Questions tagged [pwm]

Pulse-Width Modulation (PWM) is a technique used for controlling the power given to electrical devices. The average power supplied is controlled by rapidly turning the supply on and off. Questions here concern driving PWM outputs from the Raspberry Pi.

Filter by
Sorted by
Tagged with
2
votes
1answer
333 views

Generating fast rise PWM signals using software GPIO

I want to use my Raspberry Pi 3 Model B (rev 1.2) as a source for fast rise PWM signal generation. The idea is to utilize RPi as part of a cheap TDR (time-domain reflectometry) setup. For anyone ...
1
vote
1answer
283 views

GPIO PWM reset to high

I'm using the pi 3a+ pwm to send sync informations to my music gear. When I stop the pwm, I don't use the pwm.stop(), but rather set the duty cycle to 0. This is because I run the pww from a different ...
0
votes
1answer
288 views

Triggering of MAPIR using PWM signal

I am currently trying to trigger a MAPIR Survey3 NDVI Camera with a PWM Signal. The camera is connected via this HDMI trigger cable. For the camera to trigger I need a 2 ms PWM signal. I have given ...
2
votes
1answer
644 views

Calibrating ESC with PCA9685

I'm currently working on a RPi project to control an RC car via my phone, and I am having difficulty setting up my ESC. Based on research I have done online, I need to first calibrate the ESC by ...
0
votes
1answer
285 views

3 PWM pins for RGB LED

I got an RGB LED, one mass and one for blue, red, green. So I got a list there are only two PWM compatible pins listed. Pin 32(GPIO 12) and pin 33(GPIO 13). But for my RBG LED I need three pins with ...
0
votes
2answers
330 views

How to control speed of dc motor using servoblaster

Im using servoblaster in pcm mode and setting pulsewidth from code for turning my servos position to desired angle. But my question is, cant i use it for controlling the speed of dc motor. I read some ...
0
votes
1answer
104 views

RPIO setting: is DELAY_VIA_PCM a hardware PWM?

So I have a project that is going to use audio and need to do some PWM to control a motor. As I understand it (and I could be very wrong here), there are two chips a pi can use to produce PWM. In ...
0
votes
1answer
71 views

Provision Pwm out makes 3.5mm audio hang

Using pi4j and wiring pi configuring hardware pwm pins for driving servo motors. Also using freetts (speech to text) library for speech. My speaker is actually connected to amplifier to 3.5 mm jack (...
0
votes
1answer
667 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 ...
2
votes
0answers
99 views

Trying to use pigpio wavechains to drive very specific acceleration and deceleration

I'm working on a kinetic sculpture that involves a large pendulum swinging perpetually left to right. I'm using a raspberry pi 3 B+ / arduino uno with a DM860AC to control a nema 34 stepper. I was ...
1
vote
1answer
576 views

How can I control a 12V solenoid door lock - Pi Zero

I have a solenoid door lock that requires 3 different voltages to operate - Unlocked Idle: Requires low voltage (6V) that'll hold the solenoid seated - Locked: No power (0V) - Unlock: 50-100ms ...
0
votes
1answer
1k views

LED pwm fading is flickering

This is how I'm fading some LEDs using a logarithmic function. But with that the LEDs are flickering somehow. I don't understand why... import time import math import RPi.GPIO as GPIO GPIO.setmode(...
1
vote
1answer
255 views

Can I use PWM with hardware audio input?

I know that i cannot use pwm and audio output at the same time, can I use the audio input? I want to move some servos based on an audio trigger signal.
2
votes
1answer
1k views

Using hardware PWM and audio simultaneously

I am developing a project on a Raspberry Pi 3 B+. I am using the PWM0 channel to send a custom-made IR signal using PiGPIO waves. I gather it might then be possible to use PWM1 for mono audio; is that ...
0
votes
1answer
314 views

GPIO.Cleanup() starts motors again after script ends

I have written a script that controls a L298N motor controller, and I have one strange issue with it. When the script ends, one of the two motors do not stop, and instead go full speed in forward ...
0
votes
0answers
100 views

How to generate a hardware PWM wave for driving an LED through RPIO?

I've looked through the documentation of RPIO, and used GPIO18 to get my PWM up and running. This is my code: from RPIO import PWM servo = PWM.Servo() servo.set_servo(18, 4000) As explained in the ...
3
votes
1answer
126 views

pigpio pwm -- gpio <pin_no> bad dutycycle (nnn)

I'm tinkering with the pigpio [C] PWM functions and get ``pio bad dutycycle (nnn)'' messages while cycling an LED with increasing/decreasing gpioPWM() values. As always, any help will be greatly ...
0
votes
3answers
235 views

Raspberry Pi Random Turns Off

So, I was doing a project with PWM (Pulse-width modulation) but something unsual happens, my raspberry pi turns off. I am using a RPi model 2B, and my circuit looks as follows simulate this circuit &...
1
vote
2answers
458 views

Testing my low frequency generator

I have my pi hooked up to a shaking device, and I'm looking to drive it at relatively low frequencies. My code looks like this: # Import the necessary header modules import RPi.GPIO as GPIO from time ...
2
votes
1answer
3k views

How to connect speakers onRaspberry Pi WH through PWM?

Let's say I am trying to embed a Pi WH in my motorcycle helmet. I need thin speakers just by the ear to hear sounds (so, I don't need them to be too loud). * by the way, piezo speakers won't do it ...
0
votes
1answer
513 views

Speeding up updating of GPIO pins

I have a program where each step, two GPIO pins have their duty cycle updated (I'm using pigpio). I'm running the program for millions of steps (think 50 to 100 million) and running the PWM outputs ...
1
vote
1answer
225 views

Trying to drive monitor backlight with gpio

Project: I am making a Pi powered photo frame with google photos integration. Object: I have added a pir sensor for auto screen off when no activity is detected and now i am looking to control ...
1
vote
1answer
3k views

RasPi3 and L298n PWM Speed Control

I have got all motors running correctly on the L298n. I want to set up speed control with them also. According to this tutorial, to do that I attach a PWM GPIO to the Ena on the L298n. They also are ...
0
votes
0answers
703 views

Controlling 30 LEDs with 2 PCA9685 boards - need to increase performance

I have a Raspberry Pi 3 and two Adafruit PCA9685 interfaces with which I am trying to control 30 white LEDs. Currently, I am using Python and Adafruit's module, this works fine, however, with the ...
1
vote
1answer
958 views

Python Chiptunes with PWM

I'm building a super barebones game console with a rasPi zero. I'm trying to get it to play some rudimentary music - I'd like to be able to write little tunes programatically (eventually have the ...
-1
votes
1answer
367 views

convert py file for RPIO to RPi.GPIO [closed]

According to Joan's instruction. First, git clone https://github.com/metachris/RPIO.git cd RPIO sudo python setup.py install sudo python3 setup.py install and sudo python3 jjy.py I made a jjy ...
1
vote
2answers
364 views

Send PWM signal from Raspberry Pi 3 BEFORE boot

I am using my raspberry pi 3 to run some services. When someone powers on the Raspberry I want to use RGB LEDs to indicate the status instead of using a LCD screen to output messages. The LEDs I plan ...
0
votes
1answer
654 views

SG90 servo is vibrating and heating when I try to control it using Raspberry pi 3

I brought a new SG90 servo and I tried to control it using my Raspberry Pi's pin 17 writing the following code on the terminal's python >>>import RPi.GPIO as GPIO >>>import time &...
-1
votes
1answer
2k views

Hardware PWM for Python 3.5 or higher?

I am developing a camera tracker to follow objects identified via OpenCV in a dedicated environment on mt Pi3. Currently the two SG90 servos are controlled by software PWM using RPi.GPIO - but the ...
0
votes
1answer
1k views

Best settings to drive a DC 24V motor with PWM [closed]

I'm driving a 24V motor like this using this motor driver connected to a RPi B+. I'm controlling it with Python and PWM with the following snippet: import RPi.GPIO as GPIO from time import sleep ...
2
votes
0answers
304 views

Using Hardware pwm as event timer?

in modern PC based Linux Machines it is possible to use hpet and realtime processes to get a reasonable good realtime performance (+-10us response time) While Raspberry Pi Hardware does not have a ...
2
votes
2answers
219 views

L293D to send data to a NeoPixel LED strip?

Does a L293D return the same signal on the output as it gets on the input? Or does it change a pwm signal to a rather constant voltage?
2
votes
0answers
349 views

Multiple servo motors with serial commands

I am trying to control multiple servo motors with a Raspberry Pi. I am using a USB to TTL cable for this. I am currently sending following serial commands for the movement. --> gpio -g mode 18 pwm --...
1
vote
2answers
1k views

Android Things: Any way to PWM on GPIO 20?

I'm playing with a motor board, a PWR.A52.A, that is mapping the ENA and ENB of its L298P to the BCM13 and BCM20. The problem is that Android Things is mapping the PWM to BCM13 and BCM18. I don't ...
1
vote
0answers
6k views

PWM with wiringPi library and C in order to blink an LED at a given frequency

I am working with the wiringPi library with C on a Raspberry Pi 3 Model B and attempting to understand and develop a model so that I can predict the blinking behavior of an LED connected to GPIO #18, ...
3
votes
3answers
2k views

Motor running slow using PWM

I'm new to PWM. This is my motor and controller. When I have the jumper in (ENA pins: I assume this gives the PWM pin the full 5V, as that is what the controller board runs on). My 6V 47 RPM motor ...
0
votes
1answer
229 views

Trouble using Pi's GPIO pin PWM to control ESC powered by separate battery

Can I use my Raspberry Pi to provide the PWM controlling my ESC, but have the ESC powered by a separate battery? The ESC I'm using is "A1S 3A Blheli 1S Super Mini Brushless ESC". It's awesome. And it ...
0
votes
1answer
587 views

"NameError: name 'L_R' is not defined" using GPIO.PWM inside a Class

I'm trying to create a class to define various led status using 3 leds. For some status only I need to use GPIO.output method, but in other cases I want to use GPIO.PWM method to create a blink effect ...
0
votes
1answer
384 views

How to use the DMA-DREQ/PANIC threshold of the hardware-PWM

I'm using the hardware PWM that is described on page 138 of the BCM2835-ARM-Peripherals document. The description of the DMAC-register (page 145) indicates that one can set the FIFO-threshold at ...
1
vote
0answers
324 views

Segmentation fault using PWM with RPi.GPIO?

I have some simple code that plays tones on a piezo buzzer. I thought it would make sense to use the PWM support in RPi.GPIO rather than rolling my own; my resulting code looks like this: def ...
0
votes
2answers
358 views

How would I control multiple solenoid locks?

I would like to control 16 separate solenoid locks using PWM (It is not imperative that the lock is 12V, it could be 6V for example). The PWM source is this 16-channel servo driver from Adafuit. Is ...
2
votes
1answer
1k views

Gpio PWM make interference with Audio jack output

I've connect a servo motor to raspberry. I have too an speaker connect via audio jack 3.5 mm. When I use gpio pwm it produces interference with speaker and it begins to make annoying noise. When I ...
3
votes
1answer
3k views

My servo jitters sometimes

I'm trying to build a toy model of self-driving car for my FYP. I have a RPi3 B+ Model with a custom 3D printed chassis which uses a futaba s3003 servo for steering front wheels. Servo is currently ...
1
vote
2answers
360 views

Updating to Raspbian 9 leading to errors using PWM (wiringPi)

A few days ago I updated my Raspberry Pi (Rev. 3) to the new Raspbian 9 (based on Debian "Stretch"). Everything went fine but when I tested some of my own tools I recognized a strange behaviour ...
0
votes
1answer
303 views

Using pwm to send packets

does anyone one know if it's possible to use the Raspberry pi to send packets via pwm? I want to interface the raspberry pi with some escs(electric speed controllers). These escs use Dshot (https://...
0
votes
2answers
1k views

Controlling DC motor with PWM in Processing

I'm trying to control DC motors with L298N motor driver. I'm using Raspberry Pi 3B and java GUI called Processing. I can't find PWM libraries for software control or use hardware PWM because I need ...
0
votes
3answers
12k views

How do I do a basic MOSFET switch with Pi?

I have my GPIOs doing PWM with pi-blaster. Now I just need to figure out the wiring. I checked over electrical engineering, and found this question: https://electronics.stackexchange.com/questions/...
1
vote
2answers
1k views

cannot control pwm through c program by wiringpi

I am trying to control frequency and duty cycle through c-program based on wiringPi library. Here is the code: #include <wiringPi.h> #include <stdio.h> #include <stdlib.h> #include ...
0
votes
1answer
285 views

Error: GPIO #num# is not enabled for pi-blaster

I currently have a project where I need to be able to use 12 GPIOs to control lights. I'm using pi-blaster for my PWM needs, and it works great where it works, but some GPIOs it throws no error when ...
1
vote
0answers
323 views

Rpi python GPIO PWM Controlling Digital Servo JX 5521MG Problem

I ordered a digital servo JX 5521MG to use with my Pi but when I use the code below the servo does not move but there is a slight tick or twitch inside. gpio pwm-ms gpio pwmc 192 gpio pwmr 2000 ...