5
votes
Accepted
PWM stop respond after hundreds of start/stop
I am fairly sure it is a bug in the RPi.GPIO module.
Look through https://sourceforge.net/p/raspberry-gpio-python/tickets/
As a workaround I suggest you do not use the start() and stop() methods in ...
- 71.6k
5
votes
Control a 12V dc fan via PWM and a level shifter
Since everything is working now I want to post a summary of how I am controlling a 12V fan with my Pi.
My Hardware for this is:
1x KeeYees 4-channel IIC I2C level shifter from 3.3V to 5V
1x Artic F9 ...
- 103
4
votes
PWM input in Raspberry Pi
I can do fairly accurate pulse width measurement using the piGpio C library:
http://abyz.me.uk/rpi/pigpio/index.html
This library enables you to install a callback function that will trigger on any ...
- 41
4
votes
Controlling servo with Raspberry Pi but it doesn't stand still
You are using the wrong tool for the job.
Servos require accurately timed pulses. The RPi.GPIO module uses software timing which leads to all sorts of timing jitter, which leads to a twitching servo,...
- 71.6k
4
votes
Raspberry pi PWM stability
You need to use hardware timed pulses for servos.
Software timed pulses will lead to jitter and a shorter servo lifetime.
Try pigpio, servoblaster, RPIO.GPIO, or similar which use hardware timed ...
- 71.6k
4
votes
Android Things: How many PWM pins on Pi 3 Model B?
All Pi models have identical GPIO, even though the pinout varies between models. PWM can be assigned to different pins, but there are still only 2 channels. See http://www.panu.it/raspberry/ for ...
- 61.4k
4
votes
PWM on 5V GPIO pin
If you take a look at the spec sheet for that fan (the fan you linked is a 4-pin varient):
You'll see that the PWM signal pin must be 5V. Now why it works with 3.3V (GPIO voltage) is likely because ...
- 6,365
4
votes
What is the relationship between angle and servo motor duty cycle? How do I implement this?
Servos are controlled by pulse width, the pulse width determines the horn angle.
A typical servo responds to pulse widths in the range 1000 to 2000 µs.
A pulse width of 1500 µs moves the servo to ...
- 71.6k
4
votes
Accepted
Can unstable PWM timing be corrected?
pigpio supports DMA timed PWM on GPIO 0-31. This has restricted frequencies and resolution.
http://abyz.me.uk/rpi/pigpio/python.html#set_PWM_frequency
pigpio also drives hardware PWM on GPIO 12, 13, ...
- 71.6k
4
votes
Accepted
Using GPIO PWM with sysfs
To use pwm, you need to use the pwm interface at /sys/class/pwm, not the gpio interface.
Here is the relevant documentation. The startup would be something like export 1 > /sys/class/pwm/pwmchip0/0/...
- 906
4
votes
Using Hardware PWM in Raspberry Pi 4
The Pi has only two accessible hardware PWM channels. GPIO 12 and 18 share one setting, GPIO 13 and 19 the other. So if you set GPIO 12 to 15% dutycycle at 400Hz that will come out of GPIO 18 as ...
- 71.6k
4
votes
Disable automatic fan speed control of the Raspberry Pi 5 to control it manually
I also searched for a few days and didn't find what I was looking for.
So for me (with the official Raspbian) and without any modifications it actually works amazingly easy.
I use the official case ...
- 41
3
votes
Accepted
GPIO reset needed for Servo?
If you don't set the mode, it will not work. No, it is not hazardous.
No, you do not need to clean up GPIO after the script runs. Indeed, if you do so, the servo will not work properly.
- 71.6k
3
votes
which driver can control 4-5 motors, different types of sensors, speakers?
The most capable motor controller board that gets closest to what you require is called the 4tronix Picon Zero.
As you can see from the picture, it allows you to drive 2 DC motors (bottom right) and ...
- 4,489
3
votes
What is the pin number for PWM outputs on RPI3 model B?
There are two hardware PWM channels. Channel 0 is available on GPIO 12 and 18. Channel 1 is available on GPIO 13 and 19.
You can use the pigs hp command to set hardware PWM (requires the pigpio ...
- 71.6k
3
votes
Accepted
Android Things: How many PWM pins on Pi 3 Model B?
I suggest you put a hat on top of your raspberry pi. They communicate via I2C and multiply your PWM pins and you can stack them, there are already Java libraries popping out.
Yesterday, I ...
- 146
3
votes
How do I do a basic MOSFET switch with Pi?
Most MOSFETs will not work with the RPi at all; the ones that do will not work well. Here are the issues:
Most MOSFETs require gate-source voltages (Vgs) that exceed the 3.3V output the GPIO is able ...
- 22.8k
3
votes
Accepted
Send PWM signal from Raspberry Pi 3 BEFORE boot
PWM (Pulse Width Modulation) applies to digital as well as analogue signals.
Individually addressable LED strips, such as you want to use, are not controlled by PWM signals. They are controlled by ...
- 71.6k
3
votes
Testing my low frequency generator
Use hardware PWM. There are two channels on the Pi. One channel is available from GPIO 12 and/or 18, the other channel is available from GPIO 13 and/or 19.
pigpio and wiringPi both support hardware ...
- 71.6k
3
votes
LED pwm fading is flickering
The RPi.GPIO Python module uses software timing for PWM. Occasionally the software will be delayed leaving the LED on or off for longer than expected. This will be seen as flickering.
You could ...
- 71.6k
3
votes
Accepted
3 PWM pins for RGB LED
My pigpio provides hardware timed PWM on any of GPIO 0-31.
C, Python, and from the command line (pigs).
No need to waste money on additional hardware.
- 71.6k
3
votes
Turn a Raspberry Pi into a voltage tester
Question
Let me first summarize the OP's question.
He has a 220VAC water pump. He knows that a 555 IC can tell AC current on by blinking a LED. His question is how to let Rpi talk to 555 to find ...
- 4,787
3
votes
How can Rpi4B python UART talk to XY PWM Signal Generators?
Question
How can Rpi4B python UART talk to XY PWM Signal Generators?
Answer
Contents
(1) Introducing XY-LPWM, UART support version of XY-PWM
(2) Using Win10 RealTerm terminal emulator to ...
- 4,787
3
votes
Can I reliably control four ESC with a servo driver board?
pigpio will let you control ESCs from the Pi.
It uses hardware timed PWM.
Python: use set_servo_pulsewidth
C: use gpioServo
Command line: use pigs s
- 71.6k
3
votes
Accepted
PWM problem in a frequency less than 100Hz
I expect in reality the final state of the GPIO is pretty random. As you don't do a cleanup GPIO 17 will be left as an output. Its level will remain at whatever it was when the sleep elapses and RPi....
- 71.6k
3
votes
Accepted
raspberry pi fan don't start to spin without hand help!
If it's connected as you claim, then the fan is probably faulty.
There are things you could do to check, but you didn't say if you had a voltmeter or oscilloscope available. So - here is one check you ...
- 22.8k
3
votes
Accepted
Audio via PWM pins?
Default audio uses PWM (AFAIK pins 40,41).
It is POSSIBLE to enable PWM on header pins (which will disable headphone jack), and there are a few tutorials explaining this - mainly intended for those ...
- 61.4k
3
votes
Accepted
How can I use dtoverlay=pwm
I recently discovered some kernel documentation Pulse Width Modulation (PWM) interface
Like much kernel documentation this is inscrutable. It states This API controls both the PWM period/duty_cycle ...
- 61.4k
2
votes
Can't open pwm pin
You probably by now would have found answer. In case you are still looking for this, here is my answer:
I have used PWM mode in Raspberry pi without any problem. The only thing that is probably not ...
- 21
2
votes
3.5 mm jack starts to "hiss" after sound is played
I was able to get rid of the hiss entirely by adding audio_pwm_mode=2 to my /boot/config.txt. BTW: I also have a ground loop isolator between my audio jack and my amp.
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