Matt Little’s workshop on Off-grid solar PV @ EMFCamp 2014

Matt Little and a Solarcooker

Matt Little and a Solar cooker

One of the workshops at EMF Camp was Matt Little’s workshop on off grid solar Photo Voltaic, however due to being stuck in traffic I was unable to attend it. as some one intrested in off grid living (being on a boat and all)

After the fact I spoke to Matt via twitter and he sent me the link to the course material, and said that he would be holding his next work shop in Bristol, which I will not be able to make.
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Doctor Who’s K9

K.9 and company titles

K.9 and company titles

For a very long time, I have been planning on making a RC K-9 from the BBCs Doctor Who, recently I aquired a copy of “K9 and Company: A Girl’s Best Friend”

K-9 and Company was a proposed television spin-off of the original programme run of Doctor Who (1963–1989). It was to feature former series regulars Sarah Jane Smith, an investigative journalist played by Elisabeth Sladen, and K-9, a robotic dog. Both characters had been companions of the Fourth Doctor, but they had not appeared together before. A single episode, “A Girl’s Best Friend”, was produced as a pilot for a proposed programme, but was not taken up. “A Girl’s Best Friend” was broadcast by BBC1 as a Christmas special on 28 December 1981.

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Ethernet, RS485 and power down a single cat 5 cable

For my boat automation system I plan to use RJ45 sockets and cat 5 cable for interconnecting the master and the nodes.

Some nodes will have their own 12 V supply for larger loads, but ones that are just for switches and other transducers (sensors) will need to have 12 V delivered to them. According to the cat5 specification the cores are AWG 24, which means that it has a nominal maximum current carrying capacity of about 0.5 A (short term peak 3.5 A).

Ethernet 10/100 uses only 4 cores. 1,2,3, and 6. This leaves 4,5,7 and 8 free for other things (because of the way the cable is wired those are both 2 pairs of twisted cable, so no sharing of twisted pairs either).
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HACman hits EMF 2014

Eagle and PCB design with Matt Venn

webGerberAt Wuthering Bytes in Hebden Bridge, in the afternoon Tas and I attended Matt Venn‘s Eagle cad workshop, if we had been there all day we would have made a Shrimp board.

But since I have been using eagle a littlebit, and am far from any good with it, we sat in in the afternoon, (I used his github as the base for my node circuit).

I did some more work on my RS485 Ardiuino Node PCB.

Tas and I went to the Wurthering Bytes tech festival with Manchester space program, however due to administritive errors that didn’t go ahead.
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Other Websites

For a while I have been looking after, and running other websites, these three make for new additions to my portfolio:

  • Biscuit – for girls who like girls and boys
  • FreedomNews – The new news site for Freedom Press
  • FreedomPress – An online store front for the Freedom Book Shop

I hope that I can pick up some more work for my portfoilo soon.

RS485 R-Pi to Arduino

I found the following code extracts for the Arduino (I have a Diavolino) to work with the RS485 shield from here:

Code for the transmitter:

void setup()
{
        Serial.begin(115200);
}
 
void loop()
{
    Serial.println ("hello RX_Test");
    delay(1000);
}

Code for the receiver:

String mydata = "";
 
void setup()
{
    Serial.begin(115200);
}
 
void loop()
{
    while (Serial.available() > 0)  
    {
        mydata += char(Serial.read());
<!--more-->

        delay(2);
    }
    if (mydata.length() > 0)
    {
        Serial.print(mydata);
        mydata = "";
    }
}

And a guide for the R-Pi shield (from here).

Putting the two together (I don’t have two Arduinos and shields) so using the R-Pi and the Arduino, with the R-Pi set to be master, and the R-Pi as a slave,

I have carried out the two changes to the R-Pi config from here, and installed minicom (Bob is helping).

sudo apt-get install minicom
minicom -s
F - Turn off flow control
A - /dev/ttyAMA0
E - 115200 8N1

Wire the R-Pi and the Arduino together

Raspbery Pi and Arduino connected via RS485

Raspbery Pi and Arduino connected via RS485 (note the RS485 connections).

Using both Arduino Sketches above, you can get two way coms from the Arduino (via the Serial Monitor) to the Raspberry Pi:

Set up for long distance communcations…

Set up for long distance communcations… of about 300mm


to exit from Minicom Ctrl+A, then Q

Building a Diavolino

On Saturday I picked up an Evil Mad Scientists Arduino clone, The Diavolino, from MadLab‘s little shop “Invent-ory” to use with my RS485 stuff. the Diavolino requires assembly yourself (official instructions).

The FTDI I bought was this one: RHX PL2303 USB To RS232 They are about £2.29 per. however where Windows 7 will grab the drivers from Windows Updates, there is a little bit more work to get it to be happy on a mac:
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RS485 on Arduino

Arduinon RS485 GPIO Shield

Arduinon RS485 GPIO Shield

Following on from the RS485 on an Raspbery Pi post, I also picked up a LinkSprite RS485 Arduino board from RoboSavvy (Arduino RS485 schematics).

I plan on trying to get the two to talk to each other, using a short bit of three cores:

  • A aka ‘-‘ aka TxD-/RxD- aka inverting pin
  • B aka ‘+’ aka TxD+/RxD+ aka non-inverting pin
  • Gnd

I plan on trying to set up a Master / Slave relationship with the Raspbery Pi being the master, and the Arduinos the slaves (Full arduinos will be replaced with Shrimps or equiv and a Max481CSA).

Project Wonderful

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