Hot answers tagged

17 votes

What does "dtoverlay=dwc2" REALLY do?

The answer to your question title has been hard to word better than gregeric explained: dwc_otg is the driver that has been heavily patched to squeeze most performance & function in host mode on ...
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11 votes

Raspbian Stretch: Getting Error: missing `server' JVM at `/usr/lib/jvm/java-8-openjdk-armhf/jre/lib/arm/server/libjvm.so'

I actually fixed this error going step by step, apt seems to have a bug in the way it handles ca-certificates-java and openjdk-8-jre-headless on raspbian. So I did : sudo apt-get remove openjdk-8-...
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10 votes

Python serial permission issue

@LiWi's answer will work temporarily, but the permission change will be lost once the device is removed or the server rebooted. A permanent solution is to add your user to the dialout group, which ...
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7 votes

Level of Hackability of raspberry pi

To update Krzysztof's great answer, Broadcom finally publicly released some code, licensed as 3-Clause BSD, to aid the making of an open source GPU driver. The "rpi-open-firmware" effort to replace ...
  • 171
7 votes

Use Arduino code on raspberry pi?

There is an Open Source project underway at: https://github.com/me-no-dev/RasPiArduino This basically allows one to use the Arduino IDE in conjunction with a cross compiler that generates executable ...
  • 1,774
7 votes
Accepted

How to use Arduino devices with Raspberry Pi?

"Arduino devices" are really just general purpose devices that operate on 5V logic and can be connected to a bus style supported on an Arduino, such as UART, SPI, or I2C, none of which originated with ...
  • 56.9k
6 votes

How to get Data from Rasperry to Arduino?

You can connect the Arduino to the Raspberry Pi with an USB cable. That gives you a serial connection. On the Raspberry side, you can use a library like pyserial. On the Arduino side, you can read ...
  • 161
5 votes
Accepted

Soil moisture sensor compatibility

The link you give is to the soil sensor which is not an Arduino. Did you mean to ask whether you could use the soil sensor with the Pi? Yes you can but to get analogue results you'd need to add an ...
  • 68.3k
5 votes

Are the SPI pins 5V tolerant?

ALL the Pi GPIO are 3V3. NONE of them are tolerant of voltages outside the range 0 to 3.3V. EDITED TO ADD: The only pin which feeds into the Pi will be that connected to MISO (Master In Slave Out). ...
  • 68.3k
5 votes
Accepted

I2C using wiringPi or IOCTL in C, more than 2 bytes

I'm wondering, may understand that Raspberry Pi's I2C is in fact the SMBus version of I2C ? I don't think it is limited in that sense but that is the normative way to use it. There is no such ...
  • 56.9k
5 votes
Accepted

Detecting Pi has been unplugged instead of shutdown

If you want the Pi to be able to tell you (via email notification or whatever) that it was not shut down properly the last time it was active, a simple solution is to arrange for a simple script that (...
  • 646
4 votes
Accepted

Major trouble with nRF24L01+ controllers and the RF24 library

I finally figured it out. What happened was that when I first got the modules I accidentally hooked them both up to a 5V rail instead of the recommended 3.3V, or at least this is my best guess as to ...
4 votes

Meaning of cmd param in write_i2c_block_data

When you issue a block write/read from the Pi with: bus.write_i2c_block_data(i2c_address, register, list of bytes) Example: bus.write_i2c_block_data(80, 0, [49, 50, 51]) or bus.read_i2c_block_data(...
4 votes
Accepted

Voice recognition on arduino or raspberry pi?

I'd go so far to say that the computational power of an arduino would be quite a limit to voice recognition. Bitvoicer for example uses the arduino to sample the speech but not to process and ...
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4 votes
Accepted

How to serially communicate between raspberryPi and arduino using usb to serial converter?

You may be finding the UART(or USART) communication, which is what Arduino RT/TX pins and some of RPi GPIO pins used for. USB ports uses 5V and UART pins are for 3.3V, thus you may need additional 5V-...
  • 156
4 votes

communicate with arduino over serial

You need to do a few things before being able to use /dev/ttyAMA0 Add your user (that will use ttyAMA0) to the dialout group: sudo usermod -a -G dialout pi (pi is the user here) Disable linux ...
  • 161
4 votes

Shutdown Pi via USB stick

I see two ways of doing this: 1. UUID Based You could write a very simple script, possibly in Python, to check for a specific UUID to be plugged into the Pi. The script would then shutdown the Pi. ...
  • 6,275
4 votes
Accepted

Send data from Python to Arduino through serial port

I do this all the time. Two-way communications works just fine. Yes I keep my ports open continuously. UNLESS I am running the IDE. The IDE requires that I not have any other programs trying to ...
  • 2,228
4 votes
Accepted

Digital data reading using GPIO

I am surprised your search did not find any solutions. How do you think computers communicate? The simplest solution is to use a serial link. For Arduino to Pi connect the Arduino's TX pin to the ...
  • 68.3k
4 votes

Connecting 2 Raspberry Pi together

There are a variety of options for connecting two Raspberry Pis together. The easiest, if both Raspberry Pis are already on the same wireless network, is not to bother with a cable and just ...
  • 646
4 votes
Accepted

Using Arduino kits with Raspberry Pi 3

There are a few significant differences between a Pi and an Arduino hardware interface wise: The Arduino uses 5V logic whereas the Pi uses 3.3V logic. Some sensors can be used either way, powered by ...
  • 56.9k
4 votes

Failed to connect: org.bluez.Error.NotAvailable - Error

You do not need to connect with Bluetoothctl. With Bluetoothctl, use exactly most commands as you show; then after pair, leave this window but not close. Open new terminal and use rfcomm bind rfcomm0 ...
  • 41
4 votes
Accepted

Connect to Raspberry Pi Over the Air Without Internet

Wow... Interesting project! You're lucky to be involved in something like this as it's the best learning experience. Anyway - to your question: The problem of communicating with oceanic sensors has ...
  • 19.3k
4 votes
Accepted

Arduino slave initiating an I2C transmission to Raspberry Pi master

This is not how I2C is specified and supposed to work: The aforementioned reference design is a bus with a clock (SCL) and data (SDA) lines with 7-bit addressing. The bus has two roles for nodes: ...
  • 15.6k
4 votes
Accepted

How to send and read a string from Raspberry pi to Arduino via serial interface?

Finally I was able to find a solution. I used the example 2 from this post posted in Arduino forum https://forum.arduino.cc/index.php?topic=396450.0. I have edited python code also. Arduino code // ...
  • 315
4 votes
Accepted

Moved from main Stack Overflow: Udev Rules Not working with Rasberry Pi - Teensy connection

Traditional unix preassigned device numbers for every possible device at the time the kernel was compiled, and a script would then probe the system and create device files for devices that actually ...
  • 874
4 votes
Accepted

Can a program be stored in flash memory on raspberry pi and run without a monitor and internet connection like on an Arduino?

The Pi just needs a boot medium and some storage. This is commonly an inserted SD card but for recent model Pis this could be a USB stick instead. An attached screen and keyboard (and internet) is a ...
  • 68.3k
3 votes
Accepted

Use interrupts in i2C between Ardiono and Raspberry Pi

Do not use I2C. The standard Raspberry Pi Linux I2C driver can only act as a master device. It can not deal with unsolicited I2C messages. Use the serial link instead. On the Pi end that is /dev/...
  • 68.3k
3 votes

Raspberry Pi to Arduino (Leonardo) avoiding latency

Between a Raspberry Pi and an Arduino, using UART is the best option. I know because this is my 3rd project doing so. (And also USB is impossible) You should run the UART at 1000000 baud. Default ...
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