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5 votes
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Creating jumper leads from ethernet cables - connect multiple components

I do this all the time. Ethernet (Cat5) cable is twisted pair, which provides you with cross-talk protection. Note that the longest run I've used is about 36", so you may have to do testing to ensure ...
stevieb's user avatar
  • 1,456
5 votes

Creating jumper leads from ethernet cables - connect multiple components

Lots of folks do that. You may need to add some small capacitors on long cable runs to reduce and RF interference that a long unshielded cable can pick up.
Dougie's user avatar
  • 5,321
5 votes

How to connect a graphic card to Raspberry pi?

I originally flagged this as being, possibly seriously, Off-Topic but technically there is a further method that make it possible to connect a graphics card to the RPi and have the latter generate ...
SlySven's user avatar
  • 3,621
4 votes

GPIO - RuntimeWarning: This channel already in use, continuing anyway

I found the completed solution for your issue: RPi.GPIO basics 3 – How to Exit GPIO programs cleanly, avoid warnings and protect your Pi I see this is the best way to other answers. Basically you ...
4 votes

Will 3.3v gpio work for a fan without hurting the pi?

The short answer is yes. The long answer is yes, but... 3.3VDC is enough to run a low speed fan provided its designed for 3.3VDC. I wouldn't try anything larger than a 40mm fan like this one, and ...
Sandor Dosa's user avatar
4 votes
Accepted

Use GPIO to trigger button press in software

Connect a relay or an NPN transistor to bridge the two sides of your switch and program the Pi to set the base of the transistor or relay to high for about half a second - as if a button were being ...
Mohammad Ali's user avatar
  • 2,383
3 votes
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pigpiod callback is exiting my code

As the code is written in your question, it is creating an unlimited number of callbacks. Eventually the system will fall over because of a lack of resources. Also a pigpio callback receives a set ...
joan's user avatar
  • 71.1k
3 votes

Is there any way to control Raspberry Pi GPIO pins without Webiopi?

pigpio has a Python module which can control the GPIO of a networked Pi from a Windows, Mac, or Linux PC.
joan's user avatar
  • 71.1k
3 votes
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Get export state of GPIO pin (pi-gpio)

If GPIO X has been exported then the directory /sys/class/gpio/gpioX will exist. E.g. if GPIO 4 has been exported $ ls /sys/class/gpio export gpio4 gpiochip0 gpiochip100 unexport If it has been ...
joan's user avatar
  • 71.1k
2 votes
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Is there any way to control Raspberry Pi GPIO pins without Webiopi?

The recent GPIO Zero release (1.4) includes several new chapters on remote GPIO: Configuring Remote GPIO Remote GPIO Recipes I should add that this is achieved via Joan's excellent pigpio package, ...
Dave Jones's user avatar
  • 3,978
2 votes

Using the ds18b20, why are you limited on pins you can use? GPIO4 only one that seems to work

The DS18B20 is a (Dallas) 1-wire bus temperature sensor. It uses one wire for control and data. Early versions of Pi software only allowed for the 1-wire bus to be started on GPIO4. You are looking ...
joan's user avatar
  • 71.1k
2 votes
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Can I use a transistor as a relay with the Pi?

I would not recommend calling a transistor a relay. While they would do essentially the same thing in this particular case (switch an electrical signal) they're technically different with respect to ...
Ghanima's user avatar
  • 15.9k
2 votes
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How to work several GPIO pins with shell script

By default the wiringPi's gpio utility uses wiringPi numbering for the GPIO. You seem to want to use physical pin numbers. https://pinout.xyz/ Pin 7 is Broadcom GPIO 4 (wiringPi number 7). Pin 12 ...
joan's user avatar
  • 71.1k
1 vote
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why GPIO does not work when executed from python shell but works from script

You are not setting the GPIO level. The LED will go on when you execute GPIO.output(24,GPIO.HIGH) The LED will go off when you execute GPIO.output(24,GPIO.LOW)
joan's user avatar
  • 71.1k
1 vote

How to simultaneously control over 200 GPIO pins while maintaining timing accuracy

I2C is fundamentally slow, as Milliways has explained. There are SPI IO expanders which can achieve much better timing. E.g. here a chip from DIGI which offers 32 IO pins which can be configured as ...
Dmitry Grigoryev's user avatar
1 vote

ERROR: PWM Generation using pigpio C library

pigpio supports two types of PWM. DMA timed PwM on GPIO 0-31. This has a limited number of frequencies and duty cycle resolution. See gpioSetPWMfrequency for the permitted frequencies. I am not ...
joan's user avatar
  • 71.1k
1 vote

Flow meter circuit and low pulse count

I'm going to guess what your circuit really looks like because the schematic does not look reasonable to me. I'm guessing that you have used two resistors as a voltage divider to reduce the maximum ...
Elliot Alderson's user avatar
1 vote
Accepted

Strange return from pigpio i2c_read_device

That is how Python displays a bytearray. If the character is a printable character it is shown as such (the '}') in your example. If the character is not printable it is displayed in escaped format, ...
joan's user avatar
  • 71.1k
1 vote

Will 3.3v gpio work for a fan without hurting the pi?

You can safely run a 5 V fan from Pi 3.3 V standard supply (Pin 1). Using a Geek Pi 4-level Raspberry Pi case that comes with a 120 mm LED fan. Supplied at 5v the fan is a bit loud. At 3.3 V the fan ...
BodhiOne's user avatar
1 vote

Will 3.3v gpio work for a fan without hurting the pi?

You can draw up to 800 mA from the Pi 3.3V. See Raspberry Pi Power Limitations Why you would want to run a fan (3.3V or other) on the Pi is a mystery.
Milliways's user avatar
  • 60.3k

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