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by HermannSW
Wed Sep 18, 2019 3:30 pm
Forum: Automation, sensing and robotics
Topic: Q on outrunner motor RPM KV relation
Replies: 1
Views: 74

Q on outrunner motor RPM KV relation

In this posting I did run a KV2700 outrunner motor with 11.9V at 4.09A with a Simonk 30A ESC, and measured "only" 4082rpm with reflective material on blade and laser tachometer: https://www.raspberrypi.org/forums/viewtopic.php?f=43&t=234416&p=1444155#p1443533 From: https://www.rotordronepro.com/unde...
by HermannSW
Wed Sep 18, 2019 2:39 pm
Forum: Camera board
Topic: raspberry pi zero w no camera preview on tv out pin (composit)
Replies: 8
Views: 252

Re: raspberry pi zero w no camera preview on tv out pin (composit)

..., but it would help if you could identify roughly where/when. - Backup your SD card in case things go bad - Use "sudo rpi-update" to update your Stretch install to the latest firmware and kernel. - Reboot. - Does that fail? If it does then use "sudo rpi-update <hash>" where <hash> is a commit ID...
by HermannSW
Tue Sep 17, 2019 12:11 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Maximum length of ethernet cable between Raspberry Pi and camera
Replies: 8
Views: 236

Re: Maximum length of ethernet cable between Raspberry Pi and camera

As Jamesh stated and 6by9 always does as well, there are no guarantees for anything longer than 15cm flex cables due to possible signal issues. But I use 1m and 2m long flex cables for years now in addition to the 15cm ones without issues. I also have flex cable extenders that allow to connect flex ...
by HermannSW
Mon Sep 16, 2019 11:57 pm
Forum: General discussion
Topic: How often I can make a photo on RPi 4B 1GB RAM
Replies: 3
Views: 134

Re: How often I can make a photo on RPi 4B 1GB RAM

v2 camera can do 3280×2464 at up to 15fps in mode 3:
https://www.raspberrypi.org/documentati ... /camera.md

It depends on the complexity of the scene you record, whether the created h264 stream can be written to your HDD or exceeds write bandwidth.
by HermannSW
Mon Sep 16, 2019 11:48 pm
Forum: Camera board
Topic: HDR images
Replies: 5
Views: 173

Re: HDR images

For static scenes your method is definitely preferable. Just wanted to mention that you can even do multiple exposure filming with Raspberry cameras:
https://www.raspberrypi.org/forums/view ... 4#p1313054
by HermannSW
Mon Sep 16, 2019 4:12 pm
Forum: C/C++
Topic: pigpio C sub µs single pulse generation
Replies: 37
Views: 3219

Re: pigpio C sub µs single pulse generation

Because currently I have Pi2B connected (before it was Pi3B+ and Pi3B) I did redo the freeze experiments with microphone sensor first (same microphone sensor). It took much more shots (magazine removed) to trigger Pi freeze (>20). I was able to freeze 2 times, the 2nd time with 100Msps logic analyze...
by HermannSW
Mon Sep 16, 2019 7:41 am
Forum: Camera board
Topic: Picture in Picture camera feed
Replies: 8
Views: 2124

Re: Picture in Picture camera feed

Hi did you completed the task? Interesting, I tried and it was easy (I play local video, playing stream is possible as well). In three consoles I executed these three commands: raspivid -t 0 -md 1 -p 22,50,960,540 omxplayer --layer=3 --win 22,50,662,530 male.3x3.sparks.h264 raspi2png This is screen...
by HermannSW
Sun Sep 15, 2019 8:54 pm
Forum: C/C++
Topic: pigpio C sub µs single pulse generation
Replies: 37
Views: 3219

Re: pigpio C sub µs single pulse generation

I'd guess this is an electrical problem. I don't think so. Sorry for answering late, I had to complete work of creating my first 20000fps video, clean and commit the tools as well as github README.md on how to do that. What you are missing is to connect "something" to GPIO13 as I described. Without...
by HermannSW
Sun Sep 15, 2019 8:08 pm
Forum: Camera board
Topic: Raspberry v1 camera global (external) shutter videos
Replies: 40
Views: 4550

Re: Raspberry v1 camera global (external) shutter videos

This posting is on how 20000fps videos got created based on the black propeller on black circular disk cardboard setup. I did update github repo README.md with all the details: https://github.com/Hermann-SW/Raspberry_v1_camera_global_external_shutter First I painted another (this time white) propell...
by HermannSW
Sun Sep 15, 2019 1:51 pm
Forum: General discussion
Topic: Laptop speakers with Raspberry PI
Replies: 25
Views: 555

Re: Laptop speakers with Raspberry PI

And are there no amplifiers in nature that can be used without soldiering? :D You can do without soldering -- I used breadboard cables and bended where needed. That works, but is not very stable, so finally you might want to solder. I used this 0.50$ amplifier (with different microcontroller): http...
by HermannSW
Sun Sep 15, 2019 10:12 am
Forum: General discussion
Topic: Cheapest High speed camera up to 900 FPS!!
Replies: 32
Views: 34032

Re: Cheapest High speed camera up to 900 FPS!!

A lot has happened since my last posting, you can find in the updated github repo: https://github.com/Hermann-SW/Raspberry_v1_camera_global_external_shutter I even captured an airgun pellet separately, but only on small part of the 2MP frame. The right image is 1:1 taken from a 2MP frame captured (f...
by HermannSW
Fri Sep 13, 2019 10:02 pm
Forum: Camera board
Topic: v2 camera can capture 1000fps videos ...
Replies: 35
Views: 10203

Re: v2 camera can capture 1000fps videos ...

1007fps is maximal Raspberry v2 camera framerate with raspiraw. That is not the maximal framerate with Raspberry cameras, but for v2 camera. Only v1 camera has global reset feature and allows for global (external) shutter capturing. In this posting it is described how a 20000eps frame (exposures per...
by HermannSW
Fri Sep 13, 2019 11:51 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: enc28j60 on pi Zero
Replies: 10
Views: 6784

Re: enc28j60 on pi Zero

DougieLawson wrote:
Thu Sep 12, 2019 7:26 pm
... (100 times slower than the gigabit ethernet on RPi3B or 4B) ...
Not true for Pi3B.
  • Pi4B 1Gbps
  • Pi3B+ 300Mbps
  • Pi3B 100Mbps
  • Pi2B 100Mbps
  • enc28j60 10Mbps
So only 10× less throughput with enc28j60 compared with Pi2B OP asked for, not sure about latency.
by HermannSW
Fri Sep 13, 2019 9:34 am
Forum: Camera board
Topic: Raspberry Pi NoIR Camera V2 no longer working!
Replies: 4
Views: 151

Re: Raspberry Pi NoIR Camera V2 no longer working!

What is output of this command?

Code: Select all

vcgencmd get_camera

You can run one of these commands to get an endless camera preview on connected monitor/display:

Code: Select all

raspistill -t 0
raspivid -t 0
by HermannSW
Wed Sep 11, 2019 8:13 am
Forum: C/C++
Topic: Do I need a special C library to turn a single stepper 180?
Replies: 3
Views: 145

Re: Do I need a special C library to turn a single stepper 180?

From Joan's link C section , these three have "readable" code, I would prefer those: WiringPi bcm2835 library pigpio I did not know of bcm2835 library, used WiringPi and pigpio (Joan's library) before. Since I needed to send out special waves with µs resolution I switched to using pigpio completely....
by HermannSW
Tue Sep 10, 2019 4:10 pm
Forum: Camera board
Topic: Raspberry v1 camera global (external) shutter videos
Replies: 40
Views: 4550

Re: Raspberry v1 camera global (external) shutter videos

Today's posting is on first 20000eps frame captured (exposures per second). The frame with most exposures per second sofar was 9000eps frame of airgun pellet. Because pellet length is 8mm, and distance between pellet exposure points is 10.77mm, flash PWM frequency cannot be increased much without ge...
by HermannSW
Mon Sep 09, 2019 4:32 pm
Forum: Camera board
Topic: Raspberry v1 camera global (external) shutter videos
Replies: 40
Views: 4550

Re: Raspberry v1 camera global (external) shutter videos

Raspberry v1 camera (clone) can do global shutter capturing at DAYLIGHT! No "external" shutter needed, but better to use external shutter for better frame quality. I have seen it before with another camera. ov2640 sensor was able to do global shutter capturing of mini drone propeller at daylight: ht...
by HermannSW
Mon Sep 09, 2019 11:09 am
Forum: Camera board
Topic: raspiraw does not connect to camera
Replies: 3
Views: 124

Re: raspiraw does not connect to camera

"gpio: not found" -- you need to install wiringpi library.
Find a complete list on what you need to install in Robert's blog posting:
https://blog.robertelder.org/recording- ... pi-camera/
by HermannSW
Sun Sep 08, 2019 10:10 pm
Forum: C/C++
Topic: pigpio C sub µs single pulse generation
Replies: 37
Views: 3219

Re: pigpio C sub µs single pulse generation

I disconnected D0 from GPIO17, and connected GPIO18 to GPIO17. In one ssh console I executed this command: $ while true; do sudo ./audio_shots.freeze 20 18 2500 2510; done It took some tries, but this is first "freeze the Pi" without microphone sensor used -- still with GPIO13 connected to Mosfets: ...
by HermannSW
Sun Sep 08, 2019 9:32 pm
Forum: C/C++
Topic: pigpio C sub µs single pulse generation
Replies: 37
Views: 3219

Re: pigpio C sub µs single pulse generation

I did 9 shots after having connected logic analyzer to freeze the Pi again: https://stamm-wilbrandt.de/en/forum/microphone.9shots.png This is zoom into 9th shot for microphone sensor D0 line: https://stamm-wilbrandt.de/en/forum/microphone.9shots.zoom.png But it does not reflect the details, I export...
by HermannSW
Sun Sep 08, 2019 9:06 pm
Forum: C/C++
Topic: pigpio C sub µs single pulse generation
Replies: 37
Views: 3219

Re: pigpio C sub µs single pulse generation

Sorry, I had too much interesting new stuff to do over the weekend in the other thread, really amazing! https://www.raspberrypi.org/forums/viewtopic.php?f=43&t=241418&p=1532876#p1532362 Now I compiled audio_shots.freeze.c, started this command and recreated Pi freeze after 5 shots (without magazine)...
by HermannSW
Sun Sep 08, 2019 4:39 pm
Forum: Camera board
Topic: Raspberry v1 camera global (external) shutter videos
Replies: 40
Views: 4550

Re: Raspberry v1 camera global (external) shutter videos

Combining spin and two speeds investigation, I did only put one blue dot onto three pellets. I filled the magazine with 2 normal pellets, then the three pellets with a single blue dot, and finally a normal pellet. After starting raspivid_ges in one console, I started this command in another console:...
by HermannSW
Sun Sep 08, 2019 4:32 pm
Forum: Camera board
Topic: How to zoom Rpi camera v2 ?
Replies: 4
Views: 251

Re: How to zoom Rpi camera v2 ?

Please see the video in the posting I pointed to, it kept at 640x480 resolution the whole time while camera moving and zooming. So your 720p resolution will not change by using camera.zoom().
by HermannSW
Sat Sep 07, 2019 9:10 pm
Forum: Camera board
Topic: Raspberry v1 camera global (external) shutter videos
Replies: 40
Views: 4550

Re: Raspberry v1 camera global (external) shutter videos

I wanted to see pellet multiple exposures with two speeds in a frame. Pellet needs to collide with something, in order to remove energy and speed. I used a long slightly slated lath for that. I determined where the pellet would need to hit the lath to be in middle of horizontal camera view and marke...
by HermannSW
Sat Sep 07, 2019 2:14 pm
Forum: Camera board
Topic: Raspberry v1 camera global (external) shutter videos
Replies: 40
Views: 4550

Re: Raspberry v1 camera global (external) shutter videos

I went back to the frame that proved fast spinning of airsoft pistol pellet during flight, and created a "fast camera panning" tool to highlight that: https://github.com/Hermann-SW/Raspberry_v1_camera_global_external_shutter#user-content-camera_panning In Sound trigger section the pellet capture wit...

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