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by HermannSW
Fri Jan 06, 2017 10:36 am
Forum: General discussion
Topic: Pi Zero hardware PWM precision
Replies: 15
Views: 5043

Re: Pi Zero hardware PMW precision

Gnerating 125MHz signal seems to be clean as well, but for measuring this cleanly more than 400Msps are needed: https://stamm-wilbrandt.de/en/forum/125MHz.png The repeating period pattern is "...|10.0, 7.5, 7.5, 7.5, 7.5|..." which corresponds to 125MHz: $ cut -f3 -d\; pwm_test.csv | sort -u 10.0 ns...
by HermannSW
Fri Jan 06, 2017 9:52 am
Forum: General discussion
Topic: Pi Zero hardware PWM precision
Replies: 15
Views: 5043

Re: Pi Zero hardware PMW precision

Yes, 50MHz signal looks clean. If I read pigpiod reference correctly, 200MHz should be possible: http://abyz.co.uk/rpi/pigpio/ I took 1M samples @400Msps several times and on two different Pi Zeros just to be sure. I found no way to save period and duty cycle in a single file, these two files are a ...
by HermannSW
Tue Dec 27, 2016 7:38 pm
Forum: General discussion
Topic: Pi Zero hardware PWM precision
Replies: 15
Views: 5043

Re: Pi Zero hardware PMW precision

I got that 400Msps logic analyzer as christmas present, nice! I used Pi Zero again to play with it: https://pbs.twimg.com/media/C0nDX5uW8AALZRG.jpg Downloading the DSLogic Ubuntu software and following the build+install instructions just worked. Sampling at 200Msps looked good, but with 400Msps I sa...
by HermannSW
Tue Dec 20, 2016 10:48 am
Forum: General discussion
Topic: How many Pi;s are dead?
Replies: 19
Views: 3033

Re: How many Pi;s are dead?

None of my 4 Pi Zeros is dead sofar, although one lost its activity indicator LED in 1st week (but it works fine, just without any visible sign of activity). I did power Pi Zero via USB2UART incorrectly with 5V (before heaving learned how to do that correctly, 3.3V UART with separate 5V cable ), but...
by HermannSW
Fri Dec 16, 2016 10:39 pm
Forum: General discussion
Topic: send email using raspberry pi in c
Replies: 12
Views: 2767

Re: send email using raspberry pi in c

> Are you running postfix (or some other MTA) on your Raspberry?
>
postfix -- as I said I did "sudo apt install postfix".
by HermannSW
Fri Dec 16, 2016 7:31 pm
Forum: General discussion
Topic: send email using raspberry pi in c
Replies: 12
Views: 2767

Re: send email using raspberry pi in c

Connecting to target server port 25 does not work always, and on my Pi Zero there was no service listening on port 25 listed by "nmap 127.0.0.1". So I did a quick search and found http://www.postfix.org/ . Installed that by sudo apt install postfix and chose "Internet" style and my system name as do...
by HermannSW
Tue Dec 13, 2016 10:06 pm
Forum: General discussion
Topic: 5MP OV5647 sensor allows for [email protected] – raspivid not
Replies: 2
Views: 824

5MP OV5647 sensor allows for [email protected] – raspivid not

I was able to record a [email protected] video with Raspberry Pi 5MP camera: raspivid -h 320 -w 240 -fps 90 -t 17000 -o video.h264 Same command with 90fps replaced by 120fps results in a [email protected] video as well. So raspivid is able to take 320x240 videos, but caps at 90fps. Is there any trick availa...
by HermannSW
Tue Dec 13, 2016 9:39 pm
Forum: General discussion
Topic: What is ili9341 refresh rate? (memory mapped framebuffer)
Replies: 1
Views: 935

What is ili9341 refresh rate? (memory mapped framebuffer)

I wrote a quick and dirty clock with 10s, 1s, 0.1s, 0.01s, and 0.001s display. I based the code on this sample code: http://raspberrycompote.blogspot.de/2013/01/low-level-graphics-on-raspberry-pi-part_22.html I tested that a new block is written first and then the old one is removed. The update time...
by HermannSW
Mon Dec 05, 2016 5:29 pm
Forum: General discussion
Topic: 2 Displays through RPI?
Replies: 3
Views: 881

Re: 2 Displays through RPI?

Just use two identical displays, and connect both.
If not enough power, one display may be darker than the other:
Image

Hermann.
by HermannSW
Sat Nov 19, 2016 3:50 pm
Forum: General discussion
Topic: Zero usb dongle??
Replies: 38
Views: 5048

Re: Zero usb dongle??

> ping raspberrypi.local > On some Linux it does work for me, on some it does not. My Cable modem router is 192.168.178.1 I use "ping -sn 192.168.178.1/24" to list all devices connected in our house, including the Pi Zero: $ nmap -sn 192.168.178.1/24 Starting Nmap 5.51 ( http://nmap.org ) at 2016-11...
by HermannSW
Thu Oct 20, 2016 7:34 pm
Forum: General discussion
Topic: Pi Zero remote controlling quadcopter using 3 USB webcams?
Replies: 2
Views: 923

Re: Pi Zero remote controlling quadcopter using 3 USB webcam

10$ quadrocopter arrived in 16 days, and its fast ... (prod spec: 30km/h)
https://www.youtube.com/watch?v=sEW9FoqCzRQ
Image

Hermann.
by HermannSW
Tue Oct 11, 2016 1:06 am
Forum: General discussion
Topic: Pi Zero hardware PWM precision
Replies: 15
Views: 5043

Re: Pi Zero hardware PMW precision

> but going to 200MHz jumps to >250$ minimal price even on aliexpress
>
Not true anymore, have not bought this, but you can get 400Msps for 70$ (only):
https://www.aliexpress.com/wholesale?ca ... c+analyzer

Hermann.
by HermannSW
Sat Oct 08, 2016 9:11 pm
Forum: General discussion
Topic: vnc connection error
Replies: 15
Views: 10409

Re: vnc connection error

What does Pi VNC server log show when you cannot connect?
by HermannSW
Sat Oct 08, 2016 8:37 pm
Forum: General discussion
Topic: Schematics of Raspberry Pi Zero
Replies: 35
Views: 28707

Re: Schematics of Raspberry Pi Zero

Yesterday I did use 1 Lipo only for powering. Today I used 4 of them with buck step down converter to 5V to power Pi Zero: https://stamm-wilbrandt.de/en/forum/IMG_20161008_221716.jpg It started with 16.72V(4.98V) and stopped after 20 minutes. Remaining voltage was 15.98V, so this could run much long...
by HermannSW
Sat Oct 08, 2016 2:58 pm
Forum: General discussion
Topic: Will Rpi price go down thanks to weaker Pound?
Replies: 16
Views: 6754

Re: Will Rpi price go down thanks to weaker Pound?

Its probably not the RPi you are interested, but the Pi Zero does cost 4£(5$), the same amount as shipping (to Germany). There is not much price difference to be expected ;-)
by HermannSW
Fri Oct 07, 2016 11:25 pm
Forum: General discussion
Topic: How do I show Emoji?
Replies: 21
Views: 5369

Re: How do I show Emoji?

If you ssh into Pi Zero, you can simply show emoji if your OS you use to ssh into Pi Zero can. Just "shift+u1f680enter" or "shift+u1f683enter" as shown below: https://stamm-wilbrandt.de/en/forum/pi.emoji.png My Linux shell command prompt is dangerous at least in some places. If I post on some forums...
by HermannSW
Fri Oct 07, 2016 7:43 pm
Forum: General discussion
Topic: Schematics of Raspberry Pi Zero
Replies: 35
Views: 28707

Re: Schematics of Raspberry Pi Zero

Thanks for the confirmation,

Hermann.

P.S: I just powered Pi Zero streaming USB webcam to 320x240 LCD over 5V/GND pins from a single 150mAh 30C Lipo (4.2V loaded) for 13:30min! Measuring Lipo after that shows 3.9V left.
Image
by HermannSW
Fri Oct 07, 2016 4:21 pm
Forum: General discussion
Topic: Schematics of Raspberry Pi Zero
Replies: 35
Views: 28707

Re: Schematics of Raspberry Pi Zero

there is a mystery U13 location, no idea yet what its for, seems to be a SOT23-6 device. There are also several other unpopulated resistors (or maybe capacitors). I suspect it's for a USB current-limiting chip. In lieu of it, there's a zero Ohm resistor directly linking PWR IN to the OTG port Does ...
by HermannSW
Wed Oct 05, 2016 9:03 pm
Forum: General discussion
Topic: Pi Zero remote controlling quadcopter using 3 USB webcams?
Replies: 2
Views: 923

Re: Pi Zero remote controlling quadcopter using 3 USB webcam

Indeed two webcams placed as described are enough for precise quadcopter 3D location detrmination. But the webcam on the wall needs to take two polar coordinates into account (z and x) like the ceiling webcam (y and x). The two pictures will define two half-lines originating at each webcam's lense, ...
by HermannSW
Tue Oct 04, 2016 11:30 pm
Forum: General discussion
Topic: Pi Zero remote controlling quadcopter using 3 USB webcams?
Replies: 2
Views: 923

Pi Zero remote controlling quadcopter using 3 USB webcams?

Today I ordered a 10$ mini quadcopter: https://www.aliexpress.com/item/Mini-Drone-ET-NONO-2-4G-RC-Toys-4CH-6Axis-MiNi-Quadcopter-RC-Pocket-Helicopters/32734972570.html https://pbs.twimg.com/media/Ct9fsYYW8AA9Xz4.jpg Of course I do not expect it to be able to carry any additional load. Is it realisti...
by HermannSW
Sat Oct 01, 2016 9:23 pm
Forum: General discussion
Topic: Howto: Pi Zero streams USB webcam to TFT LCD with gstreamer
Replies: 7
Views: 7023

Re: Howto: Pi Zero streams USB webcam to TFT LCD with gstrea

Perhaps here is the place to describe what was the reason for getting gstreamer with USB webcam working. I wanted to create a robot that should be competitive in line following competitions. This is the winner video from a line following competition in 2013: https://www.youtube.com/watch?v=cvkveIf2o...
by HermannSW
Sat Oct 01, 2016 2:16 pm
Forum: General discussion
Topic: Howto: Pi Zero streams USB webcam to TFT LCD with gstreamer
Replies: 7
Views: 7023

Re: Howto: Pi Zero streams USB webcam to TFT LCD with gstrea

gstreamer (3/3) OK, now the final details for Pi Zero only streaming. The USB webcam only needed to be forced to 320x240, then direct display of USB webcam video stream on TFT LCD framebuffer was possible with Pi Zero -- without udp src/sink and without jpeg encode/decode. Setup is Pi Zero, powerin...
by HermannSW
Sat Oct 01, 2016 2:01 pm
Forum: General discussion
Topic: Howto: Pi Zero streams USB webcam to TFT LCD with gstreamer
Replies: 7
Views: 7023

Re: Howto: Pi Zero streams USB webcam to TFT LCD with gstrea

gstreamer (2/3) While fswebcam worked fine with the 2$ USB webcam on Pi Zero, I had problems to use it with gstreamer on Pi Zero. There was no problem to use that camera with gstreamer on Nanopi Neo. And so I did split the setup, Nanopi Neo with USB webcam streams over UDP to Pi Zero with TFT LCD. ...
by HermannSW
Sat Oct 01, 2016 1:52 pm
Forum: General discussion
Topic: Howto: Pi Zero streams USB webcam to TFT LCD with gstreamer
Replies: 7
Views: 7023

Re: Howto: Pi Zero streams USB webcam to TFT LCD with gstrea

gstreamer (1/3) I knew that gstreamer provides "fbdevsink", exactly what I needed for TFT LCD. The minimal gstreamer sample always is to use "videotestsrc". It gives picture old people knew from TV that did not send 24h a day ;-) This is the gstreamer pipeline that does show video stream with minim...
by HermannSW
Sat Oct 01, 2016 1:45 pm
Forum: General discussion
Topic: Howto: Pi Zero streams USB webcam to TFT LCD with gstreamer
Replies: 7
Views: 7023

Re: Howto: Pi Zero streams USB webcam to TFT LCD with gstrea

fswebcam gstreamer is really complex set of tools, and so I wanted to start with a quick win. I did compile "fswebcam" for Pi Zero that allowed me to capture images from USB webcam (as PNG or JPEG). I just did a bash while loop that took a photo with fswebcam and then I converted that photo with av...

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