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Questions tagged [voltage]

The tag has no usage guidance.

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16 views

5v pin usage for 433mz transmitter receiver

I've bought a 433mhz transmitter receiver and I made a check on model SODIAL(R) 015274A2 the strange is in two links we have 2 differente specs, one says: https://www.amazon.com/SODIAL-433Mhz-...
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2answers
132 views

FM transmitter antenna length

I'm a new raspi user, and I'm starting to build some projects with hardware. I would like to try this FM radio station for example, but I have a doubt about the antenna's length. This is important ...
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2answers
204 views

Get reading of RPI supply voltage

On the most recent pi I've been playing with I've noticed the under-voltage lightning bolt warning, discussed on this question. My question is whether there's a way I can access the voltage reading ...
0
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1answer
25 views

PWM and Output Voltages at High[er] Frequencies

I am attempting to set an analog voltage control signal with a Rasberry Pi 3 B+. My Python 3 script uses RPi.GPIO to output PWM across a range of duty cycles to simulate analog output---without the ...
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2answers
50 views

How to increase voltage of USB ports on the Raspberry Pi 3 Model B?

I have been trying to build a Raspberry Pi laptop, and I found an issue where my screen required power at all times to run , so I decided to plug the screen in to the USB port in the Raspberry Pi. ...
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2answers
26 views

Ground running back through logic shifter?

Sorry if this is a silly 'beginner' question, but I'm still only just getting into working with the Pi. I have a Pi Zero that I want to use to drive a module of a few WS2812 LEDs. Because the GPIO ...
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1answer
157 views

Pi 2B, Under-voltage detected!, no lightening bolt, +5 is rock solid at 5.01VDC

This is a weird one - have had 2B in service for three years, but it crashed last week. Rebuilt with a new Pi 2B+, but saw undervolt errors on the rebuilt system that would have gone unnoticed, so ...
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2answers
351 views

Powering a sensor using an external power supply board

In my Raspberry Pi project, I need to measure a distance. To do that, I have an ultrasound sensor called "AJ-SR04M" (it is basically a waterproof HC-SR04 I believe). Characteristics of the AJ-SR04M: ...
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1answer
52 views

Why my gpio input changes the internal resistance when running the python code? [closed]

I have a raspberry pi receiving inputs with a 300k resistance connected between the voltage input (12V) and the gpio. When my python code is not running the voltage at the gpio is 1.7v, but when I ...
1
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1answer
65 views

Supply voltage 5V issue from Raspberry Pi 3

I have a sensor connected to a Raspberry Pi 3 and I see some variations of the signals which is not expected. These variations seems to be due to the supply voltage 5 V from the Raspberry Pi. ...
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3answers
756 views

Powering RPI 3 and using relay from same source

I want to build something of a smart home device such as a smart switch /outlet for example that controls something like a light. However, I don't know what the wiring should be Like, if it's possible....
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1answer
188 views

GPIO Voltage tolerance for input

I don't managed to find the input tolerance on I/O pins, especially on the Input pins. If I apply a voltage 3,6v (3.3v +0.3) on an input will it be dangerous or is it ok ? If somebody have a technical ...
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3answers
248 views

Turn on and off 5V to 12V Relay

I want to use my Raspberry Pi to turn on and off a 12V current for a certain amount of time. I've read a lot on this forum and I've understood that the 5V GPIO Pin is... Not GPIO, meaning that I ...
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0answers
46 views

Pin on off engine javascript nodejs

I have a little engine linked at pin 1 and 3. How can I turn it on and off throught nodejs? Is there also a way to control how many volts are sent (to make the engine faster or slower)?
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1answer
40 views

Raspberry Pi3 using different ground pins for multi ldr toy car

I am working on a toy car which is following the "light" and I am totally new at raspberry pi and circuits. In this video, he is using 1 ldr. I need 3-4 ldr to turn the car to left or right. (I am ...
4
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1answer
733 views

Undervoltage symbol

So I have this undervoltage symbol on my raspberry 3+, and it's annoying. Now I have a powerbank with 5V and 2.1A(fast charger) and the symbol is there as well as on the old pi-2b+ AC adapter. So ...
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2answers
255 views

DAC MCP4725 not working with raspberry

I am using raspberry pi 3. I am trying to run the AC induction motor for that I want an analog pin. In raspberry pi model doesn't have an analog pin. All pins are digital IO pins. So I have tried MCP ...
1
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1answer
154 views

Will accidentally powering a pi with more than 5V break it?

I have a variable power source(5V, 6V, 9V, 12V, etc...) with a usb plug which I had powering my pi 3B a few months ago, but one day (a few months ago) I accidently had the power source set on 6V(it ...
4
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1answer
95 views

Raspberry Pi's reaction to 7.2 Volts applied to a GPIO pin?

I was using a Raspberry Pi 3 model B in a project. The Pi was connecting to a web socket and receiving data from the user on a PC or whatever device connected to the same socket. It was fine at first....
2
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1answer
235 views

GPIO pins are always low

I'm using a Raspberry Pi 3 Model B running Raspbian Stretch Using it somewhat like an RC car with an L298N H-bridge motor driver to control two DC motors. It was working fine until a few days ago ...
0
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1answer
98 views

Where to connect PWR_LOW_N?

We're developing a compute module board, and added the undervoltage circuit. Unfortunately, I cannot find where to PWR_LOW_N is actually connected. I have found some saying it's connected to GPIO 35 ...
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2answers
3k views

Pi 3 Model B+ doesn't boot - Power Supply or broken?

I just bought a Raspberry Pi 3 Model B+. I also bought a power supply that the reseller sold specifically for the Pi - it delivers up to 3A. However, the Pi doesn't boot. I gives me the rainbow screen ...
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0answers
1k views

How do you check the battery level of an external battery and display it through software? [duplicate]

I'm building a mobile device via a raspberry pi 3, and I need it to be able to display the battery life on the screen and shut down safely when the battery is below 5%. I believe this may require an ...
0
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1answer
53 views

GPIO is not giving maximum 3v3 output

I have a raspberry pi model B, NO B+ OR 2B, jus the model B. I am using it as a brain for a robot but I’m having a little trouble with the motors. I am using the GPIO pins to power it but when I set ...
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0answers
87 views

Raspberry Pi 3 not booting - no LED's, hot CPU

Hey everyone :) I've just encountered a strange problem. My Raspberry Pi 3 V1.2 is not booting anymore. The LED's don't flash at all, the CPU becomes hot and the voltages are kind of wrong. On the 5V ...
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1answer
81 views

Noob Looking to detect LED voltage 0v LOW, 1.8v HIGH on another device

Trying to learn about the PI and I have acquired a pi Zero W with the GPIO header. I have an external device that signals activity via an LED, which blinks @ 1.8v 2X and then remains on until reset, ...
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1answer
200 views

Precision of Raspberry Pi GPIO outputs voltages [closed]

Raspberry Pi has several output voltages, GPIO outputs theoretically giving exactly 0V for False and exactly 3.3V for True, 3.3V line and 5V line. However, how precise are these outputs? Can the ...
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0answers
29 views

Raspberry pi dome light with relay

I have an after market media/LCD screen which hooks up to my dome light. I want to hook up my raspberry pi through HDMI. I'm going to 3D print a case to sit along side my LCD media player. My goal is ...
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0answers
42 views

Raspberry Pi Zero Can't Sense the voltage generated by Piezo Element, Can We amplify the voltage ? If Yes then How?

I am trying to make a Knock sensor using piezo element. I have a Raspberry Pi Model zero W. The Problem faced is : Raspberry Pi is unable to Sense the voltage generated by the Piezo element. This is ...
5
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2answers
2k views

TP1/TP2 equivalent for Raspberry Pi 3 B

Is there "old" TP1/TP2 equivalent for Raspberry 3 Model B to measure voltage?
3
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4answers
943 views

Raspberry Pi GPIO input voltage Limit

I am doing a project in which I have a component that outputs a 5 Volt signal. Since the Pi is only able to handle 3.3 V I connected the signal to a voltage divider. I used a 4.7 kiloOhm and a 2.2 ...
1
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1answer
240 views

Inconsistent i2c bus address listings causing sensor reading issues

I am using a raspberry pi 3 with an Atlas Scientific DO sensor to try and create a wireless sensor network for an aquaponics system. Everything works fine when I am running the system in my home in a ...
1
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0answers
294 views

Issues using SPI pins on Raspberry Pi 3 with MCP3008 ADC for Voltage Sensor [closed]

I am trying to create a voltage sensor using a Raspberry Pi 3 with Raspbian (February 2017 release because that is the one I need for the rest of my project) by connecting the SPI pins to an MCP3008 ...
0
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1answer
649 views

3.3v to GPIO input using relay

I'm exploring various ways to detect higher voltage using the Pi and have come up with a circuit where the 5v would energize the coil of a relay which would switch 3.3v from the Pi's internal 3.3v ...
2
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3answers
396 views

Detecting 5v from external source using voltage divider

I'm working on detecting whether or not an external 5v supply is on or off and found a few helpful related questions, specifically this one: Detecting 5V output from USB charger via Raspberry Pi From ...
4
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3answers
2k views

Calculating resistor value for transistor

I'm creating a circuit with an infrared led and a transistor connected to a gpio pin. I'm currently using 5v with a 40 ohm resistor (four 10 ohm resistors chained) but I'm not sure what resistor to ...
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2answers
257 views

Connection of 220V Doorbell to Raspberry Pi GPIO

I have a power connection going from a button outside of my house to the doorbell box. I want to take a branch of this wire, and connect it to a raspberry pi to detect the button being clicked. The ...
3
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2answers
320 views

Voltage on undefined GPIO pin

If I do not specify the output of GPIO pin (like GPIO.output(4, False)), I always have a voltage of 1.3V on this pin How can I set all pins to 0v? and why are undefined pins have this voltage of 1....
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1answer
43 views

LEDs won't follow pattern (voltage issue?) with Pi 3

First and foremost, let me say that I'm new to electronics and the Raspberry Pi. I'm a programmer. I have never done this type of project before. Now, I have a Raspberry Pi 3 model B that controls my ...
0
votes
1answer
444 views

Measuring 0-5 V DC with a good accuracy (~10 mV) using a Raspberry Pi

I'm totally new to Raspberry Pi and I want to use it for an important school project. My aim is to build a laser-seismograph using a laser pointer and 4 photodiodes which basically measure the laser'...
0
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0answers
178 views

How to determine if a USB power supply is safe to use with a Raspberry Pi?

I have a Raspberry Pi 3 that appears to have been destroyed this morning. I purchased a no-brand USB mains charger suitable for UK use (and CE certified) from eBay, and I am almost certain that was ...
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1answer
205 views

What Circuit Should I Use to Hardwire Raspberry Pi to Doorbell?

I am trying to connect my raspberry pi to my hardwired doorbell in order to send a text message when the doorbell button is pushed. I have successfully sent the text message using a button connected ...
1
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1answer
509 views

How to check if 16x2 LCD is 5 volts or 3.3 volts?

I got a 16x2 LCD display but I have no clue if it's 5 volt or 3.3 volt logic. I'd like to use it on a Raspberry Pi but I'm afraid to just plug it into the 3.3 volts if the display is 5 volt. The ...