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Relay via USB serial port CP2102
Posted: Sunday 07 May 2017 14:05
by geotravel
Hello,
I have relay as attached picture and USB<->serial port base on CP2102 . Is it possible use together these devices with domoticz ?? How to create
this software switch in domoticz to switch On/OFF relay via USB serial port ??
Regards
Waldek
Re: Relay via USB serial port CP2102
Posted: Sunday 07 May 2017 17:31
by SweetPants
geotravel wrote:I have relay as attached picture and USB<->serial port base on CP2102 . Is it possible use together these devices with domoticz ?? How to create this software switch in domoticz to switch On/OFF realy via USB serial port ??
No you cannot connect the CP2102 to the Relay. The CP2102 is a serial port adapter unless it has RTS/DTR pins, then it might be possible.
Re: Relay via USB serial port CP2102
Posted: Sunday 07 May 2017 17:51
by geotravel
Hi,
As attached picture USB serial converter have output RTS (in bottom output pins). So I can connect RTS pin to IN in board relay and send
command under linux to SET HI or LOW RTS line ???
Re: Relay via USB serial port CP2102
Posted: Sunday 07 May 2017 18:08
by SweetPants
geotravel wrote:Hi,
As attached picture USB serial converter have output RTS (in bottom output pins). So I can connect RTS pin to IN in board relay and send
command under linux to SET HI or LOW RTS line ???
It's DTR/RST not RTS.
Name Pin # Type Description
...
RST 9 D I/O Device Reset. Open-drain output of internal POR or VDD monitor. An
external source can initiate a system reset by driving this pin low for
at least 15 μs.
Re: Relay via USB serial port CP2102
Posted: Sunday 07 May 2017 18:13
by SweetPants
Re: Relay via USB serial port CP2102
Posted: Sunday 07 May 2017 18:39
by geotravel
Please find attached picture where I marked green square DTR/RTS and this converter have output RTS line marked by red square
or it is mistake description on board
Re: Relay via USB serial port CP2102
Posted: Sunday 07 May 2017 19:28
by geotravel
Ok by if I have usb/serial converter with RTS line how to create bash or python script to send /dev/ttyUSB0 to set HI or LOW RTS line?
Re: Relay via USB serial port CP2102
Posted: Saturday 21 October 2017 16:00
by DoubleHP
I have published a detailed answer here:
https://forums.gentoo.org/viewtopic-p-8 ... ml#8132756
Here is the short version:
Code: Select all
#!/bin/bash
MySerialPort="/dev/ttyUSB0"
MyLatency="2"
echo "#include <fcntl.h>
#include <sys/ioctl.h>
main()
{ int fd; fd = open(\"${MySerialPort}\",O_RDWR | O_NOCTTY );
int RTS_flag; RTS_flag = TIOCM_RTS;
ioctl(fd,TIOCMBIS,&RTS_flag);
sleep (${MyLatency});
ioctl(fd,TIOCMBIC,&RTS_flag);
close(fd); } " | tcc -run -
Note that sending data on TX will probably mess RTS; see the Gentoo forum for details.