I would like to control a WaveShare e-Ink display wirelessly. I have lots of experience working with this type of device over SPI using the GPIO boards and the WaveShare python libraries.

I'd like to see if I can do something similar using a wireless module.

I've read about XBee, ZigBee, looked at at least half a dozen different AdaFruit development boards, but I'm a little bit lost. Any suggestions as to modules that can provide some of this functionality would be greatly appreciated.

The WaveShare e-Ink display uses the following pinouts.

|Pin   | SPI                                                       | 
|------|-----------------------------------------------------------|
| VCC  | 3.3V                                                      |
| GND  | GND                                                       |
| DIN  | SPI MOSI                                                  |
| CLK  | SPI SCK                                                   |
| CS   | SPI Chip Select (low active)                              |
| DC   | Data/Command control pin (High for data, low for command) |
| RST  | External reset pin (low for reset)                        |
| BUSY | Busy state (low for busy)                                 |

I wanna record my screen and audio, Is It Possible? how to do that?
I use Raspberry Pi 4 Model B.

I still new, I hope you can help. thanks.

GOAL

A 3-Wire DHT 11 of unknown pedigree is to be connected to a Raspberry Pi:

SDA GPIO

The goal is to take "due diligence" and avoid frying an rPi. Thank you

RESOURCES

Ada Fruit's 4-pin DHT11 indicates 3-5 Power.

The "kookeye" tutorial shows 3.3V power & 3 direct wires between DHT11 and rPi.

QUESTIONS

1. If powered by 5V, will the DHT11 communicate at proper (3.3V?) voltage level?
2. If powered by 3.3V will the DHT11 communicate at the proper 3.3V voltage level?

On Raspberry pi, I want to use Raspbee as zigbee controller and SIM7600E-H 4G HAT as GPRS shield for network data

https://www.amazon.co.uk/Waveshare-4G-Raspberry-SIM7600E-H-Supports/dp/B07F1NSGQ8/ref=redir_mobile_desktop?_encoding=UTF8&*Version*=1&*entries*=0&th=1

https://www.amazon.co.uk/RaspBee-premium-ZigBee-Raspberry-Firmware/dp/B00E6300DO/ref=redir_mobile_desktop?_encoding=UTF8&%2AVersion%2A=1&%2Aentries%2A=0

How do I achieve that?

To enable zigbee controller I use the proprietary REST API coming from Dresden Elektronik and when i use raspbee alone with raspberry pi, it works perfect and I am able to detect the sensors. But with these all three, the zigbee controller does not work. I am not sure if I have connected the GPIO headers properly, but I see red led light glowing when I connect all these and power on. Please refer the image,

Previously the omxplayer is working fine, until I resized the boot partition (because I run out of sdcard and windows cannot read ext partition), and the omxplayer no longer plays anything. The system boots fine tho...

I have already tried recompiling the omxplayer from https://github.com/popcornmix/omxplayer, but it still same problem

For some files, it returned "have a nice day ;)". But when I tried test video (located at /opt/vc/src/hello_pi/hello_video/test.h264), it returned "Aborted"

Is there anything can I do except resize boot partition back or start with fresh image?

I have a PI 3b+ in a MIDI foot controller and part of the IO is a pair of expression pedal sockets. After, ahem, getting the tip and sleeve round the wrong way, they are working correctly now. But during testing I disconnected one while the system was powered up and it shorted out the PI, which is now dead. The circuit feeds 3v3 to the ring, which is connected to the pedal potentiometer, and measures the voltage off the tip (connected to the pot's wiper). When the pedal is disconnected the plug temporarily shorts the ring (3V3) to ground. So I added a 150ohm resistor on the 3v3 supply wire. But I don't know if that's enough and I'm not game enough to try it without being fairly certain I won't destroy another PI.

Is a current limiting resistor enough? If so what value is "enough"?

Or do I need something more complicated to protect the PI?

I don't know exactly how long the short lasts for, but it's well less than a second in practice.

Note: The circuit has an switch in the socket so I can add a little bit of extra resistance when the jack is plugged in. That way I can detect the "unplugged" state (ADC reads full 3V3) and max plugged voltage 3V1 as separate states.

I have setup a Raspberry Pi 4 with a basic Home Assistant installation, and the RPi seems to drop the Wifi connection randomly - i.e. I am not able to connect to it from another device. I can "force" the RPi to properly connect to Wifi again, if I tell the DHCP server (in my router) to reconnect the RPi.

What would be the first thing to check (log files etc.) in the RPi to debug this?

EDIT: I think I found relevant information in /var/log/syslog as follows:

Feb 11 19:37:23 raspberrypi NetworkManager[340]: <warn>  [1581446243.2267] dhcp4 (veth16840be): request timed out
Feb 11 19:37:23 raspberrypi NetworkManager[340]: <info>  [1581446243.2268] dhcp4 (veth16840be): state changed unknown -> timeout
Feb 11 19:37:23 raspberrypi NetworkManager[340]: <info>  [1581446243.2926] dhcp4 (veth16840be): canceled DHCP transaction, DHCP client pid 1096
Feb 11 19:37:23 raspberrypi NetworkManager[340]: <info>  [1581446243.2927] dhcp4 (veth16840be): state changed timeout -> done
Feb 11 19:37:23 raspberrypi NetworkManager[340]: <info>  [1581446243.2941] device (veth16840be): state change: ip-config -> failed (reason 'ip-config-unavailable', sys-iface-state: 'managed')
Feb 11 19:37:23 raspberrypi NetworkManager[340]: <info>  [1581446243.2968] manager: NetworkManager state is now CONNECTED_LOCAL
Feb 11 19:37:23 raspberrypi NetworkManager[340]: <warn>  [1581446243.2990] device (veth16840be): Activation: failed for connection 'Wired connection 6'
Feb 11 19:37:23 raspberrypi NetworkManager[340]: <info>  [1581446243.3009] device (veth16840be): state change: failed -> disconnected (reason 'none', sys-iface-state: 'managed')
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: Withdrawing address record for fe80::d50b:46d2:cac2:6689 on veth16840be.
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: Leaving mDNS multicast group on interface veth16840be.IPv6 with address fe80::d50b:46d2:cac2:6689.
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: Interface veth16840be.IPv6 no longer relevant for mDNS.
Feb 11 19:37:23 raspberrypi dhcpcd[593]: veth16840be: pid 340 deleted route to 169.254.0.0/16
Feb 11 19:37:23 raspberrypi dhcpcd[593]: veth45aca9d: adding default route
Feb 11 19:37:23 raspberrypi dhcpcd[593]: veth16840be: adding route to 169.254.0.0/16
---> Feb 11 19:37:23 raspberrypi dhcpcd[593]: wlan0: deleting route to 192.168.27.0/24
---> Feb 11 19:37:23 raspberrypi dhcpcd[593]: wlan0: deleting default route via 192.168.27.1
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: Withdrawing address record for 169.254.107.61 on veth16840be.
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: Leaving mDNS multicast group on interface veth16840be.IPv4 with address 169.254.107.61.
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: Interface veth16840be.IPv4 no longer relevant for mDNS.
Feb 11 19:37:23 raspberrypi dhcpcd[593]: veth16840be: pid 340 deleted IP address 169.254.107.61/16
Feb 11 19:37:23 raspberrypi dhcpcd[593]: veth16840be: deleting route to 169.254.0.0/16
Feb 11 19:37:23 raspberrypi NetworkManager[340]: <info>  [1581446243.3380] policy: auto-activating connection 'Wired connection 6' (e7dec89a-ed16-3768-b320-3b39f0e5ef0a)
Feb 11 19:37:23 raspberrypi NetworkManager[340]: <info>  [1581446243.3424] device (veth16840be): Activation: starting connection 'Wired connection 6' (e7dec89a-ed16-3768-b320-3b39f0e5ef0a)
Feb 11 19:37:23 raspberrypi NetworkManager[340]: <info>  [1581446243.3436] device (veth16840be): state change: disconnected -> prepare (reason 'none', sys-iface-state: 'managed')
Feb 11 19:37:23 raspberrypi NetworkManager[340]: <info>  [1581446243.3466] manager: NetworkManager state is now CONNECTING
Feb 11 19:37:23 raspberrypi NetworkManager[340]: <info>  [1581446243.3473] device (veth16840be): state change: prepare -> config (reason 'none', sys-iface-state: 'managed')
Feb 11 19:37:23 raspberrypi NetworkManager[340]: <info>  [1581446243.3491] device (veth16840be): state change: config -> ip-config (reason 'none', sys-iface-state: 'managed')
Feb 11 19:37:23 raspberrypi NetworkManager[340]: <info>  [1581446243.3500] dhcp4 (veth16840be): activation: beginning transaction (timeout in 45 seconds)
Feb 11 19:37:23 raspberrypi NetworkManager[340]: <info>  [1581446243.3564] dhcp4 (veth16840be): dhclient started with pid 1117
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: Joining mDNS multicast group on interface veth16840be.IPv6 with address fe80::81ef:965d:9273:bda4.
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: New relevant interface veth16840be.IPv6 for mDNS.
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: Registering new address record for fe80::81ef:965d:9273:bda4 on veth16840be.*.
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: Withdrawing address record for fe80::81ef:965d:9273:bda4 on veth16840be.
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: Leaving mDNS multicast group on interface veth16840be.IPv6 with address fe80::81ef:965d:9273:bda4.
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: Interface veth16840be.IPv6 no longer relevant for mDNS.
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: Joining mDNS multicast group on interface veth16840be.IPv6 with address fe80::a028:68dd:91d:5fee.
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: New relevant interface veth16840be.IPv6 for mDNS.
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: Registering new address record for fe80::a028:68dd:91d:5fee on veth16840be.*.
Feb 11 19:37:23 raspberrypi NetworkManager[340]: <info>  [1581446243.3624] device (veth16840be): ipv6: duplicate address check failed for the fe80::81ef:965d:9273:bda4/64 lft forever pref forever lifetime 194827-0[4294967295,4294967295] dev 23 flags permanent,noprefixroute,tentative src kernel address
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: Withdrawing address record for fe80::a028:68dd:91d:5fee on veth16840be.
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: Leaving mDNS multicast group on interface veth16840be.IPv6 with address fe80::a028:68dd:91d:5fee.
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: Interface veth16840be.IPv6 no longer relevant for mDNS.
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: Joining mDNS multicast group on interface veth16840be.IPv6 with address fe80::d50b:46d2:cac2:6689.
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: New relevant interface veth16840be.IPv6 for mDNS.
Feb 11 19:37:23 raspberrypi avahi-daemon[319]: Registering new address record for fe80::d50b:46d2:cac2:6689 on veth16840be.*.
Feb 11 19:37:23 raspberrypi NetworkManager[340]: <info>  [1581446243.3643] device (veth16840be): ipv6: duplicate address check failed for the fe80::a028:68dd:91d:5fee/64 lft forever pref forever lifetime 194827-0[4294967295,4294967295] dev 23 flags permanent,noprefixroute,tentative src kernel address
Feb 11 19:37:23 raspberrypi NetworkManager[340]: <warn>  [1581446243.3644] device (veth16840be): linklocal6: failed to generate an address: Too many DAD collisions
Feb 11 19:37:23 raspberrypi dhcpcd[593]: veth16840be: probing for an IPv4LL address
Feb 11 19:37:23 raspberrypi dhclient[1117]: DHCPDISCOVER on veth16840be to 255.255.255.255 port 67 interval 8

I marked two lines in the log above with "--->", which could be related to my question. I found three instances of these lines, which matches perfectly with the three times I have experienced the disconnections.

The log files are packed with sections like these (without the lines that I marked), which are repeated every minute or so. It seems NetworkManager is doing "something" to the ethernet (which is not connected) (??).

What could cause the deletion of the WLAN routes in the log, and can I stop NetworkManager from repeating these things with the ethernet?

Thanks :-)

I have setup picamera to stream to a socket with python following the example from Picamera recipes. There, the stream is played back with VLC on another machine which works fine with vlc tcp/h264://my_pi_address:8000/.

If I try to play the stream on the same pi with Omxplayer using omxplayer -o local rtsp://127.0.0.1:8000/ -I the connection seems to crash. Omx reports

[rtsp @ 0x1df84a0] CSeq 1 expected, 0 received.
have a nice day ;)

So how can I use Omxplayer to play the stream on the same pi? I'm on Raspi 3b, Jessie, Python3.4, Omxplayer dfea8c9.

I am sending one integer variable from rpi to arduino. However, it is showing an error. Everything else is correct and here is the code which sends the data:-

write_ser = ser.write(cx.encode())
Attribute error:- 'int' object has no attribute encode

I tried converting to string variable but didn't work. What is the solution?

I am running Ubuntu 16.04 in a VM.
I have successfully SSH'd into my Pi (Running Raspbian) using:
ssh -X <ip of Pi> -l <username>
When I run startlxde, an LXPanel shows up but it's off the desktop display and nothing is shown on it

(The pink rectangle is my LXPanel)

EDIT: I was following this guide

Am I correct in thinking that the LXPanel should should show the pi desktop?

It has been a while since I have last used my raspberry pi 2 model B. When turned on its power strip it started to boot and the code was running down the screen but all of a sudden the screen turned black. I could tell that the screen was still on but just a black set. So naturally I turned to the internet for help. Someone else had a similar problem. Their problem was solved when they wiggled the mouse and pressed some buttons on their keyboard and then pressed Alt and F1. When I attempted this my screen flashed a long column of words that were not code but it had something to do with the fact that there wasn't a warranty. Every time I pressed Alt and F1 this screen would flash but my problem was never fully solved. Please help, I would like to get back to coding. Thank you.

I can config my Pi3 to connect to internet via proxy settings but I can not connect my python script to internet with socket lib Return result always fail

Is there any lib can support this ?

Note: I tried to use pip with --proxy and it can connect & download. Thanks

I am about to begin potty training multiple little boys. I thought of an idea and was hoping somebody knew what kind of hardware I could use...

Ideally there will be a button the size of a sticker in the "sweet spot" of the toilet. When someone urinates on that spot, it would trigger something on a Raspberry Pi GPIO (not sure what to use yet - recording of people cheering? lighting up colorful LED lights? - suggestions welcome).

Now, what can I use for this "sticker"?

Some ideas included moisture sensor, temperature sensor and even an ammonia sensor. I haven't found anything that is in the right form factor.

Happy for all suggestions and inputs, even complicated ones... I am not afraid of getting my hands a little messy ;-)

Thanks in advance! ~Mo

I have a python program that reads data from a USB serial port connected to a computer. The computer sends data packets from a simulation program (I didn't write this).

The data is made of strings of no more than 200 bytes serially with 21 data fields separated by commas at a baud rate of 115200 with 8N1.

In the python program, I have:

ser = serial.Serial(port=PORTNAME, baudrate=115200, timeout=.02)
while True:
    # OTHER STUFF IS IN THE LOOP AS WELL THAT DOESN'T HAVE TO DO WITH THE SERIAL
    time.sleep(0.01)
    data = ser.read(200)

Most of the time, the data will be exactly 21 fields, but sometimes the data variable will be a string that has one entire data packet as well as the beginning of the next one appended to it, and the function that parses each individual data field will obviously return an exception.

Something I tried just for fun is adding a lot of print statements in the loop, which made the exception in the program happen significantly faster. I think it might have to do with the time.

Does anyone know how I can fix this? If not, I can just hard code a hack in the function that parses the data.

I am running retropie 4.x.x the latest version.

When taking a screenshot during a game via the rgui it saves the screenshot with a resolution of 853*480.

Is there a way to get retroarch to save them at a better resolution.

I have changed the video settings in retroarch to make the game look better.

but the screenshot is not taken at the size displayed on the screen and when used as splashscreen it is blown up and distorted unlike when the game is played.

any information or links into the right direction would be much appreciated.

I tried googling but all the links i found are for enabling retroarch screenshot or for getting rgui screenshots and not about screenshot configuration.

I am hoping it is just a screenshot configuration/setting I can change via nano or something.

one thing that might work but would mean using a keyboard or random controller key combo to work is to use raspi2png but apparently the built retroarch screen capture is better. I have yet to test raspi2png as I have a good setup at the moment of retropie and not much space for a full SD card backup on my laptop to be able to test raspi2png without a backup in case i break my retropie.

All help much appreciated and thankyou for taking the time to read my question.

kind regards and have a pleasant day.

If I understand the dmesg output correctly, there is something happening for almost one second around the UART console initialization:

[    1.090771] 20201000.serial: ttyAMA0 at MMIO 0x20201000 (irq = 81, base_baud = 0) is a PL011 rev2
[    1.920577] console [ttyAMA0] enabled

Is there any option, how to reduce this extremely long time? Like:

• kernel compilation options via config?
• kernel parameters passing (cmdline.txt)?
• ARM/GPU configuration options (config.txt)?
• manual UART configuration?
• anything else?

Any hints welcome. Please note, I would like to use the UART as the console.

I tried to create a network so that I can see my pi's output anywhere from within the network.

One pi has the data/ output.

I tried to send the data to another pi which acts as a router(connection via ethernet).

Initially, I could access my first pi's data through an already established network.

Now, I created a new network using another pi, but still when I connect the two pi's via ethernet I could not access the output of first pi and I could not even connect to the network i created.

I'm new to raspbian. So far, what I have done? I did it by following some tutorials.

Please help me how to connect two pi's: one which acts as router and other acts as source of information I want to access.

I'm trying to configure waveshare 35b touchscreen on raspberry 3. I have 2 problems :

• slow refresh rate
• inverted colors (black is white)

Here is my config, (I do not need touchscreen, so it is not configured) :

in config.txt
# enable touchscreen over SPI
device_tree_param=spi=on
dtoverlay=waveshare35b


cat /etc/modules-load.d/touchscreen.conf 
spi-bcm2835
flexfb
fbtft_device

cat /etc/modprobe.d/fbtft.conf 
options flexfb regwidth=16 init=-1,0xb0,0x0,-1,0x11,-2,250,-1,0x3A,0x55,-1,0xC2,0x44,-1,0xC5,0x00,0x00,0x00,0x00,-1,0xE0,0x0F,0x1F,0x1C,0x0C,0x0F,0x08,0x48,0x98,0x37,0x0A,0x13,0x04,0x11,0x0D,0x00,-1,0xE1,0x0F,0x32,0x2E,0x0B,0x0D,0x05,0x47,0x75,0x37,0x06,0x10,0x03,0x24,0x20,0x00,-1,0xE2,0x0F,0x32,0x2E,0x0B,0x0D,0x05,0x47,0x75,0x37,0x06,0x10,0x03,0x24,0x20,0x00,-1,0x36,0x28,-1,0x11,-1,0x29,-3 width=480 height=320
options fbtft_device name=flexfb speed=8000000 gpios=reset:25,dc:24 fps=60 txbuflen=32768

cat /etc/X11/xorg.conf.d/99-fbdev-tft35.conf 
Section "Device"
  #WaveShare SpotPear 3.5", framebuffer 1
  Identifier "WaveShare3.5"
  driver "fbdev"
  Option "fbdev""/dev/fb1"
  Option "ShadowFB""off"
EndSection

I've tried many configurations :

• changing fbtft_device speed
• using other overlay (piscreen)
• test fbtft_device bgr option

But in all cases color are inverted and refresh rate is very slow.

Here is my kernel :

uname -a
Linux a4h-rpi-coffee-machine 4.14.62-1-ARCH #1 SMP Fri Aug 17 05:43:55 UTC 2018 armv7l GNU/Linux

Something is unclear for me, in waveshare35b overlay we can see waveshare35b values for parameters initfps

these parameters are also set in /etc/modprobe.d/fbtft.conf for flexfb configuration. It would appear that loading and configuring flexfb fbtft_device is meaningless. waveshare35b overlay already loads and configure touchscreen. But when I remove /etc/modules-load.d/touchscreen.conf and /etc/modprobe.d/fbtft.conf no driver is loaded.

dmesg |grep graphics
dmesg |grep spi

does not return anything.

Moreover waveshare35b is not in device tree :

sudo ls -R /sys |grep wave

returns nothing. I've recompiled dtbo and copied it to /boot/overlays but it did not change anything.

EDITED : Many thanks @Dirk I've also tried to check logs with vcdbg (to get it on arch :

wget -O vcdbg 'https://github.com/raspberrypi/firmware/blob/master/hardfp/opt/vc/bin/vcdbg?raw=true'&& chmod 0755 vcdbg

and got :

002173.385: Failed to load overlay 'waveshare35b'
002173.484: brfs: File read: /mfs/sd/overlays/waveshare35b.dtb
003251.012: gpioman: gpioman_get_pin_num: pin EMMC_ENABLE not defined
003361.706: Device tree loaded to 0x2eff9900 (size 0x66b6)

Now I'm investigating it.

I just bought a package of sensors online, a few things were really easy to set up, but the DHT11 (3 pin version) temperature and humidity sensor was giving me problems. Here's what I did:

1. Following directions from this site, containing documentation from the supplier I connected the sensor to 3.3V pin and GND.
2. Set up software per guidelines.

The issue was that I wasn't able to see the text file of the sensor, which is supposed to give me the hexadecimal readouts of each sensor. I could see the filesystems for each sensor, but there wasn't anything with a reading. Small issue, and for some reason I thought it could be because I wasn't connecting the DHT11 properly. I found this post on this forum, and also this link from another site which stated that the 5V pin should be used. I connected the 5V to the sensor while I hadn't put any resistors in the circuit at all. The Pi crashed immediately, but then came back online with a recovery screen, and worked without issues for a while.

I still was having issues with the DHT11 for unrelated reasons (I'm new to the RPi), so I again tried to connect the DHT11 to the 5V pin because I wasn't sure if the RPi crashed the first time because I had inadvertently bumped the power supply input. Even though I didn't have the data pin connected to the Pi, this attempt killed my Pi. The LED light for power is on, and the 5v pin is still sending about 5.3V vs the ground pins, but that's about all the Pi does now.

Does this make sense that I fried my RPi by connecting the wrong voltage to the sensor? In other words, is the sensor module both so sensitive to voltages that the Pi itself can produce, and so integral to the Pi's function that I could kill the Pi (admittedly by being careless) like this? Any documentation I can read to avoid dumb mistakes like this in the future?

Thanks, looking forward to getting a new one! And brushing up on Ohm's law...

I have a Raspberry Pi 3 B+ which is currently shut down, and not appearing on my network.

The Raspberry Pi is running MotionEyeOS. And is powered using power over ethernet.

I've tried starting it by sending a Wake on LAN using Fing, and simply unplugging and plugging the ethernet cable into the POE Injector I have.

The big problem I have is that I physically cannot access the Raspberry Pi at this point. And I won't be able to access it for several weeks, and I ideally need it back up and running as fast as possible.

Any help really would be appreciated.