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by OutsourcedGuru
Tue Aug 20, 2019 7:33 pm
Forum: Advanced users
Topic: Connect two Raspberries via USB Type-A crossover cable
Replies: 8
Views: 525

Re: Connect two Raspberries via USB Type-A crossover cable

It won't work, can't work. USB is not the same as UART / GPIO linking. You would need two USB-to-Serial adapters then cross-over the Rx/Tx pins of the two serial modules, and have their 0V linked. Connecting the UART on two Pi's, both as /dev/serial0 should work. It worked between a Pi and an Ardui...
by OutsourcedGuru
Tue Aug 20, 2019 7:30 pm
Forum: Advanced users
Topic: Connect two Raspberries via USB Type-A crossover cable
Replies: 8
Views: 525

Re: Connect two Raspberries via USB Type-A crossover cable

There is no such thing as a USB-A to USB-A crossover cable. The 4 USB sockets on a Pi are host mode only and you can't connect host to host. If you only want a single low speed serial link between the two Pi boards then use 2x USB to serial adapters and cross over the UART connection. Up to you if ...
by OutsourcedGuru
Tue Aug 20, 2019 7:06 pm
Forum: Advanced users
Topic: Connect two Raspberries via USB Type-A crossover cable
Replies: 8
Views: 525

Connect two Raspberries via USB Type-A crossover cable

I'm trying to attempt something so that I might test serial communications between two standard Raspberry Pi 3B computers. It's so that I can develop some serial-based software so it doesn't have to be pretty. * Most of the tutorials I've seen involve using the GPIO pins in order to talk over serial...
by OutsourcedGuru
Fri Aug 16, 2019 5:49 pm
Forum: OpenGLES
Topic: RPi 4 OpenGL ES 3.0 ShaderToy to download (100+ examples)
Replies: 31
Views: 4618

Re: RPi 4 OpenGL ES 3.0 ShaderToy to download (100+ examples)

Tried this locally on Raspbian Buster Desktop 4.9 with Raspberry Pi 4B (4GB) and it works great (noting that I adjusted the `gpu_mem` to 128 as suggested). It brings up another window to display the graphical output. This is using a SunFounder 10.1" TFT display for what it's worth and it's attached ...
by OutsourcedGuru
Fri Aug 09, 2019 5:30 pm
Forum: Troubleshooting
Topic: Raspberry Pi 4B not working with Kivy
Replies: 4
Views: 222

Re: Raspberry Pi 4B not working with Kivy

I note that on a working Raspberry Pi 3B, this is seen in the Kivy log: [INFO ] Window: Provider: egl_rpi [INFO ] GL: Using the "OpenGL ES 2" graphics system [INFO ] GL: Backend used <gl> [INFO ] GL: OpenGL version <OpenGL ES 2.0> [INFO ] GL: OpenGL vendor <Broadcom> [INFO ] GL: OpenGL renderer <Vid...
by OutsourcedGuru
Wed Aug 07, 2019 8:22 pm
Forum: Troubleshooting
Topic: HELP! Rpi4 stuck at rainbow stage after firmware update.
Replies: 10
Views: 847

Re: HELP! Rpi4 stuck at rainbow stage after firmware update.

I wouldn't recommend rpi-update to anyone who's not developing hardware drivers, for example.

rpi-update => bricked raspberry
by OutsourcedGuru
Wed Aug 07, 2019 8:16 pm
Forum: Troubleshooting
Topic: No audio through 3.5 jack pi 4
Replies: 3
Views: 213

Re: No audio through 3.5 jack pi 4

If you're trying to use something like `aplay` to play a file then it's probably good to first run `alsamixer` to adjust the volume. To me, it seems like setting the volume there to 40 was perfect for the Raspberry Pi 3B but had to set it much higher on the Raspberry Pi 4B as I recall (80?).
by OutsourcedGuru
Wed Aug 07, 2019 8:12 pm
Forum: Troubleshooting
Topic: Raspberry Pi 4B not working with Kivy
Replies: 4
Views: 222

Raspberry Pi 4B not working with Kivy

I have yet to be able to get even the simplest of Kivy examples to work. Tried both Buster Lite and Buster Desktop from 7/10/2019 Added the `KIVY_GL_BACKEND=gl` to the environment Commented-out the `dtoverlay=vc4-fkms-v3d.` in config.txt Tried selecting HDMI with `KIVY_BCM_DISPMANX_ID=2` Edit to `.k...
by OutsourcedGuru
Wed Aug 07, 2019 7:51 pm
Forum: Troubleshooting
Topic: Raspberry Pi 4 temperature
Replies: 529
Views: 130706

Re: Raspberry Pi 4 temperature

I'm noting that I purchased/installed the Zebra 4 fan case and the CPU temperature is reporting around 39C (reasonably idle with 35 processes running), for what it's worth.
by OutsourcedGuru
Mon Jan 28, 2019 4:49 pm
Forum: Other programming languages
Topic: NPM start on start-up? Help wanted
Replies: 12
Views: 10051

Re: NPM start on start-up? Help wanted

> "Just drop your service file into /etc/systemd/system and away you go." I spent hours trying to get this "just" version to work. I'm suggesting that with Raspbian Stretch it needs to be in the way I'm describing. I will note that the "After" line in the [Unit] section needs to instead be: After=ne...
by OutsourcedGuru
Fri Jan 25, 2019 10:16 pm
Forum: Other programming languages
Topic: NPM start on start-up? Help wanted
Replies: 12
Views: 10051

Re: NPM start on start-up? Help wanted

For anyone trying to follow along with Raspbian Stretch, I found that "/etc/systemd" was not the place where it wanted to see these "*.service" files. Also, the default file restrictions appear to be wrong as seen above. Path: /lib/systemd/system/yourapp.service Rights: sudo chmod 644 /lib/systemd/s...
by OutsourcedGuru
Tue May 29, 2018 12:20 am
Forum: Advanced users
Topic: Raspi3 to Raspi0 via USB serial communications
Replies: 8
Views: 786

Re: Raspi3 to Raspi0 via USB serial communications

Okay, was able to get the Raspi3 and Raspi0 to talk via minicom so I'm guessing that I'm good to go now. Thanks.
by OutsourcedGuru
Mon May 28, 2018 11:21 pm
Forum: Advanced users
Topic: Raspi3 to Raspi0 via USB serial communications
Replies: 8
Views: 786

Re: Raspi3 to Raspi0 via USB serial communications

[x] Added `dtoverlay=pi3-disable-bt` to `/boot/config.txt` [x] In `sudo raspi-config` -> Interfacing -> Serial, selected "No" and "Yes" The serial login shell is disabled The serial interface is enabled [x] This appears to have edited `/boot/cmdline.txt` from `console=serial0,115200` to `console=tty...
by OutsourcedGuru
Mon May 28, 2018 10:38 pm
Forum: Advanced users
Topic: Raspi3 to Raspi0 via USB serial communications
Replies: 8
Views: 786

Re: Raspi3 to Raspi0 via USB serial communications

Also, if I disable the console's use of the mini UART, does this prevent SSH from working to remotely access the Raspberry Pi Zero W?

Reference: https://www.raspberrypi.org/documentati ... on/uart.md
by OutsourcedGuru
Mon May 28, 2018 9:29 pm
Forum: Advanced users
Topic: Raspi3 to Raspi0 via USB serial communications
Replies: 8
Views: 786

Re: Raspi3 to Raspi0 via USB serial communications

If you disable Bluetooth, you can use both UARTS freely. ghans Okay, that's dtoverlay=pi3-disable-bt in the `/boot/config.txt` file and easy enough. Now that I know if it's possible, it would be good to figure out how to make that happen. If someone can prompt me a little with the setup, that would...
by OutsourcedGuru
Mon May 28, 2018 6:47 pm
Forum: Advanced users
Topic: Raspi3 to Raspi0 via USB serial communications
Replies: 8
Views: 786

Re: Raspi3 to Raspi0 via USB serial communications

That's a shame. I'd thought that the PWR connection could also serve as a serial USB connection.

Okay, assume that the RAMPS-side of the Raspberry Pi Zero W is connected via the GPIO pins. Any thoughts?
by OutsourcedGuru
Sun May 27, 2018 7:46 pm
Forum: Advanced users
Topic: Raspi3 to Raspi0 via USB serial communications
Replies: 8
Views: 786

Raspi3 to Raspi0 via USB serial communications

It's my intent to insert a Raspberry Pi Zero W inline between what would normally be: _______......._____________________________......___________________________ Raspi3 | -> | USB Type A/B adapter cable | -> | 3D printer's RAMPS board _______......._____________________________......_______________...
by OutsourcedGuru
Tue Jul 11, 2017 4:35 pm
Forum: Other programming languages
Topic: JavaScript
Replies: 33
Views: 6796

Re: JavaScript

IBM recently listed their " most important (computer) languages to learn for 2017 ". In order: Java, JavaScript, Python, C#/C++, SQL, Swift Apart from the name similarity, Javascript has nothing in common with Java. It is used by 94.4% of the websites and that’s unlikely to change. Anyone with a foc...
by OutsourcedGuru
Wed Jul 05, 2017 10:31 pm
Forum: General discussion
Topic: Reading GPIO with Javascript [NOT NODE]
Replies: 7
Views: 2782

Re: Reading GPIO with Javascript [NOT NODE]

There is a way to talk to the GPIO devices via a device strategy. /sys/class/gpio Do some research about how you might "export" something you're interested in monitoring (like a certain pin). An example command to export pin 4, for example, might be: sudo echo 4 > /sys/class/gpio/export ...which in ...
by OutsourcedGuru
Wed Jul 05, 2017 10:21 pm
Forum: Beginners
Topic: Code speed GUI vs. command line
Replies: 8
Views: 1391

Re: Code speed GUI vs. command line

I kind of want to suggest that you go to school on this file: https://github.com/Wallacoloo/Raspberry-Pi-DMA-Example/blob/master/dma-example.c ...but that involves a fair bit of work. Using direct memory access (DMA) is what a lot of high-speed apps like FM transmission require to get things working...
by OutsourcedGuru
Wed Jul 05, 2017 10:02 pm
Forum: Beginners
Topic: Code speed GUI vs. command line
Replies: 8
Views: 1391

Re: Code speed GUI vs. command line

Well... the Pi will scale back the processor if it's too hot. You could wait for it to happen again and then use a hair dryer (with a no-heat option) to blow air across the CPU to see it it runs faster after a bit.
by OutsourcedGuru
Mon Jul 03, 2017 10:53 pm
Forum: Networking and servers
Topic: Running multiple pi's on a tractor
Replies: 26
Views: 4799

Re: Running multiple pi's on a tractor

If it were me, I'd start with a 15A car inverter and attaching that to the battery with an inline fuse (now AC in typical home-style 115VAC connection) and plug into that six of the Radio Shack USB chargers and power the first 24 Raspis using the typical USB style of connection. I'd treat the 25th m...
by OutsourcedGuru
Mon Jul 03, 2017 10:42 pm
Forum: Advanced users
Topic: Where is PP1 and PP6 on Raspberry Pi Zero W?
Replies: 7
Views: 3348

Re: Where is PP1 and PP6 on Raspberry Pi Zero W?

Typically, you might break off and solder a two-pin header to pins 4 & 6 (5V & ground) and then attach a standard red/black jumper to that.

http://www.mouser.com/images/harwin/lrg/m20-977.jpg
https://cdn.sparkfun.com//assets/parts/ ... 362-02.jpg
by OutsourcedGuru
Mon Jul 03, 2017 10:30 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SainSmart 8-Channel 5V Relay Module VS SainSmart 8-Channel
Replies: 20
Views: 16964

Re: SainSmart 8-Channel 5V Relay Module VS SainSmart 8-Chan

It helps to know what these things often are inside the little black box: https://en.wikipedia.org/wiki/Solid-state_relay (It might be a triac, SCR, MOSFET or transistor.) A typical transistor-based amplifier by its nature reverses the output (low in, high out) so they're sometimes called an inverte...
by OutsourcedGuru
Mon Jul 03, 2017 10:09 pm
Forum: General discussion
Topic: STICKY: Introduce yourself!
Replies: 3518
Views: 103190

Re: Introduce yourself!

I'm Michael and an avid fan of the Raspberry Pi 3 (and the Zero W). I probably have about seven of them now and another in the mail to me (along with a big collection of accessories). I've created a Raspberry Pi 3 supercomputer, I'm working on an Arduino->Pi port for the OSEPP tank including a remot...

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