Questions tagged [voltage-level]

Voltage level should be used for questions that are referring to using hardware together that operates on different voltages (the "concentration" of electricity).

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Arduino ESP8266 communication

I saw two peculiar things while googling this subjects. Sometimes Tx and Rx are connected directly despite the fact, that it works on different voltages, sometimes resistor dividor is used, sometimes ...
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30 views

Attiny ADC at voltages less than 5v

So, this is peculiar. I am using an ATTINY84 chip as an i2c ADC converter (there are reasons why I'm using this rather than a dedicated chip, but that's not really relevant), and I've noticed that I ...
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61 views

Output 3.3V when setting pin to high

I would like to pass 3.3V and Ground to an component. How can I achieve such a thing? I for example would like to let a wire get 3.3V when I for example do digitalWrite(pin, HIGH). It is hard for me ...
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182 views

How does the dual 5V and 3.3V output on the Uno R3 work exactly?

I'm constructing a circuit that needs both voltage supplies (for 3.3V RFID and 5V relay, GPS and screen) but the Uno is physically too big so I need to use a nano or mini pro, both of which I can only ...
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1answer
40 views

Can I solder wall cord directly to servo?

I have a servo which requires 7.4v and a wall power cord which says the output is 7.4v but the connector does not fit that of the servo. Is it safe to snip off the end of the wall cord and solder the ...
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32 views

Some noob questions regarding Arduino Nano based drones [closed]

Foreword: I am doing my Bachelors in Aerospace Engineering and part of the requirements to graduate (and get a good grade) is that I must complete 3 projects of my choice, and it must be unique. So in ...
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1answer
115 views

NodeMCU with HC-SR04 ultrasonic sensor

How can I interface an ultrasonic sensor with a MCU with 3.3 V GPIO like the NodeMCU? I tried powering the sensor with both 5 V and 3.3 V from the MCU. Both failed to show any results as the distance ...
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21 views

Voltage to keep my board safe

I have recently made a home automation system using node mcu and relay module and i am powering both together using my 5V ,2A dc adapter and i am scared that if I'll keep using it for very long hours ...
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1answer
154 views

Digital I/O threshold voltages for ATmega32u4

What are the voltages on a ATmega32u4 (eg Arduino Leonardo) such that a HIGH or LOW is read? I want to ensure that I'm reading the chip reference manual correctly, where Table 29-1 says: VIL: Input ...
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1answer
678 views

MKR WIFI 1010 Providing 3.3V to breadboard

The Arduino MKR WIFI 1010 product page says "The microcontroller on the MKR WIFI 1010 runs at 3.3V, which means that you must never apply more than 3.3V to its Digital and Analog pins. Care must be ...
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1answer
73 views

Arduino Analog pins go all to high problem

I was taking measures from the outputs of an OpAmp when all the sudden measure 5 volts from all pins of the Arduino Mega for no reason. I disconnected the Arduino and loaded the Firmata and test. All ...
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39 views

Checking Arduino 5/3.3V under load

Is there a way to use common/cheap components to put the 3.3V and 5V pins on an Arduino under load, in order to measure if they are giving a correct and stable voltage? Can I calculate a certain load ...
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244 views

5V MCP2515 to 3.3V Teensy. How to reduce the MISO voltage

So to try and speed up my project, I have moved from using two UNO's to a UNO on the receive side, and teensy 3.6 on the sender side. However, no dice. The UNO doesn't receive any data or even try to ...
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2answers
71 views

threshold voltage level and blinking problem

I am using arduino pro mini 3.3 V,8 Mhz.vcc of the this arduino is coming from AC-DC converter with regulator 3.3 volt.I am listening analog data from voltage divider approximately 250 milivolts. I ...
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1answer
26 views

How to build an µC controlled power regulator?

The idea: Use an Arduino-like µC to control a set of CPU fans by control the voltage the CPU fans receive. My question: How can I do this in an easy way? Yes, I know, there is PWM but this is not ...
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2answers
2k views

How can I tell the resistance of an internal pull-up resistor?

I have a SparkFun ESP8266 Thing Dev board, to which I want to perform a digitalRead() on one of the GPIO ports. I'm using D15, and I'm configuring it for input like this pinMode(15, INPUT_PULLUP); ...
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1answer
86 views

3V Arduino options

I have an Arduino Mega board to test 3V devices. Which is the simplest way to connect those 3V devices to the Arduino Mega (it works at 5V) without burning them? I saw the Adafruit Trinket works at 3V,...
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2answers
86 views

How would I go about measuring an analog signal on my arduino mega that has both positive and negative voltages

I have a signal that fluctuates between -70mV and 50mV. How would I get the arduino to read this.. Ultimately I am trying to graph the data in real time so it looks like this. https://imgur.com/a/...
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2answers
91 views

Fluctuating voltage coming out of arduino uno 3.3 output pin [closed]

Problem with my arduino is when I check voltage of 3.3 volt pin using multimeter , voltage varries a lot from 1.5v upto 5v. Due to which esp8266 wifi module connected to this 3.3v pin gets very hot. ...
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2answers
201 views

Waveshare 1.54 inch ePaper display requires 5Vs from Arduino Uno

I have an Arduino Uno and I would like to attach a Waveshare 1.54“ display (red, black & white) to it. All the specs tell me that it consumes 3.3 V which I have readily available on the Arduino ...
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1answer
377 views

Arduino YUN Rev. 2 power supply

I want to connect my YUN Rev. 2 to 7.4V. I read that the older version only provides exactly 5 V at the Vin Pin. Is the Rev. 2 similar to it? I read that the power supply should be improved, but what ...
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1answer
130 views

The need to use logic level converter

Why do we need level logic converter to have 5V or 3.3V? Because in Arduino Uno/Mega (don't know about other boards), they already provide 5V and 3.3V for us to use.
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1answer
1k views

Read frequency of input in digital pins

This is a somewhat theoretical question: Let's say I have some sensor that sends digital signals to one of Arduino's digital ports. Now, I don't know the frequency it sends those signals in. For ...
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1answer
577 views

YL-38 output to NodeMCU v1.0 analog input

Using a YL-38 and NodeMCU v1.0 I am trying to achieve what the first link is doing, take a soil moisture reading. I've done this on an arduino, but the conversion from an arduino nano to a nodemcu is ...
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3answers
117 views

nrf24l01 fried when supplying 6.5V to VIN?

I have two Arduino Unos (One clone, one genuine) and I'm trying to make a remote and a base station. Got everything working flawlessly, (Using RF24 library) and the last piece of the wiring was to get ...
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1answer
879 views

How can I create a battery level circuit

Im trying to create a circuit so that I can monitor the voltage drop on my battery and send an message when the voltage drop reaches the drop out. But I'm having some problems with my voltage ...
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2answers
92 views

3.3V from 5.0v outlet

I am working with an Adafruit Feather 32u4 FONA board. I want to connect a GPS module I have worked with before (3.3V required) but am not having much luck. I have studied the pinout of the board and ...
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2answers
40 views

Input voltage from circuit drops despite Arduino turned off

I'm using an Arduino Uno to emulate an old Atari disk drive as described here: http://whizzosoftware.com/sio2arduino/ As both the Atari and the Arduino use 5V TTL serial communication, the hardware ...
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2answers
82 views

How much low analog voltage can Arduino uno read?

Today I was playing around with arduino analog voltage ranges, the error in output with respect to a digital multimeter started to happen when the reading was around 0.0014volts. How much low an ...
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1answer
80 views

How to change the value within a variable using math? [closed]

I'm up to Lesson 11 in the TopTechBoy tutorial: https://www.youtube.com/watch?v=afurKLOqqSg Lesson 11 : http://www.toptechboy.com/arduino/lesson-11-arduino-circuit-to-dim-led-with-potentiometer/ I ...
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1answer
72 views

Capacitors, Arduinos and Saving Data

In short, I have programmed and wired a speed/odometer and all is working well. However, I need to save data from the components/sensors once a power button is pressed, which has led me down the road ...
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1answer
153 views

Teensy 2.0 with MCP23017-E

I've recently bought two more MCP23017-E's for a project, but after hooking them up to my Teensy 2.0 I couldn't get them to react to anything. Suspecting faulty hardware, I hooked them up to an old ...
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1answer
71 views

3.3v Arduino I2C communication with motor controller powered at ~6v

I am trying to just use the voltage from 4 Alkaline AA batteries in series (6v nominal) to power a motor with the TI drv8830 IC. My question is, will this circuit (specifically just pulling the sda ...
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1answer
1k views

Two batteries sharing ground?

I need to power my arduino and 2 DC motors requiring 6V each, I want to power the DC motors with a 6V battery through the vM pin on an h-bridge and use a 9V battery to power the Arduino itself. On my ...
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2answers
3k views

How to measure the supply voltage of Arduino without using an analog pin

I'm using Arduino Nano to measure temperature with a 10 kohm thermistor and a voltage divider. My problem is I'm getting only 4.2V on the 5V pin. The power is supplied via a USB cable from a desktop ...
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1answer
98 views

powering arduino with a voltage divider to increase lifespan

I have a chinese arduino nano that I'm planning to use to open a door using a numeric keypad. My power source is 12V and I want it running 24/7. I have read that the first thing to fail on an arduino ...
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2answers
2k views

Getting 3.3v on 5v pin in Arduino Uno

When interfacing my Arduino Uno with a relay I was facing reliability issues, and while investigating it with a multimeter, I found something strange. I noticed that in the 5V power pin (with which I ...
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0answers
356 views

NPN transistors level shifter [closed]

I'm going to use this for Arduino Pro Mini (5v version) to communicate with ESP32 via UART so I need level shifting. I found this circuit which uses NPN transistor and I'm also going to use it. This ...
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1answer
412 views

Getting the voltage of an 18650 battery with an Arduino

I'm using a Arduino Pro Mini (5v) to sense the voltage of an 18650 battery. The battery (that is being sensed)is also used to power the Pro Mini but the MCU is behind a boost-converter which outputs 5....
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1answer
793 views

Electric meter pulse counting using LLC

I am trying to create an electric meter reading setup for Arduino, and I have been searching for it and almost every posts available is using LDR sensor. http://www.reuk.co.uk/wordpress/solar/...
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276 views

Serial communication between two microcontrollers w/ separate power supplies

Fair warning: I'm an electronics n00b. I'm trying to get an Arduino Uno R3 to send data over 9600 baud serial to a Wemos D1 Mini Pro. What worked (mostly): Powering (5V) Arduino off a 4 AA barrel ...
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1answer
136 views

Why is there a third connection to the host in this 3 wire current output sensor diagram?

I've got a 3 wire 4-20mA current output sensor, externally powered by 12V, which I want to read from an Arduino Uno (5V). The sensor connection diagram is below, but I don't understand why it says to ...
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2answers
126 views

3.3V Conversion [closed]

I'm writing a SPI Master module for my FPGA and I would like test it with my Arduino Uno. What's the problem? My FPGA has 3.3V logic and Arduino has 5V TTL logic. So, what's the simplest solution to ...
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2answers
494 views

Does the Arduino Yun have to be powered exactly at 5V?

I'm working on a senior project and I am using a ATX PSU to supply power to the Arduino Yun and other components. If I'm not mistaken, its powered through the usb. I took a usb cord, strip the sheath ...
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2answers
266 views

Multiple LED on arduino [closed]

I am currently trying to control multiple LEDs with one Arduino Mega 2560 board. However, since each LED needs 3.6 volts and the board only supplies 5V I cannot make more than one light up. Is there ...
2
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1answer
452 views

This logic level converter does not want to work

I got this logic level converter to be able to use my lcd but I can't figure out how to get it to work, the problem is that the current is not passing through. This is the model: TXS0108E Any help is ...
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2answers
86 views

Arduino Voltage Divider

So am doing a project which involves the reading of voltage and current generated by Solar Panel. Now I learnt that Arduino cant Read Voltage directly above 5V. To read above that you need to add a ...
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3answers
294 views

What options do I have to get 5v on my current project?

I'm very new to arduino and have started work on my first project, a simple little web server. I'm using a NodeMCU with an sd card module and screen. The issue is that in order to power my sd card ...
2
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1answer
194 views

How to switch a low-voltage (1.5V) toy motor with an arduino?

I would like to add an Arduino to control a toy with a 1.5V battery and motor in it. The toy is currently controlled by a SPST switch in series with a single 1.5V AA battery and a cheap motor. I ...
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0answers
573 views

Using 5V microphone module with Wemos D1 Mini Pro 3.3V analog pin

I want to read values from this microphone module using Wemos D1 Mini Pro analog pin. Unfortunately, this module operates on 5V, but the analog pin on Wemos has range 0-3.3V. I have tried to use a ...