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by jbeale
Mon Jul 15, 2019 5:48 am
Forum: General discussion
Topic: Simple Infra-Red record/playback
Replies: 56
Views: 9929

Re: Simple Infra-Red record/playback

As far as sending the signal three times, it turns out that some kinds of lighting, eg. LEDs with PWM dimming, compact fluorescent and maybe gas-discharge lights, can have high frequency noise that may have a frequency similar to a valid IR code, in addition to other nearby IR controls for other dev...
by jbeale
Mon Jul 15, 2019 5:37 am
Forum: General discussion
Topic: Hardware Encoder in Raspberry pi 4B
Replies: 7
Views: 678

Re: Hardware Encoder in Raspberry pi 4B

If you are using the official Raspberry Pi camera, the raspivid application does hardware encode to H.264 on all previous models of Pi, and I presume continues to do so on the Pi 4. https://www.raspberrypi.org/documentation/usage/camera/raspicam/raspivid.md If you want to transcode some other video ...
by jbeale
Mon Jul 15, 2019 3:25 am
Forum: General discussion
Topic: Pi 4 PCB Defect? (fiberglass thread loose)
Replies: 15
Views: 1298

Re: Pi 4 PCB Defect?

If you're talking about 0:47 I see along the top edge what may be a sliver of FR4 or whatever PCB board material they are using, I would assume due to a slightly rough cut when they separated that specific board from the larger panel during manufacturing. When you layout a board you have to follow d...
by jbeale
Sun Jul 14, 2019 5:24 am
Forum: Troubleshooting
Topic: Raspberry pi 4 is injecting noise into audio circuit
Replies: 3
Views: 194

Re: Raspberry pi 4 is injecting noise into audio circuit

I'm not sure I would say the Pi4 is injecting noise. Unless the noise is actually on the digital bitstream (which it isn't, if the volume doesn't affect it), the Pi cannot be the source of it all by itself, which the experiment with the HDMI cable confirmed. I would say you have an analog voltage no...
by jbeale
Sun Jul 14, 2019 1:50 am
Forum: General discussion
Topic: Want to measure battery volts
Replies: 38
Views: 1786

Re: Want to measure battery volts

If you are not comfortable with electronic design, I do not recommend working with +48V from a high-current source (anything strong enough to run a refrigerator probably qualifies). Accidentally shorting out a power supply like that could be rather spectacular in a not-so-good way. It may seem too b...
by jbeale
Sat Jul 13, 2019 2:35 pm
Forum: General discussion
Topic: ffmpeg to record 30 FPS video from 2M camera
Replies: 2
Views: 169

Re: ffmpeg to record 30 FPS video from 2M camera

You don't mention which version of the Pi you have (Original Pi, Pi2, Pi3, Pi4)? Any of them are capable of handling the raw data rate of a compressed 1080p mp4 video just as a file transfer, but I believe that actually encoding such a video in real time at 30 fps requires the GPU hardware. At least...
by jbeale
Sat Jul 13, 2019 3:54 am
Forum: General discussion
Topic: Pi 4 heat sinks
Replies: 21
Views: 2758

Re: Pi 4 heat sinks

The purpose of a heatsink compound is to fill in small gaps, such as between the SoC and the HS. If you've got two bare metal surfaces, they will not be in good physical and thermal contact (unless they are optically flat) without something to fill in around the tiny bumps from surface roughness, li...
by jbeale
Wed Jul 10, 2019 10:19 pm
Forum: Beginners
Topic: Is it a true ground?
Replies: 5
Views: 262

Re: Is it a true ground?

I would be willing to bet all the RPi boards use a single shared ground net. HOWEVER, between any two points on the circuit board that are nominally "ground" there is a finite, non-zero resistance. If you pass significant current through any part of the R-Pi board, you are responsible for the local ...
by jbeale
Wed Jul 10, 2019 5:21 pm
Forum: Camera board
Topic: Record video stream continuously / autoremoving the oldest ones
Replies: 4
Views: 311

Re: Record video stream continuously / autoremoving the oldest ones

One more thought: "BlueCherry" is a complete Linux DVR solution and includes exactly the functions you describe, among others. I have used it for 24/7 video recording and it works fine, BUT I have not tried to run it on a Raspberry Pi, or with the Pi camera. I believe the typical use case takes vide...
by jbeale
Wed Jul 10, 2019 5:07 pm
Forum: Camera board
Topic: Record video stream continuously / autoremoving the oldest ones
Replies: 4
Views: 311

Re: Record video stream continuously / autoremoving the oldest ones

PiKrellCam does this with motion-triggered video. https://billw2.github.io/pikrellcam/pikrellcam.html It also has a mode to do time-lapse, and manually triggered recording. It is pretty configurable and can probably do continuous video segments too, although I haven't tried that. It also has a scrip...
by jbeale
Wed Jul 10, 2019 5:41 am
Forum: For sale
Topic: Raspberry Pi 4B in USA
Replies: 28
Views: 4665

Re: Raspberry Pi 4B in USA

the us power supply is the hotter item to get , with out it your new pi4 will not work properly as it has a usb-c special circuit. To clarify: current Pi4 boards do not work with so-called "e-marked" USB-C cables (eg. Apple cables), but it does work with at least some other USB-C cables, and USB-C ...
by jbeale
Mon Jul 08, 2019 11:28 pm
Forum: Advanced users
Topic: RaspberryPi 4: heatsink or fan
Replies: 50
Views: 20579

Re: RaspberryPi 4: heatsink or fan

Personally I like the fanless solution for what I suspect is better long-term reliability, when I'm putting Pi boards into possibly dusty places that are hard to get to.
Vault-Mess1.jpg
underground pi
Vault-Mess1.jpg (55.56 KiB) Viewed 2681 times
by jbeale
Mon Jul 08, 2019 9:50 pm
Forum: Advanced users
Topic: RaspberryPi 4: heatsink or fan
Replies: 50
Views: 20579

Re: RaspberryPi 4: heatsink or fan

I have one of those "radiator protection case" heatsink fins shown on ebay, but for a 3B. It works pretty well as a fanless heatsink, although the provided screws are *juuust* barely long enough to reach through to the opposite piece, I got maybe 1-1/4 threads of engagement and it felt like it would...
by jbeale
Mon Jul 08, 2019 2:14 am
Forum: General discussion
Topic: Is starting with a 3B+ a bad idea now that the 4b is out?
Replies: 21
Views: 1052

Re: Is starting with a 3B+ a bad idea now that the 4b is out?

For starting with a coding project and/or learning what the Pi is all about, really any model will do! The latest ones are basically just faster. I have a bunch of different Model 2 and Model 3 Pi boards doing different things (mostly measurements, also a security camera). They still do the job I wa...
by jbeale
Sun Jul 07, 2019 8:20 pm
Forum: Beginners
Topic: Project plan: cistern level monitor and control
Replies: 16
Views: 538

Re: Project plan: cistern level monitor and control

Very interesting to read of your experiments! Looks like you've done some pretty good reliability testing. I was interested given that three of the reviewers on Amazon said they had found this product unreliable, where it would get stuck either on or off. I wonder if they had mechanical fouling of s...
by jbeale
Sat Jul 06, 2019 2:12 am
Forum: Troubleshooting
Topic: random numbering of two USB audio devices
Replies: 5
Views: 199

Re: random numbering of two USB audio devices

I gather what's going on is that there are actually three audio devices on my Pi, counting the built-in PWM audio output, and apparently the "card number" of each audio device is in order of detection, but that is random per boot. When I ask 'arecord -l' which INPUT devices exist, there are only two...
by jbeale
Fri Jul 05, 2019 9:48 pm
Forum: Troubleshooting
Topic: random numbering of two USB audio devices
Replies: 5
Views: 199

random numbering of two USB audio devices

This seems mysterious to me. I have a Pi Model 3B which has two USB-Audio devices connected to it (a C-Media and a Realtek). The audio card numbering of these is not consistent across reboots. Note they are not simply swapping places: first they are numbered (1,2) but after reboot they become (0,1) ...
by jbeale
Thu Jul 04, 2019 6:53 pm
Forum: Troubleshooting
Topic: Y usb cable for power?
Replies: 9
Views: 286

Re: Y usb cable for power?

When the lightning bolt appears sometimes (meaning low voltage detected on the Pi) it means either a cheap USB cable with too high resistance (smaller wires with less copper are cheaper) or a not-good-enough power supply. Not all power supplies deliver what the label says they should, especially les...
by jbeale
Thu Jul 04, 2019 2:59 pm
Forum: General discussion
Topic: Turning on multiple devices in my room via raspberry pi
Replies: 3
Views: 136

Re: Turning on multiple devices in my room via raspberry pi

You don't need to or want to deal directly with line voltage. There are wifi controlled power switches like this to do the job for you safely: https://www.amazon.com/TP-Link-Required-Control-Anywhere-HS100/dp/B0178IC734 I have not tried it but here is an article showing how to control the TP Link HS...
by jbeale
Thu Jul 04, 2019 2:28 pm
Forum: General discussion
Topic: Adding second camera to Rpi 3?
Replies: 14
Views: 540

Re: Adding second camera to Rpi 3?

Add a second pi? Even the Pi Zero supports a camera, and the price is minimal. This gives you the freedom to position anywhere you want, instead of needing a long camera cable. You can have a command sent over the LAN trigger the photo on the second unit. Programs like PiKrellCam http://billw2.githu...
by jbeale
Thu Jul 04, 2019 2:19 pm
Forum: General discussion
Topic: Does the Pi 4 support wake on lan (wol)?
Replies: 3
Views: 879

Re: Does the Pi 4 support wake on lan (wol)?

The blog post introducing the device includes comments, where many questions are asked and answered including this one.
https://www.raspberrypi.org/blog/raspbe ... nt-1510076
by jbeale
Thu Jul 04, 2019 6:08 am
Forum: General discussion
Topic: Serial number or individual identification number for pi 4
Replies: 7
Views: 317

Re: Serial number or individual identification number for pi 4

You could use the Ethernet or the Wifi MAC address: cat /sys/class/net/eth0/address cat /sys/class/net/wlan0/address Each MAC address is only 6 bytes and the first few are fixed vendor bytes. Due to the sheer number of millions of RPi made, I don't think this number is guaranteed unique in the world...
by jbeale
Thu Jul 04, 2019 3:22 am
Forum: General discussion
Topic: Pi 4 firmware, software stability improvements
Replies: 83
Views: 18009

Re: Pi 4 firmware, software stability improvements

I wonder if the USB 3 port can be improved to work at full speed since it doesn’t allow the full or regular performance of the USB 3 port, Is this a theoretical or a practical question? The hardware connection in the Pi4 between the USB3 chip and the SoC is a single lane PCIe Gen2. It runs at 4Gbit...
by jbeale
Thu Jul 04, 2019 12:57 am
Forum: General discussion
Topic: Brand new to Raspberry Pi because of the PI4B?
Replies: 18
Views: 791

Re: Brand new to Raspberry Pi because of the PI4B?

4gig model is the new hot commodity!!! Some people are getting $150 plus one ebay for the 4gig version! Anything "buzzy" and also in short supply gets run up in price, but that sounds like evidence the Pi folks have done something right! I have a bunch of Pi boards plus a few Intel-based MiniPC uni...
by jbeale
Wed Jul 03, 2019 11:26 pm
Forum: General discussion
Topic: Linux froze and got back working 5 days later, no reboot.
Replies: 3
Views: 175

Re: Linux froze and got back working 5 days later, no reboot.

It may be possible for a voltage brown-out to lower the voltage just enough to prevent a wifi module or other USB device from working, while not actually resetting the computer itself. Any chance the 5V supply to the Pi is not entirely stable, or there are other loads which can drag it down?

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