I have a raspberry pi 3 model B and a Kano LED light ring
my kid stopped using the raspberry pi and i repurposed it to make a pihole, it doesn't have the KanoOS anymore and just has the regular raspbian OS running my DNS server.
The lights on the LED were always on really bright (white only), and I wanted to learn how to change the colors. I used the code below, which when I ran the program it turned the lights off but won't turn them back on. If I restart the pi, it will turn them back on. If I rerun the code it turns them all off again. Anyone have any ideas on how to trouble shoot this?
import board
import neopixel
pixels = neopixel.NeoPixel(board.D18, 10, brightness=0.3, auto_write=False)
pixels[0] = (255, 0 , 0)
pixels.show()
Thanks again for any help.
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
So I'm using an STM32F103C8T6 board and it was working fine a few days ago but then tried to load a code with keil vision compiler these days and it showed this message STLINK Error(DEV_TARGET_HELD_UNDER_RESET).
After that using the STM32CubeProgrammer also shows the same problem, only connects with the "hot plug" mode
as you can see here
Its cleary a reset error, but I really dont know how it happened and don't find much resources on the internet with this problem and now I can't download any code in my stm32f103 board it shows
this message
After researching on the internet found it might be soldering problem, but I dont think its the case, i'm only using the microcontroller, not any bread board circuit, and it was perfectly fine days ago. All my write and read protections checkboxes are unchecked in the STM32CubeProgrammer sections too.
I guy on the stcommunity just said "he went through all CPU pins and the board started working." but is it a problem with the pin reset? in the STM32F103C8T6 board it has a reset buton but how can a search a problem in it?
Ok, this is what I did and now it seems to be working (I'll try to be as descriptive as I can, so you or anyone who's got stuck into this can compare):
I'm using STM32CubeProgrammer v2.6.0 under Ubuntu. The parameters to connect to the target are:
Port: SWD
Freq: 4000 kHz
Mode: Normal
Access Port: 0
Reset Mode: Software reset
Shared: Disabled
I'm using an STM32f4 Discovery as a programmer, to achieve this the jumpers should be disconnected. It is supposed that SB11 jumper (under the board) should be unsoldered too, but as you will see I'm not using the reset line on SWD. The target (STM32F103C8T6) is powered independently (+3.3V).
The connections between the target and programmer are the following:
Prog pin1 (VDD) --> NC
Prog pin2 (SWD Clock) --> PA14 (Pin#37)
Prog pin3 (GND) --> VSS (Pins# 23,35,47 and 9 if common digital analog ground)
Prog pin4 (SWD I/O) --> PA13 (Pin#34)
Prog pin5 (NSRT) --> NC
Prog pin6 (SWO) --> NC
I have access to the target's NSRT (Pin#7) through a push-button (this is important).
Once all this is ready, what I did was to press and hold the reset button, then press the connect button in STM32CubeProgrammer (without releasing the reset), and wait just two seconds, then release the reset. After this process, the target was connected and I was able to program it normally.
The program will not run immediately, you need to push and release the reset button again.
Juliane - the (DEV_TARGET_HELD_UNDER_RESET) message means that something is holding nrst to ground. You can't do much apart from 'hot plug' when in this mode. If you have a reset button then it may have failed in a connected position which will pull NRST to ground defeating the internall pullup.
Can you check the resistance across you reset button in down and up position. I suspect it is 0 ohms (or at least lower than internall pullup resistor).
If you don't have a reset button then check to see what circuitry is around NRST and try to work out why its pulling to ground.
First you need to clear the existing flash memory
it can be done with ST Link Utility or STM32CubeProgrammer
Hold down Reset button while clicking 'connect' on STM-Prog, then navigate to 'Erasing & Programming' and click 'Full chip Erase'
or
while holding reset click Full Chip Erase on ST Link Utility
After the chip is clean try setting the Debug to Serial wire
this will allow to flash new code to the board multiple times without having to clear the flash memory or holding reset before upload
in Pinout & Configuration
or in stm32f1xx_hal_msp.c
"DEV_TARGET_HELD_UNDER_RESET" can also have a hardware reason. I experienced this by accident with a PCB where I mixed up some numbers and ended up with a 10 Ohm resistor instead of a 10k Ohm resistor between 3V3 and the NRST pin on a G431RB. Usually I use a 10k resistor to connect the Reset Switch to the NRST Pin.
The end of the story was, that I was not able to connect to the MCU, the error message was "DEV_TARGET_HELD_UNDER_RESET" and I had some hard time to figure out what it was. Once I replaced the 10 Ohm Resistor with the correct value (10 kOhm) anything worked fine.
not strictly a programming question but found no other solutions on the web. Using the Pi i have followed the diagram below to control two motors in an old rc tank chassis.
diagram
Ive gotten all the hardware correct, i.e. H-Bridge etc but what happens is the motor connected to pins 7&11 (4 and 17 for BCM mode) just starts spinning.
My question is are any of these pins set to autimatically transmit a signal on power up or is this an OS issue. Any help would be much appreciated thx :).