No supported device

[merbanan]

No supported device

[Batilan]

Hi Powslang,

rtl433 is based on rtlsdr software (see http://sdr.osmocom.org/trac/wiki/rtl-sdr). This software is specific for receivers based on the Realtek RTL2832U chip, typically DVB-T dongles. These devices can be used for many more purposes than just receiving 433 MHz signals. They can be obtained cheap (less then $ 10). I got mine from ebay for $ 8.82 including shipping cost! (Seller ynaan, but others provide similar devices).

It works perfectly. It seems the small USB dongles (less then 2x2 cm) are more sensitive than the larger ones. The above mentioned one uses a R820T tuner. Before that I experimented with a Hauppauge PCTV Sports DVB-T (76e) with Fitipower FC0013 tuner which doesn't seem to be as sensitive for the 433 band . I couldn't even receive any 433 MHz signals with the transmitter placed wihin a few meters from the antenna. (also when using it to receive ADSB signals from planes I could receive packets from planes over 100 miles away using the standard antenna inside on the ground floor while the FC0013 based tuner dongle could only receive planes up to a distance of 15 miles)

Actually I think this is not a valid issue on the rtl_433 software, unless the developers think they can support other devices like your's with this sofware (probably once sampled data from the receiver is available it might be possible to use the existing code for doing the "decoding" work) but I'm not an rtl_433 expert (yet;-).

[merbanan]

433mhz rx/TX chip on breadboard is not supported, yet.

[tonyfitzs]

Hi there I am trying to get rtl_433 working with my RTL R820T clone SDR, but I am getting lots of odd errors and I can’t work out what I’m doing wrong. My Linux skills are not great so that is compounding things.
First off, I have tested my SDR using SDRConsole, and I can tune up to all kinds of fun things I am able to successfully tune to 433.965 mhz and I can hear my two motion sensors chirping away happily when triggered, I can also tune to 433.986 Mhz and can hear a door sensor as well. So I am confident there is noting wrong with my SDR device and I know that my sensors are working.
I have been following this tutorial https://guti.in/posts/2020-07-11-rtl-sdr-rpi-influxdb-temperature-monitoring/ and I am able to successfully install the RTL-SDR and rtl_433 components.

When I attempt to run rtl_433 as per the instructions, I get the following startup message.

rtl_433 version 20.02-144-g3fc80d4 branch master at 202009051935 inputs file rtl_tcp RTL-SDR
Use -h for usage help and see https://triq.org/ for documentation.
Trying conf file at "rtl_433.conf"...
Trying conf file at "/home/pi/.config/rtl_433/rtl_433.conf"...
Trying conf file at "/usr/local/etc/rtl_433/rtl_433.conf"...
Trying conf file at "/etc/rtl_433/rtl_433.conf"...
Registered 137 out of 166 device decoding protocols [ 1-4 8 11-12 15-17 19-21 23 25-26 29-36 38-60 63 67-71 73-100 102-105 108-116 119 121 124-128 130-149 151-161 163-166 ]
Detached kernel driver
Found Rafael Micro R820T tuner
r82xx_write: i2c wr failed=-1 reg=0c len=1
r82xx_init: failed=-1
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
Exact sample rate is: 250000.000414 Hz
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
r82xx_write: i2c wr failed=-1 reg=0a len=1
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
WARNING: Failed to set sample rate.
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
r82xx_write: i2c wr failed=-1 reg=05 len=1
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
WARNING: Failed to enable automatic gain.
rtlsdr_write_reg failed with -1
rtlsdr_write_reg failed with -1
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
r82xx_write: i2c wr failed=-1 reg=17 len=1
r82xx_set_freq: failed=-1
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
WARNING: Failed to set center freq.
Sample buffer too short!

The “Sample buffer too short!” repeats itself 20 or 30 time ( the screen buffer runs out so I can’t tell exactly), then I get the following

Sample buffer too short!
Async read stalled, exiting!

LIBUSB_ERROR_NOT_FOUND: Entity not found!
Check your RTL-SDR dongle, USB cables, and power supply.

WARNING: async read failed (-5).
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
rtlsdr_demod_write_reg failed with -1
rtlsdr_demod_read_reg failed with -1
rtlsdr_write_reg failed with -1
Reattaching kernel driver failed!__

So it seems clear that the USB device is not connected or is disconnecting as a result of the buffer error…. when I issue the command lsusb then I confirm this is true, however, if I disconnect the radio and then reconnect it again I can see the following when I issue the lsusb command again

Bus 001 Device 027: ID 0bda:2838 Realtek Semiconductor Corp. RTL2838 DVB-T

If I again try issuing rtl_433 I get the exact same error as shown above. I have spent many hours trying to work this out but have not had any success, is it possible to get some guidance as to what is going wrong?

[zuckschwerdt]

This is unrelated to the topic, a new issue would have been appropriate. That's not an error with rtl_433, e.g. rtl_sdr wouldn't work either I guess. Looks like something is interfering, did you forget to remove/blacklist the DVB drivers? (try lsmod to check)

[tonyfitzs]

Hi Christian, thanks for the replay. my humble appologies, I had several different pages open and I pasted the error into the wrong one sorry. if it helps I am happy to post this to the corect page.

you have mentioned about blacklisting the DVB drivers! i have not seen any referaance to anything I have read that says I need to do that, so this might be the issue. I am trying to go back a few steps and see if I can use different approch to getting this working. i.e trying to see if I can find a native Linux tool that I can use to test things before going to the rtl_433. i found this tutorial https://sdr-setup-notes.readthedocs.io/en/latest/about.html so I will try this now and loop back around if I need to. you can close this issue as I will open it in the corect place if I need to. thanks

[zuckschwerdt]

Yes, the steps for removing the DVB TV modules are listed there https://sdr-setup-notes.readthedocs.io/en/latest/dev_rtlsdr.html -- you might need to reboot, and you can check if the modules are loaded (and thus blocking access) by using lsmod and looking for "dvb" or "rtl" lines. Generally you don't want "dvb_usb_rtl28xxu" to be loaded. You should be able to unload that with just rmmod -v dvb_usb_rtl28xxu
Btw, rtl_433 and rt_sdr use the same mechanism to operate the RTL-SDR, so either should work. I don't know of any "native" tool.

[tonyfitzs]

thanks very much for your help