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by HermannSW
Thu Jun 20, 2019 12:51 am
Forum: General discussion
Topic: Using RasPi for multiple display outputs
Replies: 12
Views: 282

Re: Using RasPi for multiple display outputs

What I can't seem to figure out is how to use a remote command to make the monitor connected to the RPI to display an image file. Besides what others said, I like to use omxiv to view images. One reason is that its hardware accelerated and much quicker than eg. "eog" X11 image viewer. The other is,...
by HermannSW
Thu Jun 20, 2019 12:34 am
Forum: Camera board
Topic: best compromise quality/size for time-lapse camera
Replies: 8
Views: 289

Re: best compromise quality/size for time-lapse camera

and how can I detect darkness using picamera to trigger a shutdown? how do I read the image and see if most of pixels are beyond a threshold close to black? I don't use picamera, but you can use picamera Array API. For black detection you may use PiYUVArray and only look at the Y component: https:/...
by HermannSW
Wed Jun 19, 2019 9:12 am
Forum: Camera board
Topic: Review: Graspinghand gooseneck camera mount
Replies: 8
Views: 269

Re: Review: Graspinghand gooseneck camera mount

ghawkins wrote:
Wed Jun 19, 2019 7:54 am
I just ordered it direct from the GraspingHand website.
Thanks, just bought one (9.95€ plus €3.60 shipping).
by HermannSW
Tue Jun 18, 2019 9:33 pm
Forum: Camera board
Topic: Review: Graspinghand gooseneck camera mount
Replies: 8
Views: 269

Re: Review: Graspinghand gooseneck camera mount

And yes - it seems to work out well enough, I thought the "arm" might bounce about too much when the thing is in motion but it seems to be OK. Nice, but usability depends of speed of robot (and whether running on flat surface, or off road outside). For my first caterpillar robot platform I fixated ...
by HermannSW
Tue Jun 18, 2019 8:42 pm
Forum: Camera board
Topic: open discussion on the camera latency
Replies: 7
Views: 1806

Re: open discussion on the camera latency

If you have LOTS of light, then exposure time can be down at a few milliseconds. Off topic, but if you really have lots of light , then exposure time can be down to a few micro seconds. Below frame is lighted with 2×5000lm leds , and multiple exposures of 8.33µs strobe pulse length at 9kHz PWM freq...
by HermannSW
Tue Jun 18, 2019 4:14 pm
Forum: Camera board
Topic: open discussion on the camera latency
Replies: 7
Views: 1806

Re: open discussion on the camera latency

If you try to do a gstreamer streaming solution, take jitterbuffer into account: https://www.raspberrypi.org/forums/viewtopic.php?f=43&t=204921&p=1273950#p1273950 This project allows for <0.1s latency: https://github.com/131/h264-live-player I use uv4l a lot, you can stream camera as well as HDMI ou...
by HermannSW
Tue Jun 18, 2019 9:41 am
Forum: Camera board
Topic: Review: Graspinghand gooseneck camera mount
Replies: 8
Views: 269

Re: Review: Graspinghand gooseneck camera mount

and I'm surprised this kind of mount isn't more popular. I am surprised as well that I have never seen it mentioned on this forum (perhaps I just missed that) as that holder is avaibale for 5 years now. On German amazon it is currently unavailable. It's very easy to flex into any position you want ...
by HermannSW
Tue Jun 18, 2019 7:31 am
Forum: Camera board
Topic: Convert MJPEG output to mp4
Replies: 5
Views: 168

Re: Convert MJPEG output to mp4

You can put mjpeg into an mp4 container with ffmpeg -r 15 -i foo.mjpg -c:v copy bar.mp4 Thanks, this works with http mjpeg stream as well (I used wget, maybe there is a direct ffmpeg way to do so as well): $ ffmpeg -r 15 -i <(wget http://192.168.178.157:81/stream -O -) -c:v copy bar.mp4 Just termin...
by HermannSW
Mon Jun 17, 2019 3:49 pm
Forum: Camera board
Topic: Convert MJPEG output to mp4
Replies: 5
Views: 168

Re: Convert MJPEG output to mp4

I'm not sure what ffmpeg options are required to achieve this, if you have had it working would you mind sharing what options you use? I tried several of the mjpeg2mp4 solutions and none worked. Then I went back to gstreamer, and was able to readout and display mjpeg stream from ESP32-CAM module Ca...
by HermannSW
Mon Jun 17, 2019 2:41 pm
Forum: General discussion
Topic: Generate multiple PWM signals
Replies: 5
Views: 165

Re: Generate multiple PWM signals

Hi. Actually the pi can generate several software PWM signals which should all you need for speed control on an L298D if you want to drive things like servos then look at joan's pigpio library, which of course you could also use to provide PWM signals to your L298D http://abyz.me.uk/rpi/pigpio/ For...
by HermannSW
Mon Jun 17, 2019 9:08 am
Forum: Camera board
Topic: Raspberry v1 camera global (external) shutter videos
Replies: 23
Views: 2106

Re: Raspberry v1 camera global (external) shutter videos

Family was out yesterday forenoon and I used our living room for new airgun pellet captures. All window shutters in living room and that in kitchen were closed, as well as room door and room doors upstairs for real darkness. After 1 hour of setting up the scene, testing, adjustment, just before new ...
by HermannSW
Sun Jun 16, 2019 10:45 pm
Forum: Camera board
Topic: Ultra high-speed imaging, capturing matrix style bullet time.
Replies: 4
Views: 565

Re: Ultra high-speed imaging, capturing matrix style bullet time.

I am not sure whether revalo still monitors this forum, you can find the wiring description in his github repo: https://github.com/revalo/pishot#gpio-based Yes, the work of revalo's team is amazing, capturing a single point in time with many Raspberry v1 cameras. You can do amazing stuff with a sing...
by HermannSW
Sat Jun 15, 2019 9:27 pm
Forum: Camera board
Topic: Convert MJPEG output to mp4
Replies: 5
Views: 168

Re: Convert MJPEG output to mp4

ffmpeg:
https://www.google.com/search?&q=conver ... mmand+line

P.S:
Off topic, I just used ffmpeg to cut out part of twitter video, and gifenc.sh to convert to animated .gif (robot's response is nice):
https://twitter.com/HermannSW/status/11 ... 0042497024
by HermannSW
Sat Jun 15, 2019 1:17 pm
Forum: Camera board
Topic: Raspberry v1 camera global (external) shutter videos
Replies: 23
Views: 2106

Re: Raspberry v1 camera global (external) shutter videos

I did a second look at 2nd global external shutter capture of pellet a 12kHz PWM frequency. I would have expected that the pellets (there are 4× more than in 1st capture with 3kHz PWM frequency) all are located on blue line because the pellet moved very fast (109.2m/s determined by 1st global extern...
by HermannSW
Sat Jun 15, 2019 1:41 am
Forum: Camera board
Topic: Raspberry v1 camera global (external) shutter videos
Replies: 23
Views: 2106

Re: Raspberry v1 camera global (external) shutter videos

My friend proposed to shoot through a stretched piece of paper and capture the pellet with v1 camera behind the paper. Of course that will reduce pellet speed, but since the pellet will create a hole that just allows the pellet to fly through, most of the oil cloud should remain behind the paper, a...
by HermannSW
Sat Jun 15, 2019 12:49 am
Forum: Camera board
Topic: Camera dropping frames, any advice?
Replies: 16
Views: 583

Re: Camera dropping frames, any advice?

I cannot see artifacts. I played with Linux "Videos" as well as with totem video player, both times more than 9s on the incrementing time display. Then I used vlc and indeed it completes faster, and does not show an incrementing seconds display. So yes, vlc does not play this video right, use anothe...
by HermannSW
Fri Jun 14, 2019 9:27 pm
Forum: Camera board
Topic: Camera dropping frames, any advice?
Replies: 16
Views: 583

Re: Camera dropping frames, any advice?

You don't say how you play the video. When I play it it shows nearly 10s length. And ptsanalyze shows 0 frameskips, and 291 frames at 30fps, that is 9.7s: $ ptsanalyze timestamp.pts 0 creating tstamps.csv 291 frames were captured at 30fps frame delta time[us] distribution 5 33324 11 33325 49 33326 1...
by HermannSW
Fri Jun 14, 2019 3:09 pm
Forum: Camera board
Topic: picamera minimize power consumption
Replies: 2
Views: 116

Re: picamera minimize power consumption

I doubt that you can increase battery lifetime much with that, since no Pi model has any sleep modes like ESPs or Arduinos. In "1W server challenge" thread I first measured an ESP32-CAM module to use 186mA at 3.3V only: https://www.raspberrypi.org/forums/viewtopic.php?t=238870#p1461306 I was totally...
by HermannSW
Fri Jun 14, 2019 9:10 am
Forum: Camera board
Topic: Scrolling Horizontal Blur
Replies: 7
Views: 221

Re: Scrolling Horizontal Blur

That's what I get for writing the post without checking. -fli, --flicker : Set flicker avoid mode (see Notes) ... Flicker avoid mode options: off,auto,50hz,60hz Please note that if your exposure time is below the flicker period then there is nothing you can do on the camera settings. Thank you for ...
by HermannSW
Fri Jun 14, 2019 7:24 am
Forum: Camera board
Topic: Scrolling Horizontal Blur
Replies: 7
Views: 221

Re: Scrolling Horizontal Blur

If it is more, then use the -fl option to specify the mains frequency, and ae will choose exposure times that are a multiple of the flicker period. I had seen mains flicker myself in the past and was not aware how to overcome that with a raspivid option (I bought led drivers that deliver DC to the ...
by HermannSW
Fri Jun 14, 2019 6:07 am
Forum: Camera board
Topic: Scrolling Horizontal Blur
Replies: 7
Views: 221

Re: Scrolling Horizontal Blur

EZKernel wrote:
Fri Jun 14, 2019 1:58 am
as it is not synced up to my capture speed.
What is your capture speed?
What mode?
raspivid or raspistill with combining frames afterwards?
(youtube video stats for nerds says the frames are 946x532 ?!?!?)
by HermannSW
Fri Jun 14, 2019 1:10 am
Forum: Camera board
Topic: Pi 3 B+, v2.1 camera abyssmal fps @1080p
Replies: 12
Views: 381

Re: Pi 3 B+, v2.1 camera abyssmal fps @1080p

@HermannSW what is the resolution of the monitor you are testing on? is it 1080p?. Wouldn't that be 12 frames skipped for your v2 result, being that 30fps and 10 seconds should equal 300 frames or is there some other way to calculate it like the camera actually didn't record for 10 seconds? No, as ...
by HermannSW
Thu Jun 13, 2019 7:38 pm
Forum: Camera board
Topic: High framerate raspivid (initially 640x480 at 180fps)
Replies: 24
Views: 6882

Re: High framerate raspivid (initially 640x480 at 180fps)

Until now "high framerate" did mean >100fps for me (with raspivid up to 200fps, with raspiraw up to 665/1007fps for v1/v2 camera). Recently I did use "global reset" mode of ov5647 v1 sensor with an external shutter to do high eps (exposures per second) captures of fastest for now airgun pellet with ...
by HermannSW
Thu Jun 13, 2019 6:16 pm
Forum: Camera board
Topic: Pi Microscope with inverted pi lens
Replies: 4
Views: 163

Re: Pi Microscope with inverted pi lens

So 10µm/px? Or 10µm/3280px? I got best result with a 20° lens, but I had to move it more than 10cm away from the imx219 sensor on the board. To avoid light effects, I finally used an aluminum tube in a microscope holder: https://www.raspberrypi.org/forums/viewtopic.php?t=210605&start=50#p1409956 htt...
by HermannSW
Thu Jun 13, 2019 5:36 pm
Forum: Camera board
Topic: Pi Microscope with inverted pi lens
Replies: 4
Views: 163

Re: Pi Microscope with inverted pi lens

Hi, I cannot answer the technical question. Like you I did remove the original v2 camera lens, but I added a M12 lens mount instead. That allowed to use all kinds of different M12 lenses: https://www.raspberrypi.org/forums/viewtopic.php?f=43&t=45887&p=1298451#p1279957 You say 10 micron (10µm) resolu...

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