Questions tagged [arduino]

Be sure to use the Arduino Stack Exchange for questions that are more Arduino and less electronics.

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70 views

What are these female 2.54mm (0.1") crimp terminals?

So I but some crimping terminals to make my own custom cable connections for the first time today for an Arduino project I'm currently working on. Comparing to some older ones I have from premade ...
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5answers
164 views

Electromagnetic 7-segment flip display: H-Bridge alternatives?

I have an electromagnetic 7-segment flip display which has 28 electromagnets for 4 digits. They run on 20V, have a 7.5W power rating and need alternate polarity applied to switch between the 'on' and ...
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1answer
125 views

How to increase current while keeping the voltage the same?

I currently have an Arduino Uno board which has an output of around 5V @ 900mA. Is it possible to bump up the current to around 3-4A while keeping the voltage the same? Maybe with a transistor, but I ...
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1answer
32 views

How to connect a Sparkfun LiPoly Charger to an Arduino Nano?

I was able to upload the Adafruit SSD 1306 OLED Library to an OLED Display using an Arduino Nano. Now I want to power the Arduino Nano via a Lipo Battery but the battery must be rechargeable and I ...
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0answers
37 views

Control motor direction with BTS7960

I am using the same BTS but I am controlling it with labview. I am able to control the speed in one direction, even though I have both R PWM and L PWM connected to PWM pins 3 and 7 respectively on my ...
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0answers
50 views

Why does my circuit short when powering through the same board as compared to an external power?

I have designed a board which follows this schematic: What I’m trying to achieve is using a N-Channel MOSFET to make the SDOOR inputs connected. The SDOOR inputs are from another controller (STM20) ...
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1answer
59 views

Potentiometer volume control for a piezo buzzer in bridge (2-pin) configuration

I have a 10K potentiometer that I'd like to use to control the volume of a piezo transducer/buzzer, which is driven by one or more MCU PWM-capable pins (ranging from 0 to 3.3V). Originally, my ...
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0answers
46 views

NODEMCU _ MCP23017 IO Port Expander Schematic Design

I am designing a relay driver using NodeMCU and need additional IO Ports, therefore I have designed a schematic utilizing MCP23017. I think the schematic looks good, however before I order PCB's ...
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3answers
122 views

Connect a Switchboard to Arduino

Sorry if this is a simple question, but I‘m quite new to Arduino. What I‘m looking for is a way to connect 100+ strain gauges to one Arduino board. Now, those each need a separate ADC (HX711) to ...
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1answer
63 views

What Is The Correct Way To Recombine A Split Serial Signal?

I am trying to replace the lamp and ballast assembly in an Acer P1500 DLP projector. The ballast is an OSRAM PT-VIP-05 COMPACT. It features a UART control scheme that allows the motherboard to query ...
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2answers
76 views

Wrong ground reference producing wrong output on ADS1115

I am currently working on a project, which involves measuring current in a DC circuit and storing that generated data on an arduino microcontroller. I decided to go with the ADS1115 and a shunt, which ...
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2answers
58 views

Arduino for detecting low voltage on UPS

Scraping together some parts, I managed to build a 22AH 12V battery pack, but I don't want to damage the batteries. I am using 4x 12V 5.5AH UPS batteries wired in parallel. I have an Arduino Uno, ...
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1answer
40 views

UART noise on audio lines

I have a fairly simple circuit with an Arduino and a SA818 RF module, I'm providing 3v3 power to the SA818 via two series diodes (dirty I know) and am communicating using software serial, of which the ...
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1answer
57 views

High Power LED Circuit Design & Constant Current Source Question/Feedback

I'm trying to design a dimmable LED circuit board. It's controlled by Arduino with its PWM signals. I'm new to electronics so I have some question regarding my design and knowledge on it. I've ...
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1answer
40 views

How do I read a simple touch sensor value from Arduino? [closed]

I suppose instead of connecting to the LED it will connect to A3 on the Arduino for example but I'm having a hard time making it work. I don't know which point on the circuit should be connected to ...
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1answer
77 views

A simple Arduino Uno HC-05 system doesn't work

I have an Arduino Uno, HC-05 module and an LED. I want to connect the HC-05 to my phone and with an app be able to turn on and off the LED and at the same time sending a message from the Arduino to ...
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0answers
72 views

What is the recommended way to connect TP4056 charger module to NodeMCU v2

I want to power a NodeMCU v2 with a 3.7v 2000 mAh LiPo battery and charge the battery with the NodeMCU connected (i.e. under load). After looking into various forums, I ordered a TP4056 battery ...
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0answers
21 views

ESP8266-12E & BPM180 - Bad pressure retrieved

I have NodeMCU (esp8266-12E module) and connected BMP-180. I try to read pressure from BMP-180 in async web request, but it reads bad value. For testing purposes I log pressure in loop() - and it's ...
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1answer
108 views

Door lock solenoid with finger print & Arduino Nano

Update - 22.01.2020 Here is my schematic. I tried to use all of the comments guys below: Should I use a fly-back diode as commented after I cleared the schematic? If yes, where? Is it required to ...
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1answer
41 views

Circuit design and power management in an Arduino project with stepper motors and solonoids

I am working on a design for a Arduino driven project that controls a 1.7A stepper motor and 2 small solenoid valves. I am using a 12v power supply (Meanwell MDR-60-12) to power the stepper motor (...
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1answer
75 views

Arduino current measurement

Hello I am planning to use an Arduino to make a joulemeter for a current range of 0-30 amps and voltage range of 0-24V. The voltage measurement is fine but I have questions about current measurement. ...
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1answer
136 views

2n2222 can not make it work as gate

simulate this circuit – Schematic created using CircuitLab I am trying to make a simple switch with the 2N2222, so i can send 5 volts from a 3.3 V output pin on an arduino/raspberry pi. I have ...
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0answers
59 views

NodeMCU-12E - Conflict between I2C and SPI

I have SPI SD-card module connected to nodeMCU, and it's worked well. Next I try to connect I2C sensor, and it doesn't work. Looks like SPI conflicts with I2C, because when I disconnect SD-card, I2C ...
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2answers
473 views

Purpose of a Pull-Down resistor [duplicate]

Being just a beginner I'm really getting confused of pull-down resistors. Please have a look at the diagram below. Here there is a 10k pull down resistor is connected to ground and the pin 2 of ...
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1answer
104 views

ESC signal standard and PWM frequency

I got the following code from the video. However, I encountered an issue that, the motor tended to stop working at maximum value. ...
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4answers
152 views

74HC595 8x16led matrix arduino

I'm currently trying to learn how multi shifting is working and have therefore started a project where I wanna drive 2X 8x8 LED matrix with an Arduino. I have found it that I should work with the ...
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0answers
94 views

Replacing an ammeter with voltmeter?

I have found this circuit of a millivoltmeter, and it seems like something which as a hobbyist I can do it, and the range of the measurement is very suiting one of my projects, but I would like to ...
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5answers
327 views

Infinite loop on microcontroller vs modern CPU

On a microcontroller (more specifically, on an Arduino Uno board using the ATmega 328P microcontroller) I would normally use an infinite loop to check for inputs etc (in Arduino land, this is normally ...
8
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4answers
3k views

How can I make my PNP amplifier circuit to turn off faster?

I'm using the following circuit to switch a 24V signal to a PLC. The rising edge is fast and perfect(38 ns) but the falling edge of the signal is not as good(3.5us)! How can I modify this circuit to ...
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1answer
98 views

AC Nanovoltmeter for Arduino alike?

I have searched across web, but I am unable to find such a circuit. I am looking for a circuit of a AC nano-voltmeter in range 5-10 to 100 nV which output is suitable to be handled by some precise ...
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2answers
161 views

Proper usage of PC817 Optocoupler

I'm creating a logic based circuit and below is my schematic. The circuit first steps down a 24 VDC input to about 3.7 VDC using a 150K ohm resistance and a 5.1V Zener diode. This 3.7 VDC is fed to ...
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5answers
150 views

Small 5V BLDC motor controller - 6 mosfet IC

I am creating follow focus system (motor with gears that moves camera lens ring). I think the best choice is BLDC motor (DC geared are too loud, stepper don't have enough torque or too big). I need ...
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0answers
76 views

0-5V Audio Signal with TL082

I am working on an Arduino project that requires me to be able to handle audio input from a 1/4" input jack, and it needs to be powered with just one 9V DC input. Since the Arduino cannot process ...
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1answer
33 views

Non-intrusive Detection of Power On/Off for a Piece of Instrument

I have a spectrometer that is basically a diffraction grating driven by a stepper motor. I am controlling it with an Arduino UNO that sends off a pulse train, each pulse moves the grating by some ...
2
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1answer
87 views

Trying to wire up a couple dozen LED-lit toggle switches to an Arduino Mega

Update: Worked out a rough (I'm sure) schematic of the current idea for a smaller version of the circuit. A bit of info before the question; The Arduino has a current cap of 200ma across all I/O pins,...
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2answers
38 views

3v output to switch on transistor for 5v fan

Im having trouble selecting resistors for my circuit. I have a 5v supply and my wemos board has a digital pin output of 3v. I want to use the wemos output pin to switch a transistor (BC547) on to ...
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2answers
141 views

How can I use an Arduino to simulate button presses on this Remote Control PCB

I read with interest here this post: How can I use an Arduino to simulate button presses on this PCB I am a beginner in this and I am trying to learn how to do this based on a small remote control I ...
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1answer
70 views

Voltage and Current Sensor for Alternating Current

I want to measure the voltage and current of a AC powered device using a micro controller like Arduino. I am unable to find it.(I am new to these). Is there a circuit or sensor which isolates from the ...
1
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1answer
67 views

Soldering iron thermocouple measurement HELP

I'm working on a relatively simple soldering iron circuit. I'm using a T12 tip, which consists of a resistor and thermocouple in series. I'm driving the gate of the N channel mosfet with 20V via a ...
16
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6answers
12k views

In this transistor circuit, what is the purpose of the diode across the motor?

I am trying to follow an Audrino tutorial with my kid and I am confused by the role of the diode in this circuit. In particular, I have the following questions: It looks like the circuit will work ...
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1answer
76 views

How to control a boost converter by using pwm from Arduino [closed]

I am creating a simple boost converter that step up voltage in the range 5V-30V. The switch is a MOSFET controlled by PWM output of an Arduino (with additional necessary components.) I want to ...
0
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1answer
38 views

How to use arduino control an ESC and flash?

Basically, I want to use PWM wave or something alike from Arduino to directly control the speed of a brushless motor through an ESC. I saw an example on the Arduino Brushless Motor Control Tutorial | ...
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0answers
67 views

Wireless Audio Transmission with NRF24L01

:) I have been planning to do a project on transmitting audio through arduino using NRF24L01 RF Modules at the same time sending data commands. I am really a beginner in terms of audio circuits so I ...
1
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1answer
108 views

How can I electronically generate a signal similar to the one produced by striking a piezo?

I feel like this is a bit of an unusual request so I'm having a hard time figuring out how to research it. My question is: is there some way that I can use an Arduino to programmatically generate a ...
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0answers
41 views

Amplifying analog signal from AO of KY-038

I'm using a KY-038 for sensing sound if I connect the DO pin and set the potentiometer to the highest viable sensitivity then if I make a loud sound it detects and sends an output upwards until 1023. ...
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1answer
94 views

Why do I have to put my transistor after of my component, instead of before?

I'm working on a very simple project, where I want to control a 24V LED with my arduino. Since the arduino can't output that voltage, I have a separate power source, and use a transistor. This allows ...
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0answers
54 views

Problem with SPI communication to TDC-GP30 Ultrasonic Flow converter

I'm working in TDC-GP30 an Ultrasonic Flow converter chip. Which can be directly hooked up with ultrasonic transducers to get digital output. But the problem is according to the datasheet the chip can ...
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0answers
99 views

Strange readings from external ADC

I am using external ADC MCP33121-10 via SPI interface. I need to isolate this ADC from main procesor (Arduino Mega), so I used optocouplers. The ADC worked fine without optocouplers but when I ...
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0answers
46 views

Relay module and Arduino Isolation; How to acheive?

I'm going to control a 3phase motor with an Arduino Pro mini and and a 1 Ch. relay module. In numerous articles it's been advised to separate Arduino and relay module's Vcc. For sure, the second ...
7
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1answer
209 views

Arduino thinks I pressed a switch when I touch anything

So I have found something very strange and confusing, When I touch anything even my desk my arduino thinks I connected to the input of any pin I pick. here is a video of what is happening it even ...

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