# All Questions

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### Tool for using with CH341A based USB to I2C/SPI/UART/etc adapter

I've got this USB to different protocols adapter but now I need a software tool to interface with devices through this adapter from Windows. For UART it should provide a virtual COM port that I can ...
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### Will HD44780 display be hurt with 20mA on contrast pin? (pin 3)

I'm driving an LCD HD44780 display using my Raspberry Pi B+. Using a GPIO pin I'm managing the contrast adjustment (pin n. 3) on my LCD display with PWM. In the ...
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### How to connect a 4D display to a beaglebone

I am fairly new to all this so sorry if this question is rather trivial. I have a 4D Picasso Display (28PTU-Pi) and I want to connect it to my Beaglebone board. So plugged the usb cable into the ...
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### Will enclosing a brushed DC motor significantly reduce it's lifetime?

I designed a 3D printable LEGO-compatible enclosure for an inexpensive brushed DC motor. The intended use is outdoor holiday decoration, so I fully enclosed the motor to weatherproof it. LEGO ...
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### DHT11 & PCB problem

I made a board which includes 220V to 5V-600mA converter(I bought as a module), DHT11 and an atmega328p. I made a measurement on breadboard and I get 45% humidity and 24 C degrees. But when I get ...
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### Amplifing guitar signal in order to connect it to ADC

I would like to connect an electric guitar to ADC (or MCU internal ADC input) in order to process signal digitally. I'm not sure right now which MCU or ADC I'm going to use, nevertheless I believe ...
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### How do compact AM radios establish a ground?

I am trying to construct a radio and, at the first stage, I have finally detected circuit a signal. My previous attempts have failed and I have discovered that it is because it was not properly ...
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### How to measure the torque (of a stepper motor) with a (belt) drive accurately?

I have a project that requires really accurate torque measurement of a motor or a motor + a belt drive. How do I do that? I am guessing that measuring current through a stepper motor is is ...
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### What kind of relay do I need?

I have some remotely controlled sockets and I would like to rip open the remote control (3v DC) and connect it to the rooms lighting switch (240V AC) so the sockets are triggered when the light is ...
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### My “flash VS RAM” speed test doesn't work. Why?

In trying to demonstrate that copying information from a string in flash memory to RAM takes longer than copying from the same information in an array in RAM to another, I ran the following code on ...
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### Schematic is not working?

I have a schematic that I turned into a PCB, but to my dismay, it is not working and I can't figure out why. Here is my schematic : I have tested the board with a multimeter (3.275v and about ...
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### Get distance covered by a wheel using a gyroscope placed on it

I have to calculate the distance covered by a wheelchiar using data gathered from a gyroscope that was placed on one of the driving wheels. I know the total leght of the corridor we used for thye ...
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### A Hard Problem: Controlling TWO Lamps with ONE SPST switch (AC)

This is the text of the problem: Draw a circuit with Two lamps & one SPST switch. The lamps must be in opposite states.
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### Difference between Zero speed and Near zero speed geartooth sensor

I would like to ask what is practical difference between geartooth speed sensor which is able to detect zero speed and near zero speed movements. What is zero speed in this case? Thanx
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### If my electronics are outdoors in a ventillated NEMA 4 enclosure, should I conformal coat my circuit boards?

I'm considering putting a circuit board in a ventilated NEMA 4 enclosure outdoors. I'm a little concerned about humidity and condensation inside the enclosure. Do I need to conformal coat my circuit ...
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### Disable ATX low voltage protection

Trying to make adjustable PSU out of ATX like this one http://electro-tech.narod.ru/schematics/power/comp/codegen_cg-07a.gif by removing R76 and R33 and replacing R34 with pot. At first was not able ...
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### Determining Resistor for Heating Element

I am attempting to run a Molybdenum heat coil. The best I can tell it is 0.3-0.4 ohms per rack and I would like to run say two racks at 230V at 3.9KW (so it doesn't trip my 230V 20 amp breaker). Does ...
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### Power effeciency of Zener diode regulator

How to calculate the power efficiency of zener diode regulator? Is it correct to calculate it as the ratio of power delivered to load to the total power drawn from input source? If I am correct, ...
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### NAK in CAN when programming stm32f407vg uC

I am getting NAK error in CAN communication. Not really sure why, also frame itself is quite strange as in program I am sending different things. I have got two devices and therefore I monitor 4 ...
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### Reading battery voltage via frequency

I'm working on a project that involves reading battery voltage via a headphone/microphone jack. The batteries will vary between 3.0 - 3.6V. I'd like to convert that voltage to a frequency (linearly ...
24 views

### Find the right motor to lift a robot's arm

I'm trying to find the right DC motor to lift a robot's arm. I know the total weight of the arm, its length, and its center of mass. The motor only needs to lift the arm up about 45deg. How exactly I ...
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### Powering a WS2812B strip

After always being interested in learning more about electronics, I figured LED-strips would be a great start. I'd like to power a 4 meter WS2812B-LED-strip (60 LEDs/m). These run on ...
19 views

### Using Breadboard Power Rails for i2c Bus

I'm working on a raspberry pi project that will use about a dozen i2c devices (mostly mcp23017s) and the wiring is getting a little crazy. Are there any downsides to routing SDA and SDL to one of the ...
19 views

### Power loss through a medium

Say I amt transmitting an RF signal from an antenna through a non-freespace medium (e.g. sand, water, cement) how can I go about calculating the absorption losses up to a certain depth level? I feel ...
24 views

### Operational Amplificator Association effect on Slew Rate

I am designing a circuit which means getting sinusoidal signal as as Input and pass it to an ADC. Since the ADC supports tensions from 0V to 5V and my input 5Vpp, then I need to escalate it properly ...
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### Minimal, unity-gain filter design to remove high-frequency power-supply noise?

I have a 120-channel device which carries voltage signals at approximately 1MHz. However, my power supply is introducing a 30MHz noise component into each of the 120 channels. What would be a good ...
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### Understanding the summing-point constraint

I can't find any source online which explains this in a different way from the others. I'd like to think I'm not just being slow, but it seems that I might be just that, regarding the op-amplifier. ...
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### Antenna gps neo 6m

I am designing a pcb which has the module ublox neo 6m, instead of using the normal antenna I was looking to use a ceramic which should work with ublox. I have got this: ...
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### UART frame inversion

I have a problem when I send some character from an hyperterminal through an uart frame, I receive the wrong character. I use a PIC 18F46K80. In some test I did, I got these results : Test 1 : ...
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### Driving a small DC motor from MCU very slowly

I have a very small DC motor (like the one used in walkmans ages ago). I'm feeding a PWM signal of about 30KHz into the gate of a BS170 MOSFET which is shunted to ground via 15k resistor. The motor is ...
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### Effect of rectifier input frequency on output voltage

Does changing the input frequency of a transformer rectifier change the output voltage, given that the input voltage is constant with no voltage regulator or protection circuit on the output?
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### Can calibration improve the accuracy of a circuit?

If I have some resistors and a fixed-gain current shunt amp, that all claim "1%" accuracy can I make a system that's better than 1% accurate, if I put a calibration tuning pot into it, and adjust it ...
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### How this capacitor discharged by leakage of the diode in peak detector circuit…?

The text says: "When Vin is high the diode is FB and capacitor charges up to peak. When Vin is low the diode is RB and the capacitor tends to discharge. The reason given for this is the diode leakage ...
56 views

### Blinking 3 led's in parallel?

I have a PIC development board which has few on board led's. I am programming MCU so that it can blink 3 led's in a parallel manner. I have made the following code: ...
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### How to scan and differentiate multiple switches through a single input/output pin?

I was reading through the document tips and tricks using 8 bit controllers by microchip and found this diagram.I have seen this in application in some electronic circuits over internet but never found ...
32 views

### How to detect an object from the same color background with a camera? [on hold]

I am planning to use a CMOS camera and I would like to be able to detect objects that are moving towards to camera. Using some image processing, it seems possible to do this easily for large and ...
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### Getting resonant frequency in LC circuit with L as air core coil

im trying to find inductance of the air core coil,i read that in LC parallel circuit with known capacitor value we can find unknown inductance value by the formula so need to find 'f' resonant ...