Show Posts
Pages: 1 ... 420 421 [422] 423 424 ... 580
6316  Using Arduino / Project Guidance / Re: ArdweeNET - simple and robust networking for monitoring and control on: July 05, 2011, 09:52:57 am
I guess the design is bang on then so I've started PCB layouts.

Here's a quad +-20A sensor node.



Approx lifesize (on my screen anyway), should be 40mm wide.



This one is larger than standard because of the relatively huge connectors needed for 20 amps.

Bear in mind that this is effectively a tiny Duemilanove that is dedicated to reading current and telling the world the results via RS-485.
 
______
Rob

6317  Community / Products and Services / Re: New product: Digit Shield on: July 05, 2011, 09:00:55 am
Hi Michael,

Love your boards.

I'm working on a 4-digit board myself at present (not a shield so no competition), there's something very satisfying about getting LEDs to work, much more so than LCDs smiley

______
Rob
6318  Using Arduino / Networking, Protocols, and Devices / Re: serial com port communication with Mega on: July 05, 2011, 05:53:22 am
Quote
The netbook is using simple serial communication.
Does this means it's NOT using USB?

Quote
But when I connect it to the netbook and change the com port to 4
It won't necessarily be on the same port with a different computer.


______
Rob
6319  Using Arduino / General Electronics / Re: RS232 shield on: July 05, 2011, 05:49:39 am
have a look at shieldlist.org

______
Rob
6320  Using Arduino / General Electronics / Re: beginner question about connecting two components.. on: July 04, 2011, 09:39:58 pm
The 3.3v TX output from the IMU will "probably" work if fed directly to the AVR RX input. (anything over 2.5-3v should be seen as a logic high)

The IMU may have "5v tolerant" inputs, if so you can feed the AVR TX directly to the IMU RX. (check the data sheet)

If not you can use two resistors as a voltage divider to reduce the AVR 5v to 3.3.

______
Rob
6321  Topics / Home Automation and Networked Objects / Re: Starting an Home Automation project on: July 04, 2011, 09:29:08 pm
Quote
a relay is used to turn on / off lights, isn't it?
Often a relay is a good choice yes.

Quote
And if I'm not wrong I can also check if the relay is turned on or off.
Use a double-pole relay and use the spare pole to read the relay status, or keep a variable in RAM that tells you what the current state is.

Quote
Where can I found an example code about it?
DigitalWrite (relayPin, HIGH); should about do it.

Quote
how can I control the power of the light to make them more ligher or less?
I assume we're talking AC mains. Normally a Triac can be used to adjust the brightness. It can also be used to turn on/off the light so in this case it's a better choice than a relay.

However, a normal triac is not isolated from the mains (that's bad) but you can get opto-isolated versions that are or just use an opto-coupler.

Quote
I can use relay but I don't understand if it's a standard eletronic component or if I need to build one like this:
You need to do as the PDF says or something equivalent. But that's not "building a relay", it's just controlling one.

Quote
How can I develop and manage them? What do I need to do that (the elettronic parts). Are there some "already made" (something that is developed for arduino) parts to use?
You need to develop a "network" of some kind. Given the number of times we get asked this I'm surprised nobody is ever interested in posts about new networks smiley, maybe there's already too many around.

______
Rob

 

6322  Using Arduino / Programming Questions / Re: Need to understand Serial-RS485 master/slave addressing on: July 04, 2011, 08:55:32 pm
Here's a hint

D  = CR
A  = LF
6D = m
65 = e
73 = s
73 = s
61 = a
67 = g
65 = e
20 = SPACE
73 = s
65 = e
6E = n
74 = t

I don't know what send/receiveMSG() does (can't find the source at that link) but I doubt you can use it on the same port at the same time as Serial.print/receive().
______
Rob
6323  Using Arduino / Installation & Troubleshooting / Re: Arduino versus LabJack on: July 04, 2011, 10:26:47 am
Quote
is it possible to trigger (external 20 Hz signal) the arduino?
Is it possible to send instructions to the arduino?
Is the arduino able to execute the instructions during the 20 Hz stream?

Yes to all the above.

______
Rob
6324  Using Arduino / LEDs and Multiplexing / Re: Multiplexing 90 analog inputs on: July 04, 2011, 06:42:41 am
How will you measure resistance? You will need another 90 resistors to form 90 voltage dividers I would think.

Quote
will the arduino have a delay of more than 2 sec to complete all recording and comparing of arrays?
It should be much faster than that. The actual readings might take about 25uS max I think, add some for the program and you're well under 2secs.

You will need analogue muxes, 6 4067s or 12 4051s.
______
Rob

6325  Using Arduino / General Electronics / Re: beginner question about connecting two components.. on: July 04, 2011, 06:36:13 am
Quote
the Uno just has inputs labelled Tx and Rx also
It does but they are also connected to the USB chip and this usually causes problems.

Quote
to connect it to the mega
The Mega has inputs labeled TX1,2,3 and RX1,2,3, just pick a matching pair (say 1) and

Serial1.begin(115200)
Serial1.available() etc etc

Quote
to connect it to the mega to use those values on the fly
Don't know what this means. What is "it".

Quote
on both chips?
What's the second chip? If you mean the IMU then yes, just connect IMU Tx to the Mega RXn and IMU Rx to Mega Txn.

______
Rob
 



 
6326  Using Arduino / Project Guidance / ArdweeNET - simple and robust networking for monitoring and control on: July 04, 2011, 12:05:49 am
For the last couple of weeks I've been working on the design of a simple (from the application programmer's point of view) async network for monitoring and control applications.

Yes, another one smiley However I'm pretty sure that this is different in many ways. Basically it's a poor-man's low-speed cross between Ethernet and CAN.

It uses an ATtiny84 as the network interface, this handles most of the bush clash and synchronizing issues. There's code also running on the application processor but this doesn't have a lot to do so in general the application is free to read sensors or do whatever it does.

Basic features are

  • Open design, no royalties, licensing fees or costs for intellectual property. Creative Commons and/or GNU licenses will apply.
  • Only implements a low-level transport layer similar to the OSI layers 1 and 2.
  • Implements a "publishing and subscribing" model, nodes publish at will and subscribers act on the published data.
  • Multi-master with non-destructive collision detection.
  • Wide supply voltage, VBAT can range between 7 and 30 volts.
  • Very fault-tolerant physical level (uses RS-485 transceivers).
  • High level of error detection (relative to the intended applications) for reliability, including packet-level CRC and watchdog ICs.
  • Rogue applications on nodes cannot kill the bus.
  • Six-wire flat telephone cable and RJ12 6/6 modular jacks. Wiring includes power and data signals.
  • Four-wire (RJ11) and 8-wire (RJ45) cables/jacks can also be used.
  • Plug in backwards immune. Power and data auto adjust.
  • Flexible wiring topology, “anything goes”.
  • Uses off-the-shelf standard electronic components.
  • Bit rates from 2400 to 115200 with auto-bit rate detection.
  • Standard node size is 40x40mm, however a node can be implemented with as little as 6 components and fit on a PCB approx. 12mm square or even smaller.
  • Nodes can be neatly daisy-chained.
  • Use the processor of your choice; AVR, PIC, Picaxe, ARM, 8051 etc

Here is a 3D graphic of a typical node.




Note that these are essentially cut-down Duemilanoves with built-in RS-485 so they can be used with your own networking code if that's preferable.

There is a small range of these being designed right now, things like RTC, accelerometer, current and voltage measuring inputs, relay outputs, temperature inputs, LCD and LED displays, USB interface etc.

And the network interface looks like this



If you've got this far then I guess you are at least mildly interested so have a look at my site for some more information

http://ardweenet.robgray.com/

And if you're really interested there's a design document (still a work in progress)

http://ardweenet.robgray.com/documentation/docs/ArdweeNET-overview-v0-1.pdf

RFC (Request for Comment)
I'm about to start PCB designs so this is a good time to ask the knowledgeable folk here for comments. Of particular interest to me are major stuff ups, is there anything here that just won't work? But of course all ideas are welcome.

So if you have any thoughts either post here or email me.

Thanks for your time guys.

_____
Rob





6327  Topics / Home Automation and Networked Objects / Re: Using Arduino with C Bus on: July 03, 2011, 10:59:58 pm
C-bus is designed and pushed by Clipsal

http://www.clipsal.com/

However for the life of me I can't find their download page so I've copied some files to my site.

www.robgray.com/temp/C-Bus Applications.pdf
www.robgray.com/temp/C-Bus Interface Requirements.pdf
www.robgray.com/temp/C-Bus Quick Start Guide.pdf
www.robgray.com/temp/C-Bus Serial Interface User Guide.pdf

There's a lot of info there so knock yourself out.

I don't know much about this particular protocol, I just collect this kind of data because I'm interested in monitoring and control networks.

EDIT: Just found a Clipsal site that might have more info

http://www2.clipsal.com/cis/technical/


______
Rob
6328  Using Arduino / Project Guidance / Re: Would love feedback on first solo code for project on: July 03, 2011, 08:37:02 pm
Code:
pinMode(vccPin, OUTPUT); digitalWrite(vccPin, HIGH);
  pinMode(gndPin, OUTPUT); digitalWrite(gndPin, LOW);

Are you powering the MAX chip from IO pins?

If so it's a novel approach and should work as the chip only draws about 1mA but it's a little strange.

______
Rob
6329  Topics / Home Automation and Networked Objects / Re: Using Arduino with C Bus on: July 03, 2011, 08:20:31 pm
AFAIK c-bus works with "normal" serial data at 300-9600 bps with 9600 being the recommended speed.

It's a full ISO 7 layer protocol which seems something of an overkill.

Despite me having what appears to be a comprehensive set of documentation PDFs I'm buggered if I can see what the PHY layer is.

Quote
C-Bus supports a number of interfaces such as RS232 and TCP/IP
These of course are two totally different and non-comparable things so that's not much help.

Quote
cable lengths up to 1000 meter using Cat-5 cable
This implies RS-485, no way RS-232 will do this.


Anyway if you can figure out how to connect to the PHY layer it should be easy to sniff the data with a serial port, the protocol is well documented.

______
Rob
6330  Using Arduino / Interfacing w/ Software on the Computer / Re: Another Arduino VB Serial question. on: July 03, 2011, 07:08:02 pm
Serial.print doesn't send a CRLF, does my_SerialPort.ReadLine expect a CRLF before it returns a "line"? If so use Serial.println().

Quote
its does not transmit data
How do you know? You can't trust the VB prog yet so how do you know the Arduino is not transmitting?

______
Rob
 
Pages: 1 ... 420 421 [422] 423 424 ... 580