How does one do a print screen in Raspian? I used the scrot command to no avail. Also, how do I enlarge the capture to focus it better? Any help is appriciated.
I think you can use VNC to view the interface of your Raspberry Pi to your desktop/laptop and then take a print screen from there. Here is the documentation of VNC from the official site:
https://www.raspberrypi.org/documentation/remote-access/vnc/
Related
I bought a new micro:bit v2 board, and want to add it to Scratch as an extension. I followed the 2 steps from https://scratch.mit.edu/microbit. The step 1 is ok, the led lights of my micro:bit board is flashing 5 characters "zepiv", but the step 2 failed.
The scratch link is running, and the bluetooth is enabled.
The os version is macOS Big sur 11.4(Mac mini late 2014), the bluetooth LMP version is 4.0(0x6).
The weird thing is that the board isn't visible to my Mac, but it is to my Android cell phone.
Is this a problem with my computer? Could anyone help me? Thanks in advance.
Good question, I had a lot of trouble with the same issue when connecting my LEGO MINDSTORMS EV3© to scratch. If you want to connect a device easily a good idea is to have it paired via Bluetooth already. To pair it with a mac:
Open the settings app
Select Bluetooth
Switch your micro:bit into pairing mode:
Hold down buttons A and B on the front of your micro:bit together. The front is the side with two buttons and the LED display. Keep the two buttons held down. Don’t let go of them yet!
While still holding down buttons A and B, press and then release the reset button on the back of the micro:bit. Keep holding down buttons A and B.
You should see “PAIRING MODE!” start to scroll across the micro:bit display. When you see this message start to appear you can release buttons A and B.
Eventually you’ll see a strange pattern on your micro:bit display. This is like your micro:bit’s signature. Other people’s micro:bits will probably display a different pattern.
(I found these instructions at this website)
In the Bluetooth menu, look for your micro:bit device and select Pair
After the device has paired, go back to scratch with scratch link activated, and attempt to connect to the device again.
This worked for me when I connected my EV3 device and I hope it helps you.
I am a software engineer working on a microcontroller system for a side project. The microcontroller I am using is the SparkFun ProMicro (based on the RP2040 board). I am trying to flash the board so that I can write data to the onboard flash memory.
All of the tutorials I have found online suggest starting in boot mode, dragging and dropping the UF2 file, and done!
When I do this, the microcontroller ejects from my computer. Is that meant to happen? It just reboots then doesn't reboot in bootloader?
Once I got MicroPython installed I moved on to writing and flashing code to the board.
I am using the Thonny IDE which identified the correct board (albeit the PICO), then saved the following file as main.py (taken from RPI foundation). It prints toggle, and I believe the output shows that it is being printed from the board, but the light on the board isn't blinking. (code and output below)
I considered that the pinout could be different from this board and the PICO, but some research shows they both use Pin 25 for the LED control.
All this leads me to believe I am on the right path, but I think I am missing something that is taken for granted in the tutorials. My end goal is to write arbitrary text data to flash storage, but I understand it can only take about 8000-10,000 writes before it becomes unreliable, so I want to test that I can write working code before I use some of those.
Is there something I am missing, or am I not thinking about this in the right way?
When I do this, the microcontroller ejects from my computer. Is that meant to happen? It just reboots then doesn't reboot in bootloader?
Yep.
but the light on the board isn't blinking.
Maybe your LED is busted, cause your code is right.
My end goal is to write arbitrary text data to flash storage
That's a terrible idea, unless you just like burning up boards for no good reason. Get an SD Card reader or concoct one out of a solution like this one, and use this sdcard library that will even mount your card, and add it to the syspath. Then you can essentially write all the arbitrary text data you like without burning up your RP2040.
Blinking this LED was harder than I expected. I ended up finding this sample code from AdaFruit and using the commented out neopixel code. The... bright side was that there was way more control over this led that I had realized.
Dont forget you have to add the neopixel.mpy from the bundle to your board.
With the RPi Pico W, you can now identify the led pin with "LED" instead of pin 25 (or another pin). This change is due to pin 25 being used for the Wifi chip on the Pico W. This works on Pico W as below
from machine import Pin
import time
led = Pin("LED", Pin.OUT)
while True:
led.toggle()
time.sleep(0.5)
I have verified this working on a RPi Pico W with MicroPython - using the unstable python version - rp2-pico-w-20220719-unstable-v1.19.1-181-gc947c2529.uf2.
I believe this is intended to become the standard way to access an on board led, since the port can be changed for different boards without changing source code.
That's not a simple LED connected to pin 25 on the Pro Micro RP2040 - it's a WS2812 RGB LED, sometimes called a NeoPixel. There's a one-wire protocol to drive these devices.
MicroPython has support for NeoPixel's built-in:
from machine import Pin
from neopixel import NeoPixel
pin = Pin(25, Pin.OUT) # set Pin 25 to output to drive a NeoPixel
np = NeoPixel(pin, 1) # create NeoPixel driver on Pin 25 for a single pixel
np[0] = (255, 0, 0) # set the first pixel to red (R, G, B)
np.write()
See the rp2 Quickref for more details.
So I saw this video:
https://www.youtube.com/watch?v=4ElZec033vQ
https://www.youtube.com/watch?v=ClFSUXebY7Q
This video does it without the whole circuitry.
And I wanted to do something similar, but more controlled.
I want to be able to use a raspberry pi to operate a phone screen (like your finger does) and be able to code how long between turning the touch on and off. I'm using Python. I have a penny on my screen and the wire touching it. The wire is connected to GPIO 17. When I first boot up the pi, touching the wire to the penny does nothing. I have a program that registers GPIO 17 as an output and turns it on and off. When connected to an LED, it does just that. However, it constantly activates the phone without ever turning off, even when I stop the program. I tried cleanup(), which does work in a weird way. If I hold it to the penny, cleanup() doesn't do anything and the wire continues to activate the phone. But if cleanup() has already happened and I briefly break the connection, then it no longer activates the phone.
How can I code a wire to put out a signal and turn off said signal when I want?
The guy in the video is using C and an arduino, so basically I want to convert that to a Raspberry Pi with Python.
use the Gpiozero library .... there look for Led
import gpiozero
import time
coin=gpiozero.LED("GPIO17")
while(1):
coin.on()
time.sleep(1)
coin.off()
this code should control GPIO17 but you can choose another. Just try
I think that my question is a little bit dumb but i am really stuck in this problem.
I have an embedded SAMA5D27-SOM1-EK1 board which i build Linux OS image version 4.14 with YOCTO project.
Now i want to control a RBG LED using a push BUTTON existing both on the board.
They asked me to check for GPIO drivers if they are existing in my Linux Image, I don't know how to check, then to make the LED Lights when I push the Button.
For the moment i have only the PINS of the Led and the Button.
I don't know what i must do now.
Thank you for your help!
I am using a 7" TFT LCD Display (1024x600) with the Raspberry Pi 3 and I can not make it work with that screen resolution. It looks like it is zoomed in.
I know that there are a bunch of topics about this issue in and out stackoverflow, and I have tried to edit the config.txt as much as I could, never getting different results. (BTW: I got it working with Raspian really easily editing the config.txt, but it does not work for android for some reason).
I used this Android image, and this is how my config.txt looks like:
hdmi_force_hotplug=1
hdmi_drive=2
hdmi_group=2
hdmi_mode=87
hdmi_cvt 1024 600 60
Framebuffer_width=1024
Framebuffer_height=600
disable_overscan=1
config_hdmi_boost=5
kernel=zImage
device_tree=bcm2710-rpi-3-b.dtb
dtparam=audio=on
dtparam=i2c1=on
dtparam=i2c_arm=on
dtoverlay=vc4-kms-v3d,cma-256
initramfs ramdisk.img 0x01f00000
mask_gpu_interrupt0=0x400
avoid_warnings=2
gpu_mem=256
enable_uart=1
I would really appreciate some insight on this.
PS: I tried different resolutions with the hdmi_group and hdmi_mode, according to this RPi article, but the image remains the same.
So I finally got it working by trial and error, and I posted the answer in the RaspberryPi Stackexchange site as suggested. Case closed for now.
I had the same 'zoomed in' effect using Android Studio (React-Native) with an 800*480 HDMI screen (Waveshare 5-inch). When I used Dimensions, within the app, to get the screen size, it returned approx 530 * 300, which had the additional effect of changing the bucket size for images being copied over from the assets folder. My solution, found after some considerable time, was from Dokter_Bibber at this link. It did not give me precisely the same display as my 800*480 Android-Studio-emulator that I was using to develop my page, but pleasingly close.
Quoting from the link:
Start Console window and type :
adb shell wm size 800x480
---AND (186.59 ppi calculated here : https://www.sven.de/dpi/ 4)
adb shell wm density 187
THEN (reboot the device)
adb reboot