Go to advanced search

by tastycrust
Fri Oct 04, 2019 2:58 am
Forum: Automation, sensing and robotics
Topic: Any easy way to sync two RPis?
Replies: 9
Views: 3439

Re: Any easy way to sync two RPis?

One quick question! I don't understand how you run the script in both raspberries. Sorry to dig up an old thread to answer a stale question, but I'm picking up this project again after putting it on the back burner for a bit, and realized I never answered this. Each "eye" is running as an independe...
by tastycrust
Sun Mar 11, 2018 4:04 pm
Forum: Automation, sensing and robotics
Topic: Lowest latency way to send picamera frames (numpy array) over LAN for OpenCV analysis?
Replies: 19
Views: 3928

Re: Lowest latency way to send picamera frames (numpy array) over LAN for OpenCV analysis?

So I have two RPi0w's each set up to capture live video frames in a python script using picamera, and I have them synced very closely in the hope to do binocular vision analysis on a PC running on the same local network. ( Details in this thread ) However, I'm not sure what the best method is to tr...
by tastycrust
Thu Mar 08, 2018 12:48 am
Forum: Automation, sensing and robotics
Topic: Lowest latency way to send picamera frames (numpy array) over LAN for OpenCV analysis?
Replies: 19
Views: 3928

Re: Lowest latency way to send picamera frames (numpy array) over LAN for OpenCV analysis?

I'd try using GStreamer - create a GStreamer server on the Pi, connect to it using GStreamer client on the analysis side and grab individual frames from the video stream. Thanks for the suggestion! I'll look into that as I muddle through the various technical challenges of doing this. As an update,...
by tastycrust
Thu Mar 01, 2018 8:36 pm
Forum: Automation, sensing and robotics
Topic: Lowest latency way to send picamera frames (numpy array) over LAN for OpenCV analysis?
Replies: 19
Views: 3928

Re: Lowest latency way to send picamera frames (numpy array) over LAN for OpenCV analysis?

https://www.pyimagesearch.com/2017/09/04/raspbian-stretch-install-opencv-3-python-on-your-raspberry-pi/ worked for me - you do have to follow the instructions exactly! (One or two of the packages have been updated since that post was written, and there's no problem using the latest as long as you r...
by tastycrust
Thu Mar 01, 2018 4:52 pm
Forum: Automation, sensing and robotics
Topic: Lowest latency way to send picamera frames (numpy array) over LAN for OpenCV analysis?
Replies: 19
Views: 3928

Re: Lowest latency way to send picamera frames (numpy array) over LAN for OpenCV analysis?

I was able to modify the script to work on the RPi0w, I think, but ran into problems compiling OpenCV 3 on the desktop, which is running Debian 9 (Stretch), and there are some dependency issues I haven't figured out how to solve yet. Most notably OpenCV needs gcc/g++ to be version 4.9 or lower, and ...
by tastycrust
Wed Feb 28, 2018 11:11 pm
Forum: Graphics, sound and multimedia
Topic: Troubleshooting USB mic issue ("no such file or directory" error)
Replies: 2
Views: 7470

Re: Troubleshooting USB mic issue ("no such file or directory" error)

Thank you for that! Sure enough, the first example works. The card is listed in /proc/asound/cards, but there is no ~/.asoundrc or /etc/asound.conf file, though, so I created the latter and put this in it: pcm.!default { type hw card 1 } ctl.!default { type hw card 1 } I got that by tweaking what wa...
by tastycrust
Wed Feb 28, 2018 10:06 pm
Forum: Automation, sensing and robotics
Topic: Lowest latency way to send picamera frames (numpy array) over LAN for OpenCV analysis?
Replies: 19
Views: 3928

Re: Lowest latency way to send picamera frames (numpy array) over LAN for OpenCV analysis?

I doubt it can do the level of analysis I'm hoping to achieve with my PC, The compute module 3 has reasonable computer power quad core CPU + GPU and openCV is very optimized to use multi processing across all processors. Yes it will have less computing power than your PC but my guess is that the wh...
by tastycrust
Wed Feb 28, 2018 9:40 pm
Forum: Graphics, sound and multimedia
Topic: Troubleshooting USB mic issue ("no such file or directory" error)
Replies: 2
Views: 7470

Troubleshooting USB mic issue ("no such file or directory" error)

I've never tried to use a microphone in Raspbian, so I'm sure that I'm just missing some obvious step here. I plugged in a USB mic to my RPi0W, and arecord sees that it exists: [email protected]:~ $ arecord -l **** List of CAPTURE Hardware Devices **** card 1: Device [USB PnP Sound Device], device 0: USB A...
by tastycrust
Wed Feb 28, 2018 8:13 pm
Forum: Networking and servers
Topic: iperf seems to give inaccurate results for PPP over UART?
Replies: 1
Views: 399

Re: iperf seems to give inaccurate results for PPP over UART?

OK, to answer my own question, I guess TCP doesn't really work as iperf expects over PPP. When I used UDP instead, the numbers are exactly as expected: [email protected]:~ $ iperf -s -u ------------------------------------------------------------ Server listening on UDP port 5001 Receiving 1470 byte datag...
by tastycrust
Wed Feb 28, 2018 7:50 pm
Forum: Networking and servers
Topic: iperf seems to give inaccurate results for PPP over UART?
Replies: 1
Views: 399

iperf seems to give inaccurate results for PPP over UART?

Can anyone explain how I'm getting such fast transfer rates according to iperf? I set up two RPi0w's to be connected via PPP over UART, as explained in this post . I set the baud rate to 1M, so I thought that when I tested the data transfer speeds it would be about 1Mbps, but using iperf I'm getting...
by tastycrust
Wed Feb 28, 2018 6:18 pm
Forum: Automation, sensing and robotics
Topic: Lowest latency way to send picamera frames (numpy array) over LAN for OpenCV analysis?
Replies: 19
Views: 3928

Re: Lowest latency way to send picamera frames (numpy array) over LAN for OpenCV analysis?

8 fps 640 x 480 x 24-bit raw frames would require a network transfer speed of ~ 59 MB/s. I think that's rather more than any network interface the Raspberry Pi Zero supports. Ahh, that's good to know. What is the max speed supported by the wifi interface? Would it be able to handle 320x240 instead?...
by tastycrust
Wed Feb 28, 2018 2:39 pm
Forum: Automation, sensing and robotics
Topic: Lowest latency way to send picamera frames (numpy array) over LAN for OpenCV analysis?
Replies: 19
Views: 3928

Re: Lowest latency way to send picamera frames (numpy array) over LAN for OpenCV analysis?

You could maybe approach the problem from a different angle. Establish an accurate reference clock at each Pi, and keep them in sync. Then tag each set of data with the time. This way the latency doesn't greatly matter, as long as the average throughput is adequate. Note: When I say 'accurate' for ...
by tastycrust
Tue Feb 27, 2018 10:33 pm
Forum: Automation, sensing and robotics
Topic: Lowest latency way to send picamera frames (numpy array) over LAN for OpenCV analysis?
Replies: 19
Views: 3928

Re: Lowest latency way to send picamera frames (numpy array) over LAN for OpenCV analysis?

At the moment I'm starting with low resolution (640x480), low framerate (8fps), but with the frames synced to within about 5 milliseconds left and right (so that the low framerate doesn't cause frames to be out of sync). So, it's well within what the RPi0 can handle in terms of the data pipeline fro...
by tastycrust
Tue Feb 27, 2018 9:36 pm
Forum: Automation, sensing and robotics
Topic: Lowest latency way to send picamera frames (numpy array) over LAN for OpenCV analysis?
Replies: 19
Views: 3928

Lowest latency way to send picamera frames (numpy array) over LAN for OpenCV analysis?

So I have two RPi0w's each set up to capture live video frames in a python script using picamera, and I have them synced very closely in the hope to do binocular vision analysis on a PC running on the same local network. ( Details in this thread ) However, I'm not sure what the best method is to tra...
by tastycrust
Mon Feb 26, 2018 7:11 pm
Forum: Networking and servers
Topic: Setting up a PPP server and client over GPIO/UART?
Replies: 10
Views: 4908

Re: Setting up a PPP server and client over GPIO/UART?

Just thought I'd give a final update on this thread since I got everything working OK. I ended up just flashing backed up images to the SD cards from before I started messing with serial port stuff, then starting over again with a modified version of the instructions in this instructable . Those ins...
by tastycrust
Mon Feb 26, 2018 6:06 pm
Forum: Troubleshooting
Topic: That "oops" moment of GPIO dyslexia
Replies: 5
Views: 556

Re: That "oops" moment of GPIO dyslexia

Good news! It was just that I had messed up the wpa_supplicant files and after reboot they weren't connecting to wifi anymore. WHEW!
by tastycrust
Fri Feb 23, 2018 8:05 pm
Forum: Camera board
Topic: Best way to use picamera's framerate_delta property to sync two separate cameras?
Replies: 0
Views: 289

Best way to use picamera's framerate_delta property to sync two separate cameras?

I took a first crack at syncing video frames on two pi zeros using framerate_delta, as described in this thread , which works OK for 8fps (within about +/- 4ms once it gets humming), but has more trouble at higher framerates (more like +/- 10ms at 30fps). I'm going to work on improving the clock syn...
by tastycrust
Fri Feb 23, 2018 3:42 pm
Forum: Troubleshooting
Topic: That "oops" moment of GPIO dyslexia
Replies: 5
Views: 556

Re: That "oops" moment of GPIO dyslexia

I'll put it out of my mind until Monday... The problem is I soldered the headers on the back side of the boards (so they stick out the back of the official case), so I have to do a mirror image of the pinout in my head every time. I should probably print labels for the cases to avoid a repeat in the...
by tastycrust
Fri Feb 23, 2018 1:26 pm
Forum: Troubleshooting
Topic: That "oops" moment of GPIO dyslexia
Replies: 5
Views: 556

Re: That "oops" moment of GPIO dyslexia

Ahh, then I fear I must have messed up something with wpa_supplicant.conf when I added my wifi hotspot yesterday, because I fixed the wiring and rebooted, but when I scan the hotspot network neither pi shows up.

Now I'll be anxious until I can find out....
by tastycrust
Fri Feb 23, 2018 1:17 pm
Forum: Troubleshooting
Topic: That "oops" moment of GPIO dyslexia
Replies: 5
Views: 556

That "oops" moment of GPIO dyslexia

So I set up a Pi0W -> Pi0W serial connection last night using header wires, and got everything working great. But, this morning, I decided to cut some 22awg wire to size and make them look tidier, so I powered off the zeros, swapped wires, and booted up. 1 minute later, when I still couldn't log in ...
by tastycrust
Fri Feb 23, 2018 12:30 am
Forum: Networking and servers
Topic: Setting up a PPP server and client over GPIO/UART?
Replies: 10
Views: 4908

Re: Setting up a PPP server and client over GPIO/UART?

Of course that was premature celebration. I'm pulling my hair out again. Both zeros work fine in loopback, but when I connect them to each other, nothing is sent via minicom. Wired as follows: Tx1==>Rx2 Rx1==>Tx2 Gnd1=>Gnd2 I'm using the exact same settings in minicom on both cards, but I feel I mus...
by tastycrust
Thu Feb 22, 2018 6:13 pm
Forum: Networking and servers
Topic: Setting up a PPP server and client over GPIO/UART?
Replies: 10
Views: 4908

Re: Setting up a PPP server and client over GPIO/UART?

Solved! Just a word to the wise: If you are going to switch between device tree overlays, make sure you first do a reboot without any overlay before doing the second overlay. In this case, I first tried the pi3-miniuart-bt overlay, but since Bluetooth seemed to be broken using the miniuart, I then s...
by tastycrust
Thu Feb 22, 2018 5:32 pm
Forum: Networking and servers
Topic: Setting up a PPP server and client over GPIO/UART?
Replies: 10
Views: 4908

Re: Setting up a PPP server and client over GPIO/UART?

For "hardware handshaking" do you mean the setting "Hardware Flow Control"? Yes. If should be turned off if you are just using a 3-wire connection. OK, I've changed that, saved as default, restarted (just in case it didn't take effect immediately), but still nothing when I type into minicom. Is the...
by tastycrust
Thu Feb 22, 2018 5:08 pm
Forum: Networking and servers
Topic: Setting up a PPP server and client over GPIO/UART?
Replies: 10
Views: 4908

Re: Setting up a PPP server and client over GPIO/UART?

I've enabled the serial port in raspi-config (and disabled console login), This should be enough. I dont know why people bother messing with the BT, it should have nothing to do with UART pins. This is why: By default, on Raspberry Pis equipped with the wireless/Bluetooth module (Raspberry Pi 3 and...
by tastycrust
Thu Feb 22, 2018 4:14 pm
Forum: Networking and servers
Topic: Setting up a PPP server and client over GPIO/UART?
Replies: 10
Views: 4908

Re: Setting up a PPP server and client over GPIO/UART?

Hmm... so I'm having trouble getting the serial port to work at all. I've enabled the serial port in raspi-config (and disabled console login), then disabled the hciuart service: sudo systemctl disable hciuart I then added the following line to /boot/config.txt: dtaoverlay=pi3-disable-bt I rebooted ...

Go to advanced search