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by Richard-TX
Mon Dec 29, 2014 3:01 am
Forum: General discussion
Topic: send/recieve messages between pi
Replies: 37
Views: 7109

Re: send/recieve messages between pi

For email gatewaying , I like exim as a MTA. Set up right, it does everything needed.

For experimentation with telnet based connections to ports I recommend that telnet and telnetd be installed. Once you understand how telnet and telnetd works, then adding a new listening process is easy.
by Richard-TX
Mon Dec 29, 2014 2:53 am
Forum: General discussion
Topic: send/recieve messages between pi
Replies: 37
Views: 7109

Re: send/recieve messages between pi

One of the things we used to do to remote *nix systems where we wanted custom script to run on demand was to set up a unique account on the remote machine. When we sent email to that account, the dot-forward file for that account would pass off the email to a script where it would be checked for syn...
by Richard-TX
Mon Dec 29, 2014 2:30 am
Forum: Beginners
Topic: New to Raspberry and Linux
Replies: 14
Views: 1653

Re: New to Raspberry and Linux

To cd back down the directory tree you cd into the special directory ".." which means "parent". To go to the start of the directory tree you can cd / and to go to a specific directory cd /full/path/of/directory. Other options: cd on its own takes you to your home directory which is also called "~"....
by Richard-TX
Sun Dec 28, 2014 8:14 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: RPi and internal UART [solved]
Replies: 23
Views: 3277

Re: RPi and internal UART

there is no reason at all to open and close the serial channel more than once, reopening the channel continiously is a bug in your code! you should open the channel once at the start of your program, and only close it when the program closes. Agreed, but the TX held low at open is just one of the p...
by Richard-TX
Sun Dec 28, 2014 8:08 pm
Forum: Graphics, sound and multimedia
Topic: Internet Radio, need advice
Replies: 5
Views: 1486

Re: Internet Radio, need advice

Why don't you look at some computer speakers? They have a built in amp and sound OK for what they are.
by Richard-TX
Sat Dec 27, 2014 4:03 pm
Forum: Off topic discussion
Topic: YOU SUCK: the venting thread
Replies: 948
Views: 147971

Re: YOU SUCK: the venting thread

The last time I used facebook was when I read a co-workers page. In it was: "Loaded the kids in the car. Going to Walmart. Stopping to get gas. We are now at Walmart. Doing some shopping for school supplies." I immediately nuked my facebook account and have never gone back. I do not want or need to ...
by Richard-TX
Sat Dec 27, 2014 3:57 pm
Forum: Automation, sensing and robotics
Topic: 1 Channel relay and GPIO
Replies: 13
Views: 3615

Re: 1 Channel relay and GPIO

I see a few issues, 1 - The logic behind most of those relays is active low which is the opposite of what you would expect. It is how it is designed. 2 - using that relay to control 110-220 volts is dangerous at best. You would be far better off using a UL/CE approved solid state relay. I NEVER use ...
by Richard-TX
Sat Dec 27, 2014 3:51 pm
Forum: General discussion
Topic: Detect about 40 switches: Which hardware to use?
Replies: 7
Views: 1877

Re: Detect about 40 switches: Which hardware to use?

mikronauts wrote:- use an mcp23017 on the i2c bus
+1

If you want to get fancy, use a keyboard controller IC.
http://www.ti.com/lit/ds/symlink/lm8330.pdf
by Richard-TX
Sat Dec 27, 2014 3:47 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: RPi and internal UART [solved]
Replies: 23
Views: 3277

Re: RPi and internal UART

joan wrote:TX drops low for about 32 µs on /dev/ttyAMA0 open. If you bit bang you don't have that problem.
That pretty much proves the point that the Rpi's on board UART isn't what it should be.
by Richard-TX
Sat Dec 27, 2014 3:46 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: RPi and internal UART [solved]
Replies: 23
Views: 3277

Re: RPi and internal UART

There isn't much I can do about the receiver. It is what it is.

Having said that, the issue follows the Rpi's internal uart. Use another UART like a FT232 connected to the Rpi's USB bus and no problems occur.
by Richard-TX
Sat Dec 27, 2014 3:03 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: RPi and internal UART [solved]
Replies: 23
Views: 3277

Re: RPi and internal UART

Just to give a little background on the RS232 issue, I have a Rotel receiver that only has a RS232 port for interfacing to a computer. The whole purpose of the Rpi was to monitor the CEC/HDMI data and turn on/off the receiver whenever the TV got turned on/off. It was when I put the code in a infinit...
by Richard-TX
Sat Dec 27, 2014 2:55 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: RPi and internal UART [solved]
Replies: 23
Views: 3277

Re: RPi and internal UART

@jam1 Might be worth starting a new post giving details of the serial code you are using. It's unlikely the serial link is faulty. pigpio will let you bit-bang serial data on any of the gpios on the expansion header. In my experience 19.2 kbps or less is solid. Maybe I am wrong, but If the on board...
by Richard-TX
Sat Dec 27, 2014 2:51 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: RPi and internal UART [solved]
Replies: 23
Views: 3277

Re: RPi and internal UART

In my case the code is pretty straight forward. #!/bin/bash DEV="/dev/ttyAMA0" stty 19200 < $DEV echo -n -e "\xfe\x03\xc3\x10\x4b\x21" > $DEV #echo "power on" I had to send that data about 12 times before the remote device would get a string that it would recognize. If I used the USB serial port, th...
by Richard-TX
Fri Dec 26, 2014 6:32 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: RPi and internal UART [solved]
Replies: 23
Views: 3277

RPi and internal UART [solved]

It appears that the RPI UART has some issues. The sending of a character upon open is just one. The next time I need a RS232 port, I am going to just get a USB to RS232 adapter and use that. The on-board UART is just too wonky.
by Richard-TX
Fri Dec 26, 2014 4:02 pm
Forum: Beginners
Topic: seven segment
Replies: 7
Views: 1409

Re: seven segment

The MAX chips are SPI devices. That makes them incompatable with i2c devices like the MCP23017. I believe that a BCD to 7 segment decoder (7447/7448) is actually easier to troubleshoot and use with a MCP23017. I will also make the software a breeze to write. I would use a shell script. Of course wir...
by Richard-TX
Fri Dec 26, 2014 9:21 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Fixed I2C address - best solution for third sensor
Replies: 41
Views: 5801

Re: Fixed I2C address - best solution for third sensor

Raspy already has two 1.8 K pullup resistors on SDA/SCL lines, so the two 10 K resistor could be omitted . Merry Christmas, Ale. I always add 10 k pullups at the i2c devices. Adafruit does the same thing and other engineers do as well. You do what you want. They currently have 10K Ohm and it works,...
by Richard-TX
Fri Dec 26, 2014 9:16 am
Forum: Media centres
Topic: My MPD solutiion
Replies: 6
Views: 2841

Re: My MPD solutiion

There are many client programs for MPD. The one that I use a lot is the Gnome music player client. Available for almost all platforms including windows and Linux. Hi Richard, The title of the thread might be misleading, but this is a different solution. I wrote my own server program, using Rasperry...
by Richard-TX
Thu Dec 25, 2014 11:30 pm
Forum: General discussion
Topic: Self powered serial network of 4 Pi
Replies: 4
Views: 739

Re: Self powered serial network of 4 Pi

Just because you can do something doesn't mean that you should.

I am not sure why you need 4 Rpis that close together but have you considered leveraging the I2c or SPI buses?
by Richard-TX
Thu Dec 25, 2014 11:25 pm
Forum: Python
Topic: when i add a python script to rc.local on boot failed
Replies: 2
Views: 635

Re: when i add a python script to rc.local on boot failed

redirect stderr to a file

script 2> /var/log/script.err 1> /var/log/script.out &
by Richard-TX
Thu Dec 25, 2014 11:08 pm
Forum: Other programming languages
Topic: i2c-bus - A new Node.js module for I2C
Replies: 9
Views: 6107

Re: i2c-bus - A new Node.js module for I2C

Set the I2c bus to 600kc and 1.2 mhz and lets see what that does.
by Richard-TX
Thu Dec 25, 2014 8:41 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Fixed I2C address - best solution for third sensor
Replies: 41
Views: 5801

Re: Fixed I2C address - best solution for third sensor

ilguargua wrote:Raspy already has two 1.8 K pullup resistors on SDA/SCL lines, so the two 10 K resistor could be omitted .

Merry Christmas, Ale.
I always add 10 k pullups at the i2c devices. Adafruit does the same thing and other engineers do as well.

You do what you want.
by Richard-TX
Thu Dec 25, 2014 7:00 pm
Forum: Staffroom, classroom and projects
Topic: new to raspberry pi - ages of users
Replies: 12
Views: 20761

Re: new to raspberry pi - ages of users

Age group? It depends on the intent of use. I use the Rpi as a small controller for a variety of tasks. As such I fall into the 30+ year old demographic group.
by Richard-TX
Thu Dec 25, 2014 6:56 pm
Forum: Media centres
Topic: My MPD solutiion
Replies: 6
Views: 2841

Re: My MPD solutiion

There are many client programs for MPD. The one that I use a lot is the Gnome music player client. Available for almost all platforms including windows and Linux.
by Richard-TX
Thu Dec 25, 2014 6:55 pm
Forum: Beginners
Topic: BASIC
Replies: 29
Views: 3386

Re: BASIC

When will basic die the death it so richly deserves?

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