Questions tagged [voltage]

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2answers
49 views

Convert 12V to 5V to power RaspberryPi

I have an Eleksmaker laser cutter which has a board with a 12V output (see top of image). I would like to power my RaspberryPi using this 12V output. What is the advantage of powering the ...
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2answers
69 views

What happens to the GPIO voltage after shutdown?

I don't have a Raspberry Pi laying around at the moment and I would like to detect if my Raspberry Pi is shuted down. My Idea is that maybe after the Pi shutted down the Voltage at the 3V3 pin will ...
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2answers
38 views

Measure Volt, Amps, Watt and Kwh of an external 12V system

I saw online some cheap hardware ~10$ that can measure Volt, Amps, Watt and Kwh and display the results on an LCD screen. I could buy and plug these on my 12V solar panel system to monitor it. (5 of ...
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1answer
50 views

Is there a piece of hardware which enables hotplugging sensors to the breadboard?

The idea is the following: I have a Raspberry PI connected to a breadboard. To this breadboard, I would like to connect (digital and analog) sensors and actuators while the PI is running. Or remove ...
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2answers
49 views

Voltage dropped significantly on GPIO 4 with a relay coil

I have a Raspberry PI 3 B+, and when I activate the GPIO 4 as output and checking agains a multimeter I get its 3.3V as expected. If I connect the GPIO4 to one end of a coil (http://www....
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0answers
20 views

LCD Installation freeze because of low voltage?

i try to install my LCD 3.5 waveshare, but when extracting the folder and use sudo ./LCD35-show it starts shortly and then freeze. I Got the thunder icon and the freezed screen. Might this be the ...
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3answers
53 views

GPIO to detect if external 5v source is turned on or off?

I'm using a Pi Zero W and I'd like to connect a 5v source to a GPIO pin to detect if the 5v is on or off. I know the GPIO is only digital I/O and 3.3v max, so is a simple voltage divider enough or do ...
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2answers
56 views

Is 5V out on the Pi Zero W unregulated?

I want to power a 5V relay breakout board from a Pi Zero W. I believe the 5V pads are "raw" and a "pass through" voltage? Is this correct?
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3answers
75 views

MCP3008 minimum current(resistors value)

I want to measure some battery voltage in a range 0V-4.2V with MCP3008(VDD=VREF=3.3V). I used a voltage divider with R1=2.7MOhm and R2=8.2MOhm, but it didn't return correct value, I used resistors ...
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1answer
98 views

Seeed ADC (ADS1115) with Raspberry Pi 3 B+to read voltage values using python3

I'm using a Seeed 4-Channel 16-Bit ADC (ADS1115) for Raspberry Pi with a Stretch installed Raspberry Pi 3 B+ and successfully configured following below guidelines & GitHub. http://wiki....
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2answers
214 views

Water Level Detection Sensor 3.3 Volt vs. 5 Volt

I'm using a classic Water Level Detection Sensor or sometimes called Rain Water Level Sensor together with a RPI 3+ to detect water in a Pot (Link). So I don't need any analog reading but only the ...
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2answers
259 views

Reading Voltage Input on ADC

I'm thinking of using the Waveshare ADC board with a RaspPi 3 to monitor the current driving a DC brushless motor. I've run through the waveshare examples, and I can handle reading inputs ...
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1answer
113 views

is undervoltage on a pi3b+ a problem of the board?

Like many others I got the undervoltage warning on a pi3b+. I see most answers blame a poor power supply. I plugged mine to a bench power supply to test this, I set it to 4 amp and kept getting ...
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0answers
76 views

Control 12V motor from 3.3V GPIO with external 12V Power Supply

I have a 12V motor, which I need to control from my Raspberry Pi (through the RaspiRobot Board). However, the RaspiRobot Board gives me only 3.3V for the motor. At the same time, I have a 12V adapter ...
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0answers
36 views

Checking Voltage Level at GPIO Pin Program

I’m trying to write a program that will loop through 3 GPIO pins connected to an external charging pad and see if a device has been placed on the pad (high voltage). If high signal is detected the ...
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2answers
179 views

Turn a Raspberry Pi into a voltage tester

I would like to create a voltage tester like the one described in this video, using 555 ic, and then connect it to Raspberry Pi, in order to log the frequency a 220V waterpump is switched on. My ...
1
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1answer
64 views

Wiring that won't damage my pi [closed]

A while ago, I decided to wire up a Raspberry Pi (Zero W) to a few peripherals, but it stopped working shortly afterward (not entirely, but I think it was undervolting the power rails). I had ...
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1answer
35 views

Lipo Battery Voltage Drop When Pi 3B and LCD Screen Are Both Connected to Powerboost 1000

I have a Raspberry Pi 3B and LCD Controller Board connected to a Powerboost 1000 Basic. A Lipo Battery Charger is connected to the Powerboost as well. I noticed if I remove the LCD Controller board ...
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0answers
41 views

Is it possible to plug in and out sensors, LED-s etc. on the breadboard while the Raspberry is running?

What I would like to do, is to let the Raspberry Pi run and while it is running, connect and disconnect eg. sensors whenever I please to/from the breadboard WITHOUT turning off/disconnecting the Pi ...
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1answer
44 views

Raspberry PI Portable USB Charger [duplicate]

I bought a $5 usb charger that I am using to power my Raspberry Pi. The charger works decently but I am noticing that every once in while the raspberry pi will reboot. I have read that some chargers ...
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0answers
28 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
607 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
2k 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 ...
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1answer
212 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
162 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
31 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
416 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 ...
2
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2answers
719 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: ...
0
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1answer
61 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 ...
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1answer
94 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
1k 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
578 views

GPIO Voltage tolerance for input

I have not been able 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 ? Does somebody have a ...
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3answers
517 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
101 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
66 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 ...
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1answer
1k 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
416 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
336 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 ...
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1answer
97 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
380 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 ...
1
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1answer
125 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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1answer
63 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 ...
0
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1answer
101 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
331 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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2answers
3k views

TP1/TP2 equivalent for Raspberry Pi 3 B

Is there "old" TP1/TP2 equivalent for Raspberry 3 Model B to measure voltage?
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4answers
2k 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 ...
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1answer
392 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
383 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
857 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 ...