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by andies
Thu Dec 22, 2016 10:01 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Impedance of GPIO lines
Replies: 11
Views: 7765

Re: Impedance of GPIO lines

That measurement is invalid I am sorry, I do not know enough about electronics to understand what you wrote. I did not measure any clock, I was on GPIO 27 and this was set to input. Also, what is the connection of raspberry to printed circuit board (assuming that this stands for PCB)? I do not know...
by andies
Thu Dec 22, 2016 9:57 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Impedance of GPIO lines
Replies: 11
Views: 7765

Re: Impedance of GPIO lines

Burngate wrote:As far as I can see, and assuming GPIO-27 was set as an input for your tests, you've verified that the internal pull-down resistor is close to 50k.
Is that what you intended?
Yes.
by andies
Wed Dec 21, 2016 8:16 pm
Forum: Automation, sensing and robotics
Topic: pigpio and pilight-raw
Replies: 7
Views: 2167

Re: pigpio and pilight-raw

It seems to send raw data ("noise") to output. The difference to Piscope is that Piscope gives me a picture or a movie, pilight-raw gives me the actual numbers. From the wiki (although the description is a little bit terse): pilight-raw will output raw numbers representing the time difference in µs ...
by andies
Tue Dec 20, 2016 10:06 pm
Forum: Automation, sensing and robotics
Topic: pigpio and pilight-raw
Replies: 7
Views: 2167

pigpio and pilight-raw

Is there a program similar to pilight-raw -L in the pigpio-library? I am struggling with my garage door opener and need the raw codes. I only partially understand the pilight-library, the code might be well documented but the wiki is not and many things are not well described (what is the difference...
by andies
Tue Dec 20, 2016 9:58 pm
Forum: Automation, sensing and robotics
Topic: RFSniffer - Can't get it working
Replies: 53
Views: 25870

Re: RFSniffer - Can't get it working

Does anyone have an RPi 3 working with an RF sensor? I am still trying but until now I failed (see https://www.raspberrypi.org/forums/viewtopic.php?t=164177 ): Those sensors pick up too much "noise" (in fact they show me those signal-numbers all the time without any button pressed, the reason seems...
by andies
Tue Dec 20, 2016 9:37 pm
Forum: Troubleshooting
Topic: Noise with 433MHz receiver [Completely solved]
Replies: 65
Views: 21895

Re: Noise with 433MHz receiver [Solved]

I just made a nice histogram with the numbers a simple pilight-raw -L command produces over four seconds. Interestingly, the numbers around 20 appear very often. I was not aware that any particular device (weather station, garage opener...) was sending anything during those four seconds. Noise.png O...
by andies
Tue Dec 20, 2016 4:19 pm
Forum: Troubleshooting
Topic: Noise with 433MHz receiver [Completely solved]
Replies: 65
Views: 21895

Re: Noise with 433MHz receiver [Solved]

I think I finally solved the problem. It is very embarrassing: "Somehow" parts of wiringPi got deleted. I cannot reconstruct what happened but it seems that I had two installations on my Pi. One manually installed version and another via apt-get. Then, the apt-get version was removed. In the end not...
by andies
Tue Dec 20, 2016 12:59 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Impedance of GPIO lines
Replies: 11
Views: 7765

Re: Impedance of GPIO lines

My measurements were without any frequencies.
by andies
Sun Dec 18, 2016 5:21 pm
Forum: Troubleshooting
Topic: Noise with 433MHz receiver [Completely solved]
Replies: 65
Views: 21895

Re: Noise with 433MHz receiver [Opened again]

I know, once I was searching several months (!) for a strange error until I found out that my 1A couldn't handle the current :evil:

This time I have a 2,5A supply.
by andies
Sun Dec 18, 2016 4:40 pm
Forum: Troubleshooting
Topic: Noise with 433MHz receiver [Completely solved]
Replies: 65
Views: 21895

Re: Noise with 433MHz receiver

I did some further "research" and I am starting very slowly to understand what is going on here. Maybe I will put this in another thread because in my head and even on this forum so many things were/are wrongly stated. I have measured the voltage of the 433-receiver. If no signal is present the rece...
by andies
Sun Dec 18, 2016 4:27 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Impedance of GPIO lines
Replies: 11
Views: 7765

Re: Impedance of GPIO lines

I did the following: I shortened GPIO27 to 3.3V using a resistor on a RPi3. Then I used a digital voltmeter to measure the voltage at this resistor (high impedance, BBC MA 5D). I had six resistors at hand and could measure the following voltage V depending on resistor R: resistor (kΩ) voltage (V) 0,...
by andies
Thu Dec 15, 2016 9:26 pm
Forum: Troubleshooting
Topic: Noise with 433MHz receiver [Completely solved]
Replies: 65
Views: 21895

Re: Noise with 433MHz receiver [Opened again]

Unfortunately, I have to open the thread again. For some reason I was unable to get any signal. Learned from the posts above I did the following: started sudo pigpiod and also watched PISCOPE checked gpiotest, but Tested user gpios: 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 ...
by andies
Sat Dec 10, 2016 6:21 pm
Forum: Troubleshooting
Topic: Noise with 433MHz receiver [Completely solved]
Replies: 65
Views: 21895

Re: Noise with 433MHz receiver [Solved]

I noticed that using the recoding feature of Piscope gives me three instead of two signals:

Code: Select all

2000C1FF
2800C1FF
2000C0FF


Any idea what that is?
by andies
Tue Dec 06, 2016 5:27 pm
Forum: Troubleshooting
Topic: Noise with 433MHz receiver [Completely solved]
Replies: 65
Views: 21895

Re: Noise with 433MHz receiver

To wrap up: I just checked the signal from the cheap Chinese sender using pilight-raw and received a clear and unique signal. So in the end there are two lessons learned for me: Get not the cheapest receiver (in particular, XY-MV-5 was bad for me). At least "superheterodyn" is necessary. I also need...
by andies
Tue Dec 06, 2016 5:13 pm
Forum: Troubleshooting
Topic: Noise with 433MHz receiver [Completely solved]
Replies: 65
Views: 21895

Re: Noise with 433MHz receiver

joan wrote:f there are no level changes the display will stop updating.
Again something learning, great - thank you!
by andies
Tue Dec 06, 2016 4:05 pm
Forum: Troubleshooting
Topic: Noise with 433MHz receiver [Completely solved]
Replies: 65
Views: 21895

Re: Noise with 433MHz receiver

Have you confirmed the transmitter frequency? Maybe I start with the entire story from the beginning. I have two different senders that control the garage opener (see below the picture of a very cheap copy, the original is from Came) and a somfy roller shutter (second picture). My idea was to copy ...
by andies
Tue Dec 06, 2016 1:00 pm
Forum: Troubleshooting
Topic: Noise with 433MHz receiver [Completely solved]
Replies: 65
Views: 21895

Re: Noise with 433MHz receiver

Just learned from another post: "Purpose of the filter is the reduction of interrupts and CPU load. 433 MHz transmission is based on OOK (ON-OFF-Keying) of a 433 MHz RF carrier, the result is a square signal with sharp rising/falling edges. You cannot apply any kind filter to this kind of signals, y...
by andies
Sun Dec 04, 2016 9:13 pm
Forum: Troubleshooting
Topic: Noise with 433MHz receiver [Completely solved]
Replies: 65
Views: 21895

Re: Noise with 433MHz receiver

I installed a low-pass filter (ATTiny as in the pilight forum, https://wiki.pilight.org/doku.php/low-pass_filter ) but I was not successful. I could flash the processor, wiring is ok but still there is too much noise. I enclose picture with the pilight-raw signal received with the same superheterody...
by andies
Sun Nov 27, 2016 8:17 pm
Forum: Troubleshooting
Topic: Noise with 433MHz receiver [Completely solved]
Replies: 65
Views: 21895

Re: Noise with 433MHz receiver

Using the above I am now able to look at all time length that are 500mico-sec and above using (I was not able to formulate a more elegant code)

Code: Select all

sudo pilight-raw | sed -n -e 's/433gpio: //p' | sed -n -e '/[5-9][0-9]\{2,4\}/p'
Still a lot.
by andies
Sun Nov 27, 2016 12:11 pm
Forum: Troubleshooting
Topic: Noise with 433MHz receiver [Completely solved]
Replies: 65
Views: 21895

Re: Noise with 433MHz receiver

New approach. I installed pilight to observe the noise. It turned out that my XY-MV-5 receiver is not able to distinguish between noise and the signal from my garage opener. Therefore, this receiver is useless for me. I turned to the RBX12. There, I do see something (see above) but I am not able to...
by andies
Sat Nov 26, 2016 2:52 pm
Forum: Troubleshooting
Topic: Noise with 433MHz receiver [Completely solved]
Replies: 65
Views: 21895

Re: Noise with 433MHz receiver

maybe it is not Manchester? As far as I understand it there must to be only two "pulse-length" if it is Manchester decoded. Irrespective whether it is 00, 01, 10 or 11 only one short and one long pulselength is possible (see https://www.youtube.com/watch?v=XKtxxZ327UM ). But I have several length. H...
by andies
Sat Nov 26, 2016 2:38 pm
Forum: Troubleshooting
Topic: Noise with 433MHz receiver [Completely solved]
Replies: 65
Views: 21895

Re: Noise with 433MHz receiver

Maybe I have to correct myself again. I removed the resistor (joan told me...) and indeed got a signal that is more informative than the one above. See the screenshot below. There are some symmetries in there, but how come that this cannot be decoded? I am pretty sure this is Manchester. I also meas...
by andies
Sat Nov 26, 2016 12:49 pm
Forum: Troubleshooting
Topic: Noise with 433MHz receiver [Completely solved]
Replies: 65
Views: 21895

Re: Noise with 433MHz receiver

I managed to get a bit further. What I found out using piscope was that there is a lot of noise coming in (we had this before, but at that time it came from actually installing rpimonitor using the same port - rpimonitor is not installed this time). I then lowered the noise using pigs fg 27 300 and ...
by andies
Thu Nov 24, 2016 6:08 pm
Forum: Troubleshooting
Topic: Noise with 433MHz receiver [Completely solved]
Replies: 65
Views: 21895

Re: Noise with 433MHz receiver

I managed to get a signal using a 38k resistor as pull-up, I checked several resistors and this seemed to be the best. Below is a sketch of my construction, also a picture of the signal (using piscope). Unfortunately, neither sudo ./RFSniffer nor sudo ./_433D r2 will give me any code. Any idea what ...

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