Questions tagged [arduino]

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1answer
22 views

How to build synchronous boost converter with IR2104 mosfet driver?

Does anyone know how to build a synchronous boost converter with IR2104 mosfet driver? I am a beginner and I have noooo ideaaa how to connect the circuit. The placement of inductor and capacitor ...
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1answer
27 views

Why are Global Struct Variables not visible in Loop and in Function?

I created variables in a struct above void setup() so they would be Global. Prior to this the code ran. In Loop and in the one function I get error the variables were not declared in this scope. ...
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3answers
4k views

What is this symbol on the Arduino Uno Schematic

These look like capacitors, but they're not labeled and I'm not quite sure what to make of them.
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1answer
29 views

BJT Constant Current LED Driver - Inverted behavior?

I'm trying to use build a constant current Led driver, using two BJTs (BC338 and BC547). The idea is to be controlled by Arduino's PWM, for dimming. I'm using the circuit bellow. The led is a white ...
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1answer
51 views

I want to use the following command (PINC & B00000011) to read 6 different conditions from hall effect sensors

I need help with this code. I don't understand why it doesn't execute all 6 conditions. I am using PINC which is PORTC (A0-A5) on the Arduino Uno to read in 3 hall effect sensors from a BLDC at the ...
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0answers
35 views

Read triangular wave with positive and negative part to Arduino

I generate a triangular wave with a 555, and I want the Arduino to read this signal. What should I do to read negative part?
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4answers
530 views

How to detect distilled water?

I'm trying to create a circuit that detects water, however, I'm looking for a very accurate circuit that can even detect distilled water. My current circuit uses an Arduino that has a pin constantly ...
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0answers
57 views

Why did my motor drivers burst into flames when I disconnected them?

I have set up an old mobility scooter to be remote controlled with some cobbled together boards from the usual sources. Everything was working well for weeks until one day when I was trying to bind a ...
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0answers
65 views

BC457 transistor shuts down entire power on high signal

simulate this circuit – Schematic created using CircuitLab I'm making a microcontroller circuit to control a heater using an ATmega328, a 5 V relay, a 16x2 LCD display, a transistor etc. Now ...
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0answers
44 views

Digispark - Bootloader stuck

I have a digispark that I want to reprogram, soldered into a circuit. I have burned the default t85 micronucleus firmware. This is the command I used: ...
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1answer
63 views

PNP led on when it should be off

I am using a CTHSCIC06 capacitive touch button and have connected as per the datasheet (the motor side of the circuit is not needed) however I am still having trouble around the pnp side of the ...
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1answer
38 views

Design check for a high-side switch circuit, for driving Nixie tubes

I am designing a circuit that enables using an Arduino board to drive Nixie tubes (https://en.wikipedia.org/wiki/Nixie_tube), which are LED-like devices that require ~170V to ignite, and ~140V to ...
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0answers
14 views

Advice on powering a fan in a A1200, battery timeout auto poweroff question

I need to wire up a 3-5v mini fan inside an Amiga 1200 computer to attach to the graphics chip. I am currently connecting the fan to the 3.3v output of an arduino, and have the lid off my A1200 and a ...
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1answer
40 views

ATMEGA328 USBasp schematic

I have some problems about programming my ATMEGA328 with USBasp programmer. I have found different schematics for the connections and I do not know which I have to use (and I'm afraid to break ...
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0answers
27 views

Please help me out choosing the correct battery and designing the circuit [closed]

I'm designing a water vending machine for a specific amount of water please help me out to choose the correct battery and designing the circuit. The components I'm using are listed below I have a ...
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1answer
102 views

Help with servo and circuit board

So I've got a couple servos that I would like to hook up to an Arduino Uno. I'm not sure where to start. See album for more pictures. https://imgur.com/a/4pyYbzQ The questions I have: I can't find ...
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2answers
210 views

Can we use pir sensor while it's moving?

I fixed the pir sensor on the top of servo motor.while the servo motor's rotation the pir was also rotated by servo motor's motion.but the problem I had founded that pir sensor had always indicated ...
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0answers
24 views

Arduino w 5V Relay Wiring

I am having trouble actuating this relay I bought off Amazon. I have been successful actuating the relay but am having issues wiring up a LED to simply turn on and off. My setup looks very similar to ...
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1answer
43 views

Interrupts are firing when touching ground with metallic things

I'm making a circuit on a breadboard (before SMD design) for a battery-powered device. When USB is connected to any wall-adapter, the device wakes up when touching any ground wire on the breadboard ...
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2answers
28 views

Solid state relay is not completely open when control inputs are not connected

I am trying to control a 12W light using this solid state relay. Even when I haven't connected my control inputs through an Arduino the output light glows(very dim). I have an input voltage of 230V. ...
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3answers
84 views

Levelshift distorts when freq is higher than 4kHz

I 'designed' this circuit to shift a level coming from an arduino to -5/+5v signal. It simulates well in EASYEDA. I also built it on a breadboard with a symmetrical powersupply and signalgen giving ...
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0answers
48 views

Interrupt not affecting while loop

I have this little problem. I'm moving a stepper motor in one direction, and it should stop when it hits thevend switch located at the end of railing. I hooked that switch to interrupt 2 on an Arduino ...
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1answer
34 views

Is it possible to use i2c accelerator to multiplexer input?

I have 10ft long wire cabled i2c 4 buses (for 8 sensors, sensor are not in the same place each has 2 i2c addresses), I try to use i2c multiplexer PCA9548A with an i2c accelerator Ltc4311, i2c ...
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1answer
26 views

How to handle low voltage stepper motors?

So I've been looking at various NEMA-17 stepper motors, and I noticed that a most have an extremely low voltage. For example, on this page, there are NEMA-17 motors ranging from 2.8V to 5.4V, with ...
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1answer
71 views

What is the simplest EEG detecting circuit possible? [closed]

Suppose I took an Arduino and hooked it up to two electrodes: one to the front part of my head going into A0 and another connecting my earlobe to ground, why wouldn't this system be capable of ...
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0answers
26 views

OV7670 camera, how to use external SPI SRAM?

I'm using OV7670 camera with no FIFO and Arduino Mega2560 and I want to send 76800 bytes to my laptop, because of Arduino RAM limitations, I'm planning to use Serial SRAM 23LC1024 (1Mbit) so I can ...
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3answers
104 views

Where do I code for the Arduino? How do I decipher the code? I am quite lost for Arduino [closed]

How do I make use of the code? Where do I code it?
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0answers
37 views

SAMD21G18 not working at 1.8V

I am working with a SAMD21G18 and a custom board based on Sparkfun design and I am using VSC + PlatformIO. Actually I want to run at 1.8V instead of 3.3V. Now, the hardware works well at 3.3V but ...
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2answers
106 views

I²C Slave Reset routine

UPDATE: Code snippet already done below. Not sure if correct. I implemented the routine which is found in Microchip's datasheet in order to reset the EEPROM memory (24LC512)in case it hangs up. But ...
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1answer
51 views

Serial Communication between two Arduino not working

I'm trying to perform a simple communication sending two strings in two char arrays from an Arduino Uno to another one. My problem is that after the 5th or 6th iteration the two strings will mix. ...
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1answer
31 views

relay voltage drop

I made a simple ultrasonic project with Arduino. Used an LCD to show the distance. Also I want to turn a LED on with a 5V relay with a switch for some reason. I'm using external power supply 7.5V 2A ...
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0answers
41 views

Controlling a mechanical doorbell with an Arduino UNO

I'm trying to control a mechanical doorbell (a small white box with two chimes) using an Arduino UNO. The UNO uses a relay (a 5V relay module something like this) to switch a 12V power supply attached ...
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0answers
50 views

How to detect unknown circuit button press without interfering with circuit

I have a membrane keypad in my dental chair where part of the it’s logic system is burned. So one of the buttons I need, that turns on and off a head lamp, doesn't work anymore. So with an arduino I ...
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0answers
24 views

ESC motor calibrated, but still beeping and not responding

I am using this motor called abcGoodefg RC 2200Kv brushless motor. At first, when we followed the sample code on this website, things went well. But when we changed 1000 and 2000 to 10 and 20, ...
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4answers
3k views

Stepper motor won't turn, just vibrates

I'm using 2 x 1.8-Degree Nema 14, 35 BYGHW Stepper Motors with a DRV8825 Stepper Motor. I have tried all 24 combinations of wiring the damn 4 wires but it won't work. I am using a 9v battery as the ...
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0answers
54 views

Why IBT_2 motor driver is more powerfull with Arduino then with Stm32

The question is why in DIY Force Feedback applications for PC racing simulators, the FFB is more powerfull with Arduino then with STM32. Can it be due to the diffrent logic level that goes from them. ...
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0answers
37 views

Load cell behaving weirdly. Output magnitude of force depends on which side is held and which side force is applied

also asked at: https://forum.arduino.cc/index.php?topic=670246.0 I have a generic load cell (image) and am using Hx711 which is connected to arduino. The code is from Instructables. When I fix and ...
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0answers
24 views

Modifying smart watch or activity armband with further sensors

I want something like an activity armband where I would like to add an bend sensor or EMG sensor for simple hand gesture recognition tasks. I could probably build it from scratch with arduino-like ...
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1answer
39 views

How to measure a signal that uses a virtual ground using Arduino

I've created an EEG system that measures the potential difference between: 1) The differential amplification between EEG voltages. 2) a virtual ground between two 9V batteries. I'm trying to measure ...
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0answers
27 views

Feedback on USB-C Power + LiPo Battery + Nema 17 Stepper Motor PCB Design

TL;DR: I need a technical check on my circuit design that utilizes LiPo battery & USB-C charging. Hi everyone, I've been working on a project to build my own camera slider. It's powered by ...
6
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8answers
7k views

Why does a bipolar transistor not work, but a MOSFET does

In reference to my question Arduino Controlled Power Supply for more details and a test program. Why is it that my circuit involving a transistor does not work (see below) whereas a similar circuit ...
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1answer
141 views

Arduino controlled power supply

I have built the circuit as shown below. The goal is to power the Arduino by battery and maximise battery life by turning off power when it is not in use. There is no need for the Arduino to wake up ...
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3answers
57 views

Driving RGB Leds from ESP8266

I want to create a schematic for the following behaviour: I want an ESP-12e (ESP8266) microcontroller similar to an arduino, to be able to control 10 RGB leds , changing their colours from blue to ...
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1answer
61 views

Which stepper motor should be enough to move a water valve and for the TMC2130 driver?

I need a stepper motor and a driver to control it. But I don't know which would meet my needs. I have an Arduino MEGA 2560 if that's relevant. Aim I need to close and open a Nupro valve with ...
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2answers
71 views

Single Resistor on Common Cathode Display Is Not Limiting Current (With 1 segment lit)

Today I did a little test and hooked up my arduino nano to a seven segment common cathode display. I attached a single 1k resistor to the cathode pin of the display, and then lit a single segment ...
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1answer
61 views

How to control motors with an arduino

I am a complete beginner with electronics mostly dabbling as a hobby so please forgive me if I struggle to follow or don't understand specific terms. I have been working on a project for a while now ...
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1answer
53 views

230V switch controlled by Arduino Uno (Atmega 328)

I need to realize a switch for an electric motor whose power supply is at 230V. That switch must be controlled by Arduino with a certain square wave signal. If the voltage was lower, I'd build a ...
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1answer
64 views

Can I use the 1.8 inch TFT LCD SD slot for other purposes other than displaying images on the display?

Can I use the 1.8 inch TFT LCD SD slot for other purposes other than displaying images on the display? For example, storing text files on that SD card (that's on the display's SD slot)? Can I use that ...
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1answer
44 views

Adafruit SSD1306 Scrolling Function

So, there is a function in the Adafruit SSD1306 Library that prints a scrolling text. For examples, display.startscrollright(0x00,0x0F); will print a text scrolling towards the right. What are the ...
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1answer
52 views

Random Values Gained From Sound Sensor

simulate this circuit – Schematic created using CircuitLab I am currently trying to test my sound sensor, before I hook it up to a bigger project. I have changed the code from digital to ...

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