help me on this issue, I landed here. :) Are capacitive displays ...
0
votes
1answer
52 views

Feasibility- Flex Capacitive Touchpad

I'm a student(don't know much on Eagle) working on a project where I need a way of multi-touch finger tracking on flexible material. Will flex pcbs work?
0
votes
0answers
58 views

how to realize your op amp is driving capacitive load

I am new to the forum, hope everyone is doing well. As the title stated, I have read some app notes and some website about compensation a capacitive-load-driving and found there are some technique to ...
0
votes
1answer
195 views

QTouch Matrix ATmega8 issues

After trying a lot on QTouch Matrix for ATmega8,It didn't work for me. So sharing the trouble here. I have taken reference from this beautiful article. Here he had provided a schematic and PCB ...
1
vote
1answer
153 views

What are possible reasons for this not to work

I connected a 5V relay to an Arduino. It then opened and closed the relay, which had on a terminal (doesn't matter which one?) a wire that went to an iPhone' screen (with tin foil at the tip). On the ...
-1
votes
2answers
87 views

Capacitive ECG electrodes and capacitor discharge

I am trying to make ecg electrodes with capacitive coupling. Since my capacitor is only about 10 pF at max and I have to have as low cut-off frequncy as possible, I came up with a circuit like this. ...
4
votes
1answer
214 views

Inrush current limiter - design questions/review

I am considering to use the inrush current limiting circuit that was suggested in this answer. I have a pretty big capacitive load of about 40000uF to charge. Its a buffer for a GSM modem that needs ...
1
vote
1answer
331 views

Capacitor Touch switch with QTouch

I have been working on QTouch Implementation for ATmega32 Micro controller. I have taken reference from here. I'm facing issue with grounding Problem. For debugging process I am displaying the result ...
5
votes
1answer
165 views

Electric shock from laptop due to capacitive coupling?

If a person touches an exposed wire (the wire has a ground-prong) on the 20V side of a power cable while barefoot, I heard that it is possible to receive a shock of higher than 20V due to capacitive ...
2
votes
2answers
425 views

Causes of ringing in a PCB

Im trying to understand the source of ringing at the termination point of a PCB traces before i delve into actually designing a PCB. For example, by 'termination point', I mean a clock signal ...
0
votes
2answers
468 views

Insufficient ground supply on my circuit? Ground capacitive foil

I'm playing with a wireless sensor device (with atmega, xbee, and Capacitive sensor (simple foil)) that works fine with the lab power supply but as soon as I try it with AA batteries stops working. ...
0
votes
2answers
118 views

Capacitive touch directly above LEDs

I'm trying to make a design where the user can run his/her finger directly over a series of 10 LEDs (covered with 1 mm glass), and the LEDs should glow on/off based on the finger's position. I wish ...
0
votes
1answer
108 views

Calculating the voltage out of this particular cap coupled circuit

Before I get to my question, I'll just go over the input and output of the circuit from what I "know". The base of the BJT gets a 20 microsecond pulse that puts the bjt well into saturation and "VOUT" ...
2
votes
2answers
177 views

Is a capacitive touch screen safe to use?

I was reading about capacitive touch screens. I understood that your hand picks some current flowing on screen. That sounds alarming. Is it safe to use a capacitive touch screen, since it picks small ...
1
vote
1answer
159 views

Capacitive touch on off power switch

Is is possible to use capacitive touch as a power switch for an embedded project? Can a microcontroller turn itself off and somehow still monitor an input pin? Or is there a dedicated IC that can ...
2
votes
4answers
2k views

Given a load, how do you calculate whether it is capacitive or inductive?

If the impedance at the load has the form of \$Z = R + jX\$, where \$R\$ and \$X\$ are positive real numbers, then then network is called inductive. If \$Z = R - jX\$, then the network is called ...
1
vote
0answers
62 views

Capacitive where is the touch?

I am a newbie in the world of circuits and electronics. But we all started somewhere. I have this idea about a street sign that should be used as an instrument. All most like a Theremin. Touching it ...
0
votes
1answer
166 views

How can I make a POWER-LED Lamp?

What is the best way to light 10 POWER-LEDs with AC mains (220V)? (I want to make an LED lamp.) Here is more info: I have 10 of these POWER-LEDs: Product Chip: 40x40 mil Chip Brand: ...