[beagleboard] Re: trying to learn enough to get started
Sounds like you need some EE courses with control theory ;) Since you are controlling a greenhouse with a considerable amount of wiring, it sounds like your relays and A/D will be far from your main controller (BBB). Light to medium duty mechanical relays need 12VDC and a relay driver, heavy duty relays require 110VAC. If the controlled devices are far (more than a few feet) you have to worry about voltage drops across the wiring, especially if the control signals are bridging the distance (ie the relay is near the controlled device). Some sort of distributed control might be in order. By that I mean an Arduino like micro (there are a couple of small compatible boards out there) controlling one or several relays on command from the BBB and reporting status back, over serial (RS485 is multi-drop) or wireless like Zigbee. Relays are open loop type devices, there is no built-in feedback to know they have closed, usually one just assumes they closed within the time they specify. An interrupt on closing would have to be an added circuit, do you really need it? Hmm, you don't say if you are using mechanical or Solid State relays. If there are Capes with relays, I would expect they would have an external power input. Make sure to pay attention to the power required to size your supply. www.controlanything.com has been making relay control boards for years, starting with RS232 and migrating to USB, Zigbee, and now ethernet/wifi. They may not be what you want, but they have some good application and usage notes. If you are controlling heavy loads you have to worry about noise feedback. I would start by making a block diagram of the setup, then listing all the devices controlled and monitored and their requirements (current, voltage, distance from the main controller, etc). Don't forget about enclosures. Greenhouses are pretty humid, damp and electronics does NOT like moisture. It sounds like you have an interesting and challenging project. I hope this helps, Jonathan On Saturday, September 6, 2014 7:33:29 PM UTC-4, ccrisle...@gmail.com wrote: The original question was one of hardware. I can figure out the software based on what I know and feel comfortable with. My question is: how do I control roughly 20 relays, some that I need to set and some that I need to 'read', ideally as an interrupt when they close? I also need to work with a couple of A/D inputs, mainly temperature. From the documentation that I have seen, no cape can support that many relays, so I need multiple capes. How do I do that? Can they be stacked? Can I use I2C to select the address to 'write' to in order to energise the relay coil? How do I organize them to allow I2C to select an address through multiple capes? How do I get the power to drive a relay? TTL logic can't do that. These are my fundamental questions. Where can I go to get the answers? I really want to learn rather than be handed answers. I can deal with the software issues well enough, it is the hardware decisions that are stumping me. On Wednesday, September 3, 2014 10:24:01 PM UTC-4, ccrisle...@gmail.com wrote: I have a significant project that I want to accomplish this fall/winter. I would like to build a digital controller for my greenhouse. I have been a software engineer for 35 years so the programming will be easy. I don't have any experience with microprocessors and need to learn so that I can do. What introductory and intermediate sources of information would people recommend? I am thinking about a BBB running Ubuntu but am open to suggestions. Thank you, Chuck Crisler -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups BeagleBoard group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[beagleboard] Re: Getting comms going on UART1
Hi, Not and expert here, but I did manage to get communication with a device connected to UART1. What do you have connected? If there is nothing there your transmit data will just go off into space. To see data come back you would have to have a device in loopback mode, or at least the Tx connected to the Rx. I am running the Debian image, and used the ADAFRUIT-UART2 overlay. It shows up as ttyo1 (thats oh one, not zero one). I have a Sparkfun MAX3232 module that translates the 3V TTL to RS232 which goes to a little micro that responds to commands like /sh/s and returns some text. I use screen to type the text commands until I get my C program working on the BBB, or try javascript. Oh, there are also two Zigbee modules in between the micro and the BBB creating a wireless RS232 link. Hope this helps, Jonathan On Monday, September 22, 2014 12:35:56 PM UTC-4, Julian Gold wrote: Oh, my board revision is B6. On Monday, 22 September 2014 17:34:44 UTC+1, Julian Gold wrote: I've been struggling to get serial comms going on UART1. I have enabled it by creating a service that performs echo BB-UART1 /sys/devices/bone_capemgr.9/slots and lo! the device /dev/ttyO1 appears. However, with two terminal windows open, doing 'cat /dev/ttyO1' in one and 'echo wibble /dev/ttyO1' in the other results in nothing at all appearing in the cat window. I've tried several combinations of baud rates and flow control, with no success. What am I missing? -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups BeagleBoard group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[beagleboard] Re: How to use UART Serial Port Using BoneScript Library
I tried to use this example to write to a device I have connected to serial
port /dev/ttyO1. I know the device answers because I can use screen and
get responses. My code to send out /sh/s is:
var b = require('bonescript');
var cmd = '/sh/s';
var port = '/dev/ttyO1';
var options = {
baudrate: 9600
};
b.serialOpen(port, options, onSerial);
b.serialWrite(port, cmd);
function onSerial(x) {
if (x.err) {
console.log('***ERROR*** ' + JSON.stringify(x));
}
if (x.event == 'open') {
console.log('***OPENED***');
}
if (x.event == 'data') {
console.log(String(x.data));
}
}
I get the following response:
debian@beaglebone:~/nodews$ node shedrd.js
/usr/local/lib/node_modules/bonescript/my.js:55
var slotRegex = new RegExp('\\d+(?=\\s*:.*,bs.*' + pin.key +
')',
^
TypeError: Cannot read property 'key' of undefined
at Object.exports.load_dt
(/usr/local/lib/node_modules/bonescript/my.js:55:67)
at Object.newFunction [as serialOpen]
(/usr/local/lib/node_modules/bonescript/my.js:228:25)
at Object.anonymous (/home/debian/nodews/shedrd.js:8:3)
at Module._compile (module.js:456:26)
at Object.Module._extensions..js (module.js:474:10)
at Module.load (module.js:356:32)
at Function.Module._load (module.js:312:12)
at Function.Module.runMain (module.js:497:10)
at startup (node.js:119:16)
at node.js:902:3
debian@beaglebone:~/nodews$
Thanks for the help
Jonathan
On Monday, April 7, 2014 1:13:13 PM UTC-4, Jason Kridner wrote:
On Thursday, March 27, 2014 4:59:00 PM UTC-4, Mark A. Yoder wrote:
Nick:
I have some bonescript code that works with the UART, but I'm not using
the built-in bonescript calls. It works fine with a GPS, though I don't use
it to transmit.
I took would like to see an example that uses the bonescript calls.
I haven't had a chance to try it out as I don't have a device easy to
wire-up until later today, but can you try out this live in-a-webpage
example at: http://jsfiddle.net/jkridner/AjnJs/
Before ruing the code you need to:
beagle# *npm install -g serialport*
BoneScript simply uses this same library, so using BoneScript avoids
needing to install it.
beagle# *echo BB-UART4 /sys/devices/bone_capemgr.*/slots*
BoneScript loads this same overlay for you.
A basic listening example would be:
var b = require('bonescript');
var port = '/dev/ttyO4';
var options = {
baudrate: 115200
};
b.serialOpen(port, options, onSerial);
function onSerial(x) {
if (x.err) {
console.log('***ERROR*** ' + JSON.stringify(x));
}
if (x.event == 'open') {
console.log('***OPENED***');
}
if (x.event == 'data') {
console.log(String(x.data));
}
}
To write, you'd do:
b.serialWrite(port, data);
Hopefully you'll see some value in the simplicity.
--Mark
#!/usr/bin/env node
// From: https://github.com/voodootikigod/node-serialport
// From: https://github.com/jamesp/node-nmea
var b = require('bonescript');
var nmea = require('nmea');
//console.log(b.serialOpen);
//var sp = b.serialOpen('/dev/ttyO4', {baudrate: 9600} );
// parser: b.serialParsers.readline(\n)});
var serialport = require(serialport);
var SerialPort = serialport.SerialPort; // localize object constructor
var sp = new SerialPort(/dev/ttyO4, {
parser: serialport.parsers.readline(\n)
});
sp.on(data, function (data) {
console.log(here: +data);
console.log(nmea.parse(data));
});
On Thursday, December 19, 2013 1:49:30 AM UTC-5, Nick Farrell wrote:
I am a newbie to BeagleBone Black(BBB) but have good knowledge about
Arduino. I would like to know how to open a serial port in BBB using the 4
UARTs available in BBB using BoneScript library and use cloud9 ide to see
the serial data on the console. Can anyone help me on this issue.
--
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[beagleboard] BBB Debian Distribution Web Page Questions
Hello, I have a BeagleBone Black running the Debian distribution. I am looking at the web page setup and the interface with node.js in preparation to set up my own web page that will display some information that I am reading over a serial port. It appears that Apache is running as the web server as I see apache2 processes. I understand that node.js can be its own web server, so I am a little perplexed why apache is used in addition to node.js and how node.js works with apache. I also don't see the web pages in the normal /var/www/ location and am wondering where they are located. Thanks -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups BeagleBoard group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
