I'd like to modify LIRC to output non-modulated signal (without 36-39 kHz modulation). I'm looking at irsend.c, but fail to see the hardware control code. It must have been somewhere in lirc main files. Any hints?
In my case the solution was already in the driver. The modified driver for raspberry pi (lirc_rpi) takes a few parameters, among them softcarrier.
So if you do:
sudo modprobe lirc_rpi softcarrier=0
the carrier wave will be eliminated.
Related
I'm trying to send files over a half-duplex interface (RS-485) between a box PC running debian (4.19) and a SBC with an im6xDL.
Thanks to this community I can successfully transfer simple data between the units using picocom or by echoing/reading.
The box PC supports half-duplex RS-485 natively and has automatic RTS functions so that you can read/send data without any issue. The SBC on the other hand needs to be toggled to change into RX or TX mode.
This turned out to be a problem when I tried to send files from the box PC to the SBC.
On the box PC:
picocom /dev/ttyUSB0 -b 9600 -fn
C-a,C-S
***file: /home/user/test.txt
Transfer incomplete
*** exit status: 128
On the SBC
picocom /dev/ttymxc2 -b 9600 -fn -et
C-a,C-r
Terminal ready
�000000
As you can see something is terribly wrong, it is like it cannot interpret the bits when a file is being transferred.
My questions:
Is it possible to send files from the command line in half-duplex systems? (The SBC needs to be in RX mode the entire time).
Is there another way to achieve this that is more intuitive?
As always, thanks for the help and support :)
/W
See here:
Pymodbus - Read input register of Energy meter over rs485 on uart of raspberry pi3
The solution I presented there using pylibmodbus should work for any hardware with UART and one or two GPIO lines accessible from user space in Linux.
If, on the other hand, what you want to do is use something like picocom or minicom then you can take a look at the hardware-only solution using a 555 timer.
Of course, if prototyping circuits is not for you, you can always buy a USB to RS485 with half-duplex support. You have many available but those based on the MAX13487 IC seem to work very well.
EDIT: The solution using the 555 timer is not in the post I linked above but here together with some more background material on half-duplex RS485 links: RS485: Inappropriate ioctl for device
I am trying, and failing, to connect an I2S microphone (Invensense ICS43432) to my Raspberry Pi (B+) running Arch Linux. I have asked for specific advice in the relevant Arch Linux ARM forum but my question is really more general than that: how does one go about debugging Linux audio input issues?
I have verified with a logic analyser that the I2S microphone is sending sensible data in the correct channel (left) and the correct pin of the Raspberry Pi. The I2S microphone appears under ALSA as a "sound card". arecord is perfectly happy to record from that device and I have boosted the gain of that device using alsamixer by 30 dB. Yet all the data bytes of the recorded file are zero.
How does one go about checking the flow of audio data, the operation of DMA, under Linux?
I had the same problem trying to record in stereo, using 2 Adafruit I2S MEMS breakout mics: arecord worked fine, but zeros when using ALSA to write to a bin file. Choosing a 32 bit word format (Little Endian 32 bits, Signed) made it work. Only I end up with 64 bit stereo Frames.
I would like to know if is possible to use an MCP23017 16 bit I/O expander with a MCP3008 ADC and read the voltage with a Raspberry Pi 2. I want to use the ADC as an I2C device. I would like to do this so I don't have to run the program a 'root', so I'm thinking that running the ADC as an I2C device will fix this problem. I'm looking for help with how to wire the system as well as programming it. I'm using the Python 3 editor. The existing program I have will be used to plot a sine wave generated by a AD9850 DDS module who's signal is amplified and fed into a device. I want to measure this voltage. I know how to use a voltage divider, but am having trouble coming up with a way to read it. The measured voltage value needs to be stored as global variable that can be passed around the program. Right now I'm mainly concerned with not running the program as a root, turning the ADC into an i2c device, and storing the voltage as a global variable to be passed around in an existing program.
I have not worked with any kind of I2C TO SPI converter. Still, you can use some I2C to SPI bridges if they work, I just googled it, but that can cause wiring problems.
I can suggest you the same ADC MCP series with I2C interface.Thus, the further I2C connections with MCP23017 expander and then the Raspberry pi would be easy.You can go through various analog to digital converters that can be I2C interfaced with their codes in python or java for pi like MCP3425, MCP3426, MCP3427, MCP3428. You can easily find them or also check control everything as that would be easy to interface using I2C cables and adapters preventing connection or wiring problems.For codes: https://github.com/ControlEverythingCommunity?utf8=%E2%9C%93&query=MCP34
The following codes for MCP_23017 can also help you code the way you want easily with expander being connected to pi:https://github.com/ControlEverythingCommunity/MCP23017_16-Channel.
I think this would solve your problem!!
Thanks.
There is no interface to the piece of hardware that I'm trying to access the Serial number of, which makes it rather difficult to install new libararies. Also, memory is limited.
Any help is appreciated on how to extract serial number, thanks.
ok, it is late, but this information my help someone:
1 - if the board supports DMI:
so you might check the /sys/class/dmi directory:
Example on Kernel 3.16 (output values are modified)
~$ sudo cat /sys/class/dmi/id/board_serial
PCDIVZ33X1C320
~$ sudo cat /sys/class/dmi/id/chassis_serial
4CZ145A2S5
~$ sudo cat /sys/class/dmi/id/product_serial
4CZ145A2S5
this allows you to bypass the dmidecode programm and to write language independent programs (no en/de/fr/... output parsing).
2 - if the board documentation serve the information how to read the serial number directly:
You may be able to read e.g. the content of an onboard eeprom which holds the serial number.
this may be possible throught the /sys filesystem , too.
to see, whats possible - an Example from a HP Laptop:
cat /sys/bus/i2c/devices/*/name
Radeon i2c bit bus 0x90
card0-DP-3
Radeon i2c bit bus 0x91
Radeon i2c bit bus 0x92
Radeon i2c bit bus 0x93
Radeon i2c bit bus 0x94
Radeon i2c bit bus 0x95
Radeon i2c bit bus 0x96
Radeon i2c bit bus 0x97
card0-DP-1
card0-DP-2
sorry for this device not having an eeprom on i2c...
This looks like what you are querying is from the BIOS. The BIOS would contain a table of information about your hardware, serial numbers, etc.. this can be queried according to the SMBIOS standard. dmidecode reads this information from the table using this standard.
So alternatively, you may want to look into the standard and write code for reading the required information or serial numbers etc. or ask your hardware/firmware vendor if they have any libraries or hooks available for this purpose.
I am trying to O/P audio to a USB soundcard (Lindy PnP SoundCard device) via Python/PySide/PyQT by the use of Phonon and/or QTMultimedia.
I can O/P the aduio (mp3/wav) which is no problem - the issue is that I want to control the USB's output sample clock rate, I need to be able to change this from 44.1 to 48 kHz. The soundcard comes with its own s/w that allows this so it is possible.
I can play Audio through Phonon like so..
self.mediaObj=phonon.Phonon.MediaObject(self)
self.audioSink=Phonon.AudioOutput(Phonon.MusicCategory, self)
self.audioPath=Phonon.createPath(self.mediaObj, self.audioSink)
self.audioSink.setVolume(0.3)
However I do not see any way to change the sample clock rate of the USB device from looking at the Class Reference doc's it seems its not possible.
http://www.pyside.org/docs/pyside/PySide/phonon/index.html
So then I have tried to use Qt Multimedia to change the USB soundcards O/P clock rate..
format = QtMultimedia.QAudioFormat()
format.setChannels(2)
format.setFrequency(44100)
format.setSampleSize(16)
format.setByteOrder(QtMultimedia.QAudioFormat.LittleEndian)
format.setSampleType(QtMultimedia.QAudioFormat.SignedInt)
This has no effect. Does anyone know how I would do this and if it is even possible with Phonon/PyQT? I am guessing I need to go lower and try find the USB Soundcard directly which will be messy..
Much appeciate any help!!
Alan