Questions tagged [measuring]

Use this tag if your question relates to measuring, eg., via a sensor.

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Frequency counter with external reference

I'd want to use the RPi-pico to measure the ratio between two frequencies, one stable F0 = 10MHz, the other F1 about 14MHz, both externally fed to two GPIOs. 20 bit accuracy is fine. That could be e.g....
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2 answers
68 views

Get Measurements from Battery/Solar Setup

I'm planning a setup with an rpi3b+ and the pijuice hat (battery) and pijuice solar module. It is key to my project that I can access the following data digitally i.e. in the pi: current power ...
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what is the relationship between worst case execution time (WCET) and cpu utilization of a raspberry pi zero

Assuming the task execution in case of single core processor be sequential, how can we possible relate the WCET of any program to CPU utilization of task and/or core frequency at which the task is ...
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1 answer
106 views

Software-Based I2C Cannot Control Clock Speed

I'm using a Raspberry Pi 4B to read pressure sensors via I2C, with Python 3.7.3 and the SMBus library. I ran into the Broadcom clock-stretching bug, so I switched to software-based I2C (brief ...
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Change DVFS scale on raspberry pi in real time from the CLI?

I am creating an app that will showcase the power efficiency of the raspberry pi with different DVFS scaling. I am wondering whether there is an option to change the settings from the CLI, since that ...
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2 answers
113 views

Raspberry Pi 4b- powerbank measure

I want to power my Raspberry Pi 4b with a powerbank. I know that I need a 3A powerbank. The question is: How can I measure it? I want to get a percentage of it (which will be displayed over a website)....
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1 vote
0 answers
533 views

Raspberry Pico RP2040 - Circuitpython ULAB FFT Frequencies

I am trying to properly perform FFT and calculate frequencies on my PICO using CircuitPython's (CP) ULAB library: ULAB FFT With traditional Python using NUMPY and SCIPY, this is easily achievable, ...
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1 vote
0 answers
128 views

How to use Rpi SPI MCP3008 ADC to read visual light LED's transmit and receive signals?

EDIT: Firstly I wrote it a bit confusing way. So let me summarize my problem. This is something like answer to comment bellow. (1) I am trying to make somethin like visible light communication based ...
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Can I have different frequencies on different pins on Raspberry pi?

I am trying to configure two pins on Raspberry pi 4 with different frequencies (one being half of the other). How can I do that? Thanks in advance
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1 answer
148 views

How to list all RPI frequencies' settings?

I've been playing with overclocking in the last 2 days. I'm helping myself with this list. Yesterday I came across a command which lists all of these parameters and the frequencies which are currently ...
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Cannot change individiual core frequency on Raspberry with cpufreq-set

I used to use cpufreq-set to change the cores' frequency individually on my RPi 3B+, but I noticed that recently I cannot do it anymore. The effect of: sudo cpufreq-set -c 2 -f 1400000 is the change ...
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1 answer
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why frequency output is not constant?

[![I uploaded piscope image and same time output image also for better understanding of issues][1]][1]I am using sample code of Pypi from "http://abyz.co.uk/rpi/pigpio/python.html" to detect ...
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0 answers
206 views

DS18B20 does not have a unique adress in /sys/bus/w1/devices

The problem: I am trying to use a RW1820 (DS18B20), to display the temperature. yet it does not show up in devices. Only w1_bus_master 1 appears. Setup: Raspberry Pi 4 1-Wire Temperature Sensor ...
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4 votes
4 answers
2k views

Voltage monitoring of battery pack (i.e. before voltage regulation)

I am looking to use four 18650 batteries and a step-down DC-DC converter to power my Raspberry Pi 4. The negative terminal of the DC-DC converter is common for the input and the output. I would like a ...
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2 votes
1 answer
233 views

Direct reading from i2c

I am attempting to increase the frequency at which I read samples from the I2C dedicated pins. I have attempted this through the wiringPi library (C code), from which I reached just about 900Hz. As ...
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4 votes
1 answer
569 views

Reading Frequencies with Python

hello ladies and gents. your knowledge helped me a lot until now but now i have a question. i want to read out the frequency of a 3.3V squarewave. (The unit i want to readout is a capacitive ...
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0 answers
690 views

AC Frequency Monitoring

There are multiple hardware solutions to do amp/current monitoring, but I cant seem to find one to do AC Frequency monitoring. Anyone have a pointer to board that can handle line power and return line ...
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1 vote
1 answer
939 views

How can Rpi4B python UART talk to XY PWM Signal Generators?

Currently I am trying to automate a coil winding machine using stepper motors. I wrote a Python code to send frequencies to the stepper motors. But for some reason, the frequencies produced by ...
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1 vote
1 answer
70 views

Share data between different

I'm building a floor heating control with raspberry pis. Until now I have two Pis working, one which controls the valves via relays and another which works as "central" with a webinterface to adjust ...
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1 vote
2 answers
363 views

Raspberrypi unable to read 2000 PPR encoder

I am using a DC motor attached with a 2000 PPR incremental encoder. I am using RPI to count the number of ticks, my code works fine but I am not able to calculate all the 2000 ticks. Any help would be ...
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1 vote
1 answer
98 views

Not able count Pulses Generated by PLC

I am using the below code to capture the pulses and count pulses for a specified interval but the output not as what i expected. For every pulse it is giving uncertain value. The pulse i want to ...
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1 answer
234 views

No thermal throttling in Raspberry Pi 3 model B?

I am seeing that the thermal throttling doesn't work while you read the frequency from: /sys/devices/system/cpu/cpu*/cpufreq/cpuinfo_cur_freq And thermal information from: /sys/class/thermal/...
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1 answer
231 views

Fluctuating SCLK voltage with increase in frequency

Raspberry pi newbie here. As part of my academics i was working on Raspberry Pi 3 B+ , Raspbian OS kernel 4.14.98-v7 and i was testing protocols and i am stuck at SPI. I am running spidev_test.c from ...
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2 votes
2 answers
154 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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1 answer
72 views

connect 4 measuring devices output to a raspberry and set a Pin high if value exceed a particular value

I have a special measuring system. Each measuring unit gives PWM output (total 4 outputs). Maximum frequency will be 10Khz (for each output). I wanna measure the frequency of each PWM evey second ...
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0 votes
1 answer
76 views

Raspberry Pi 2 power consumption incorrectly

Before, i'd a problem about changing governor for my Pi (cpu always stays at 600Mhz in every mode), after doing some tweaking, i'd already make it up to 900Mhz. However, now i'm using a power-meter to ...
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1 vote
1 answer
1k views

Saving measured data to text file

Im using an ADC to measuring values and send them over a socket via the RP, yet I also want to save the values to my RP as I'm reading them. For some reason when I open the text file it only has the ...
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-1 votes
2 answers
1k views

Count time between two pulses in nano seconds

How can i count time between two pulses in nano seconds by using raspberry pi?
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-2 votes
1 answer
475 views

Energy consumption measurement using ACS current sensor [closed]

I want to build an energy consumption meter using my Raspberry Pi. I have done some research, and determined that the ACS712 current sensor could be interfaced with my RPi for this purpose. I do not ...
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0 answers
3k views

Is there a way to check out the GPU usage (how busy it is) on a RPi3? [duplicate]

I have a Raspberry Pi 3 Model B and would like to know how busy the GPU gets when I run certain tests to determine whether it would be possible for me to do certain things. I see that the GPU is a bit ...
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1 vote
2 answers
736 views

How do I connect an S beam load cell to a raspberry pi 3 and then to my Laptop?

I am a university masters student who is currently working with a group of mechanical engineers to built a tabletop tensile and fatigue testing machine. To measure the forces being applied to a sample ...
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0 answers
70 views

graph time vs frequency

I am in search of a code which can display the real time graph. I am going to display the microphone input signal in frequency vs time domain. The function that I am expecting is same as the vocal ...
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1 answer
2k views

code to read live mic input audio frequency

My project is to create a kit to play recorded (music chords) audio file automatically changed with respect to frequency of live microphone input with a certain period.This will help the solo singers ...
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1 vote
1 answer
2k views

Why is my zero SPI clock frequency different than requested?

Using the SPIdev, I have setup the SPI clock frequency, but measuring the real signal frequency using oscilloscope shows, it differs extremely to the expectations. How is this possible? spi_fd = open(...
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3 votes
1 answer
6k views

Does Raspberry Pi 3.0 support HDMI 2.0 standard?

I am not able to see specific protocol version of HDMI (1.4 or 2.0) supported by RPI 3.0. Basically I want to take HDMI 2.0 output from RPI and provide it to my device. Also can we measure the rate ...
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0 answers
872 views

Incremental Encoder / Frequency

Can anyone help. I have a raspberrypi3 with a photoelectric sensor and a 600ppr encoder hooked up. Everything is up and running, im using pigpio to capture my pulses from the encoder and using the ...
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0 votes
2 answers
374 views

Pigpio belt speed encoder

I'm trying to read pulses from an encoder to measure belt speed. My encoder is 500 ppr. I have approx 2400 pulses per meter and I need to measure speeds upto 450 meters per minute. Can anyone help ...
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1 vote
0 answers
81 views

Detect voltage using Raspberry Pi [duplicate]

Background My cottage has a cellar which is relatively humid, so I purchased a system that keeps the humidity at reasonable levels using a set of fans and a dehumidifier. The system runs two ...
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1 vote
1 answer
948 views

What sensors do i need to use to measure density? [closed]

I want to measure the density of object and I need to get the volume and weight of the object. What sensors do I use to measure density?
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0 votes
2 answers
3k views

Vehicle 12v detection or measurement

I have an idea that involves detecting and possibly measuring a 12v feed from a car but my electrics skills are a little limited and I'm using this idea to learn. My understanding is that the 12v feed ...
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0 votes
2 answers
996 views

How can I measure current with RPi at high voltage/high current (100-120V / 0-30A)

How could I measure current with a raspberry pi at voltages and currents that can be found inside a typical home's power outlets? The goal is to create a device that monitors how much energy is being ...
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16 votes
2 answers
4k views

Measure RPi3 power consumption without external hardware

I power my RPi3 using a power bank for smartphones, and I'd like to check how much power the Pi draws from it while my project is running. I don't have any special equipment for power measurement. Is ...
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-1 votes
1 answer
1k views

how to measure length [closed]

I want to measure the number of meters of running cloth off of a fabric roll. So that when I press a button a motor spins a roll of cloth and the fabric is rolled onto a separate roll. I want to be ...
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4 votes
5 answers
5k views

How to read values from an clamp-on ammeter with an raspberry pi?

I want to use a clamp-on ammeter (like this one) to detect whether a table saw (230V) is switched on or not. The clamp-on ammeter is meant to be used with a volt meter and has an 1 mVAC / A output ...
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1 vote
0 answers
794 views

Measure input voltage of Raspberry Pi B+ running Ubuntu

I just learned that a red flashing LED indicates voltage below 4.63V on a Raspberry Pi Model B+. Thus, the Pi seems to "know" about it's input voltage. So my question is: Is there a command to ...
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0 votes
1 answer
327 views

Does RB URF02 ultra sonic sensor give false readings?

There's only 1 raspberry pi shop in my country and he offers only two ultra sonic sensors HC - SR04 and RB URF02 there's a pdf on the pages I linked to for more information. RB URF02 is so much more ...
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6 votes
3 answers
27k views

Count RPM/Frequency/Pulses on GPIO ports (Maximum?)

I'm planning to count the RPM of a RC Car which is controlled with a PI B+. But while planning the question occurs, how to count the RPM. My Idea is via a Sensor, which gives a Pulse every Round, and ...
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2 votes
2 answers
13k views

Measuring frequency via GPIO

I'm trying to input the frequency of a 3.3V square wave on a GPIO pin as a program feedback parameter. The input frequency range would be 1000 to 100,000 Hz and data polling would happen at 30 Hz. ...
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2 votes
2 answers
9k views

How to measure DC current RPi?

I have recently bought a Raspberry Pi, and I would like to be able to measure the current flowing through the circuit in our Greenpower electric racing car. It would also be useful to record this for ...
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2 votes
1 answer
230 views

Can GPIO measure 3-10ms input spike?

I want to measure speed with one infra gate. The width of the bypassing object is known therefore I could calculate the speed. However the infrared gate would be interrupted only for 3-10ms. I ...
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