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by jbeale
Sat Sep 25, 2021 11:19 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2S mic works with arecord, but not with ffmpeg
Replies: 1
Views: 260

Re: I2S mic works with arecord, but not with ffmpeg

I found using arecord first then piping into ffmpeg does work.
I would have thought you could also do this directly from ffmpeg, but I do not know how.

Code: Select all

arecord -D plughw:1 -c1 -r 24000 -d 10 -f S32_LE -t raw -v | ffmpeg -f s32le -ar 24k -ac 1 -i pipe: test.wav
by jbeale
Sat Sep 25, 2021 8:49 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2S mic works with arecord, but not with ffmpeg
Replies: 1
Views: 260

I2S mic works with arecord, but not with ffmpeg

I got the Adafruit I2S microphone SPH0645LM4H and hooked it up to a Pi4 as described here: https://learn.adafruit.com/adafruit-i2s-mems-microphone-breakout/raspberry-pi-wiring-test After installing the software described on that page, the I2S device does show up: $ arecord -l **** List of CAPTURE Ha...
by jbeale
Mon Aug 23, 2021 5:13 pm
Forum: Off topic discussion
Topic: What was your first computer?
Replies: 598
Views: 257398

Re: What was your first computer?

First PC I used was an Exidy Sorcerer (borrowed one summer from a family friend). It could do some neat things with character-mapped graphics, my brother and I programmed robot games on it. Program storage was basically a modem recorded on audio cassette tape, and it was super unreliable. First one ...
by jbeale
Sun Aug 22, 2021 8:56 pm
Forum: Troubleshooting
Topic: vchiq: invalid/closed service 15
Replies: 0
Views: 138

vchiq: invalid/closed service 15

I recently these messages show up in a 'dmesg' list, which I do not recall seeing before. [694583.364658] vchiq: 0: prs DATA@deaffb34 (66->15) - invalid/closed service 15 [742523.750085] vchiq: 0: prs DATA@be61ac1d (66->15) - invalid/closed service 15 This is a relatively recent install of Raspberry...
by jbeale
Sat Aug 21, 2021 6:10 am
Forum: General discussion
Topic: "Raspberry Shake" network in Haiti
Replies: 0
Views: 213

"Raspberry Shake" network in Haiti

I thought this article in Nature was interesting. Apparently the best local data describing ground movement from the recent Haiti earthquake and its aftershocks comes not from a government system, but from a "citizen science" network of home-based seismometers using the Raspberry Shake, a ...
by jbeale
Mon Aug 16, 2021 7:30 am
Forum: Automation, sensing and robotics
Topic: advice for low-noise sensor performance
Replies: 5
Views: 1104

Re: advice for low-noise sensor performance

Detection range depends on the size of the target. For a person, maybe about 50 feet and for a car I was seeing out to 250 feet but I did add a small horn antenna to help the range a little.
by jbeale
Thu Aug 12, 2021 5:44 pm
Forum: Camera board
Topic: HQ camera mount screws
Replies: 2
Views: 437

Re: HQ camera mount screws

Here's a video from the repaired HQ camera assembly. In this case I was using PiKrellCam, and towards the end I took some full-resolution still photos during the 1080p video recording, which briefly interrupted the video as the camera switched modes. https://www.youtube.com/watch?v=yzqq5waZOQo Fawn_...
by jbeale
Tue Aug 10, 2021 7:02 pm
Forum: Camera board
Topic: HQ camera mount screws
Replies: 2
Views: 437

Re: HQ camera mount screws

Dodged the bullet this time. The screws are M2, and it looks like 9 mm is as much as you can use. I had some M2-10mm which I adjusted down a bit with a grinder. That gives me a few more threads of engagement, and I added some superglue for good measure. And this time, I'm planning to not drop it. ht...
by jbeale
Tue Aug 10, 2021 4:46 am
Forum: Camera board
Topic: HQ camera mount screws
Replies: 2
Views: 437

HQ camera mount screws

It is totally my fault for dropping the HQ camera assembly while mounted. I do note that the 1/4-20 threaded part of the camera lens mount is attached to the lens mount ring with what appears to be only two threads worth of some very small screws (M2.5 maybe?) Consequently, they are none too strong....
by jbeale
Tue Jul 13, 2021 5:04 pm
Forum: General discussion
Topic: Power Supply for Raspberry 4 bad design for Australia
Replies: 89
Views: 4018

Re: Power Supply for Raspberry 4 bad design for Australia

Not to make any excuses about awkward designs, but if you look at any power supply that is sold worldwide you will see an impressive number of different logos, type certifications etc. on the case. AIUI quite a few countries require power supply testing that only their own test houses are certified ...
by jbeale
Fri Jul 09, 2021 3:13 pm
Forum: Python
Topic: trying to explain Python to a beginner
Replies: 6
Views: 705

Re: trying to explain Python to a beginner

Thank you for those notes. Neither Scratch nor this particular Python IDE have single-step debugging, so I was trying to wave the arrow cursor around to point out the lines, but syntax highlighting could be a help. In the past I've found the YouTube auto caption to be mostly accurate, so I didn't bo...
by jbeale
Fri Jul 09, 2021 4:56 am
Forum: Python
Topic: trying to explain Python to a beginner
Replies: 6
Views: 705

trying to explain Python to a beginner

Suppose I was trying to explain a loop to someone who's never used Python. Here is a 2-minute video of my attempt (first using Scratch, then doing a similar thing in Python). Do you think this makes sense? How could it be improved (apart from audio problems)? https://www.youtube.com/watch?v=JQJHde4r...
by jbeale
Sun Jul 04, 2021 8:56 pm
Forum: MicroPython
Topic: good edge timing accuracy in MicroPython?
Replies: 50
Views: 4770

Re: good edge timing accuracy in MicroPython?

Hi, This thread has been so useful, thank you so much for sharing. I must admit I'm a little lost though! I would like to modify the code just to give the time difference between the two leading edges. The reference pulse leading edge may occur before or after the "test" pulse leading edg...
by jbeale
Sat Jul 03, 2021 9:14 pm
Forum: Staffroom, classroom and projects
Topic: remote learning setup: good webcam?
Replies: 0
Views: 1575

remote learning setup: good webcam?

This is RPi-related only in that I'm using a RPi Pico in a class on programming microcontrollers. I'm posting my question here because I think there's smart people here. The class is being done remote over Zoom, so I'm visible only via webcam. My standard laptop built-in webcam is not so impressive,...
by jbeale
Tue Jun 22, 2021 3:45 pm
Forum: General discussion
Topic: recommend scientific graphing program?
Replies: 12
Views: 929

Re: recommend scientific graphing program?

I recently came across Veusz https://veusz.github.io/ which is a reasonably capable, open-source and cross-platform plotting package. My initial experience is that it mostly does what I want, and I was able to simply install it on Windows, and an Intel-based Linux box. However I have so far been una...
by jbeale
Thu Jun 10, 2021 9:47 pm
Forum: Troubleshooting
Topic: lockup on 4b : Firmware transaction timeout ?
Replies: 25
Views: 2032

Re: lockup on 4b : Firmware transaction timeout ?

This is a 4GB Pi4. After reading this, I upped my GPU memory so it is now $ vcgencmd get_mem gpu gpu=256M My swap is 100 MB. Right now 'top' reports top - 14:44:18 up 2 days, 3:02, 2 users, load average: 3.05, 3.25, 3.22 Tasks: 195 total, 2 running, 193 sleeping, 0 stopped, 0 zombie %Cpu(s): 9.1 us,...
by jbeale
Tue Jun 08, 2021 6:33 pm
Forum: Troubleshooting
Topic: lockup on 4b : Firmware transaction timeout ?
Replies: 25
Views: 2032

Re: lockup on 4b : Firmware transaction timeout ?

pi@rp49:~ $ vcgencmd get_mem gpu gpu=76M Looks like that is not enough. I don't see any kind of memory being set in my /boot/config.txt so that is some sort of default, I suppose? EDIT: apparently yes, 76 is the default for 1G+ memory systems. https://www.raspberrypi.org/documentation/configuration...
by jbeale
Tue Jun 08, 2021 4:53 pm
Forum: MicroPython
Topic: Pico as USB memory device ?
Replies: 28
Views: 2339

Re: Pico as USB memory device ?

Very interesting example hippy. One item, I wonder which version of CircuitPython you are using? I tried this code on my Pico and got a boot_out.txt file saying: Adafruit CircuitPython 6.3.0 on 2021-06-01; Raspberry Pi Pico with rp2040 boot.py output: Traceback (most recent call last): File "bo...
by jbeale
Tue Jun 08, 2021 4:31 pm
Forum: Troubleshooting
Topic: lockup on 4b : Firmware transaction timeout ?
Replies: 25
Views: 2032

Re: lockup on 4b : Firmware transaction timeout ?

"Firmware transaction timeout" just happened again. [ 2859.332873] ------------[ cut here ]------------ [ 2859.332912] WARNING: CPU: 3 PID: 3153 at drivers/firmware/raspberrypi.c:64 rpi_firmware_transaction+0xec/0x128 [ 2859.332924] Firmware transaction timeout [ 2859.332935] Modules linke...
by jbeale
Mon Jun 07, 2021 4:36 am
Forum: Automation, sensing and robotics
Topic: advice for low-noise sensor performance
Replies: 5
Views: 1104

Re: advice for low-noise sensor performance

In case you're wondering what you can do with a sensor like that, here's one: point it straight up into the sky. On a clear day you see nothing except an occasional blip from a bird or insect flying inside the radar beam. However, when it rains you can tell not only how heavy the rain is, but also h...
by jbeale
Mon Jun 07, 2021 4:01 am
Forum: MicroPython
Topic: Pico as USB memory device ?
Replies: 28
Views: 2339

Re: Pico as USB memory device ?

Wow, thanks everyone for the additional discussion of this issue. Indeed what I was hoping for was a general-purpose, non-OS-specific solution that would enable existing systems running on various legacy hardware to work "as-is" with a new sensor device, so long as they could access a file...
by jbeale
Sat Jun 05, 2021 3:42 am
Forum: MicroPython
Topic: Pico as USB memory device ?
Replies: 28
Views: 2339

Re: Pico as USB memory device ?

when emulating a normal mass-storage device, the host computer assumes it has exclusive control of the flash memory and it can cache things it has read, because its not expecting the contents to change on their own usb camera and phone stuff has had the exact same limitation, the device cant use th...
by jbeale
Sat Jun 05, 2021 3:34 am
Forum: MicroPython
Topic: Pico as USB memory device ?
Replies: 28
Views: 2339

Re: Pico as USB memory device ?

I was able to try the CircuitPython example that logs data to the internal flash memory, but it doesn't work exactly the way I had in mind. In particular, the host PC mounts the board's filesystem in "Read Only" mode and it can read the file exactly once. Either on the host side or the cli...
by jbeale
Sat Jun 05, 2021 2:41 am
Forum: Troubleshooting
Topic: lockup on 4b : Firmware transaction timeout ?
Replies: 25
Views: 2032

Re: lockup on 4b : Firmware transaction timeout ?

Happened twice to me again today. Most recently I got "Firmware transaction timeout" and then "raspberrypi-clk soc:firmware:clocks: Failed to change fw-clk-v3d frequency: -110 bcm2835_mmal_vchiq: timed out waiting for sync completion" I have to reboot from another system, or powe...
by jbeale
Fri Jun 04, 2021 4:53 pm
Forum: Troubleshooting
Topic: lockup on 4b : Firmware transaction timeout ?
Replies: 25
Views: 2032

Re: lockup on 4b : Firmware transaction timeout ?

Another thing- not a lockup, but while watching a FB video, just that window stopped with an error message that it could not play the video, and I saw 'dmesg' report [80931.936571] bcm2835-codec bcm2835-codec: bcm2835_codec_buf_prepare data will not fit into plane (1536 < 1775616) [81070.586343] mma...

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