Perhaps the hardest part was getting this screenshot. I got it using the Android SDK ddms tool, which took some hitting with a virtual Stillson wrench to get going. If, on OS X, the command adb devices returns a blank list, you will need to add the Nook’s USB vendor ID to the ~/.android/adb_usb.ini config file. Stop the server (adb kill-server), then enter the following command:
echo 0x2080 >> ~/.android/adb_usb.ini
then restart the adb server (adb start-server). adb devices should return something like:
List of devices attached
2010830023232004 Â Â device
If you’re trying to change the header image, and the old image seems to be stuck, make sure you turn off WordPress Super Cache before you change the image. Before you restart the plugin, make sure you delete cached files, or the old header will come back and haunt you.
Update: it works! And, suspiciously, I made no changes to the router settings, so I must add — with perhaps a smallish serving of humble pie, since I can’t prove I got the password right or wrong before — the following two steps to the troubleshooting script:
I have a Barnes & NobleNook Color. Well, no; I have something the size, shape, colour, weight, and smell of a Nook Color, but it might as well be a brick. It seems that, unless you’re exceptionally lucky with your router choice, it won’t connect to wireless. This is, for what is essentially a wireless information browser, a bit of a problem.
What happens with my Linksys WRT350N is that the Nook shows network Authenticating, then network Remembered, then network Authenticating again, then network Disconnecting, then finally Disabled, secured with WPA/WPA2 PSK. I called tech support (1-800-THE-BOOK; and if you’re in Canada, use Google Voice from gmail, as you get into tech support, where using a real phone puts you on hold then gets you kicked off), where I was told to hard reset the machine. That didn’t work; now I have a machine stuck in perpetual “Register your Nook” mode until I get to a different network. The tech support dude suggested taking it back to the store, then got completely flummoxed when I said I was in Canada.
What I’ve tried:
Forgetting then reconnecting to the network; nope
Restarting the router; nope
Updating the router firmware; nope, already on latest version
Checking the Nook firmware; nope, already on 1.2.0
Entering the Nook’s MAC address into the router filter table; nope.
What I haven’t yet tried is downgrading my network to Wireless G, which seems to be the suggested solution. But, c’mon — this is a device released late last year. B&N want me to downgrade my stable, slightly elderly router just to get this new trinket to work? Not gonna happen.
Oh and while we’re ranting, Barnes & Noble: do you really need to send me a sales e-mail every bloody day? I’ve just bought one of your blasted things, and every morning I’m getting “Buy a Nook!” in my inbox. Make it stop, okay?
Well … sorta. I can’t upload any size of image, but previously I was limited to about 0.3MP (640×480). Now I can upload up to about 1.5MP without the dreaded Memory error. I can also use WordPress’s Auto Upgrade feature again.
Daddy Hogwash’s “WordPress 3.0 Upgrade Complete after Solving Fatal Error: Out of Memory Issue” is what fixed it. His suggested number of 40M fixed the auto upgrade problem, while I upped it to 64M to get larger images to work with my host, 1and1.com.
Update: There is no fix for this. Memory limit on my kind of hosting is ~34M. Any higher is not allowed. This seemed to work for a while, now doesn’t.
The original has her contact details, which I’ve left out here. I’d never used Inkscape before; the tricky part was working out the layer alignment while allowing for the bleed. I exported it as a 600 dpi PNG, then sent it to Staples Copy & Print. Turned out pretty well, I thought.
Catherine probably thought I was acting no more strangely than usual last night, when I was holding the Power Cost display unit in one hand, frobbing the electric stove control with the other, all the while watching a digital clock and cackling gently to myself.
All this makes me think I’m a bit further on with getting something from the Power Cost Monitor. Previous attempts using cheap wireless units (and cluelessness on my part — never forget that) got nothing, so I caved and bought the rather expensive but nice Parallax 433 MHz RF Transceiver from Solarbotics.
The Parallax unit adds an analogue output that’s proportional to the instantaneous signal strength. I hooked up the output to the trusty sdfatlib analogue logger, set the logger to sample every 50ms (figuring that, every now and again, it’s going to see part of a transmission) and this is what I saw:
Pretty noisy, I know. But look, there are regular peaks:
Here I’ve highlighted all the peaks with signal strength ≥ 200 (in arbitrary units, where 1024 would be full scale). It’s pretty regular; the largest peaks come in a shade under every 32 seconds, or a multiple thereof. If you need additional decimal places to validate your worldview, I’m thinking the period’s around 31.86s.
Observations made during last night’s frobbing and cackling episode seem to confirm that the display updates about every 32s. If you adjust the load mid-cycle, nothing changes until the update. If the display misses an update, it’ll refresh in 64 or 96 seconds.
I don’t yet know what bitrate the data comes through at, or the protocol. I’ve logged some data recorded at various rates: 433mhz_powercost_data. The file names give a hint at the data rate; L1200V04 was recorded at 1200bps, for example. I’m guessing that there’s some kind of sync header, then the total value and the current temperature (which was around/below freezing at the time). I need to work on that.
Update: I rewrote the logger to use the Arduino’s internal UART, since — lovely though NewSoftSerial may be — it causes millis() to report wildly inaccurate times at low bit rates. I recorded a bunch more data (powercost-arduino2.zip) in a slightly more useful text format. It has three columns:
the time, in milliseconds, at which the record was recorded
the time difference between this and the previous record, in milliseconds. Maybe not as useful as it could be. If adjacent records are about 31860ms apart, they’re transmissions from the meter.
120 bytes of data recorded at the current bit rate (given in the file name) encoded in hex.
I’ve also included the Arduino sketch, which could be better documented.
I’m pretty new to Arduino, and electronics in general. Sure, I used to wire up sensors to a bunch of dataloggers, but there wasn’t much variation or application of theory. I made up a bunch of Ardweenies, mostly to practice soldering skills, but now I’ve made them, I might as well use them.
ardweeny, breadboard, USB programmer and PSU
The Ardweeny is a tiny broadboard-only Arduino-compatible microcontroller board. It needs both a power supply and a means of programming it. Solarbotics’ own Breadboard Voltage Regulator Kit provides the juice, while a SparkFun’s FTDI Basic Breakout handles the USB serial programming. The FTDI breakout board can supply power, so I turn the power off to the board at the regulator when programming it. You can’t use shields with the Ardweeny, but it’s small enough that you can have a simple project on a small breadboard. It communicates with the Arduino IDE as if it were a Duemilanove.
The Ardweeny has pins clearly (if tinily) marked by function. To power it, you need to feed GND and +. The familiar A0-A5 and D0-D13 are present, if not quite where you’d expect them. There isn’t room to mark the digital pins capable of PWM.
For no particular reason (perhaps that spring finally looks like it might be warming things up around here) I wanted to make a a temperature sensor that would sample the temperature at start up, then warn if the temperature got more than 2°C hotter or colder.
I used an LM35 as the sensor. These are a bit noisy, so I added some smoothing (nicked, with little grace, from the Arduino – Smoothing tutorial). The temperature is indicated by three LEDs: red for ≥2°C over, amber for within ±2°C of the starting temperature, and green for ≥2°C under. I also wanted all the LEDs lit while the system was working out starting temperature. Here’s how it runs:
starting up, showing all LEDsshowing normal temperaturewarmed by a finger, showing ≥2°C over normalchilled by a frozen cayenne (!), showing ≥2°C below normal
I put the LM35 on A0, and the red, amber and green LEDs on D5, D6 & D8. The only reason I didn’t use D7 was that I didn’t have the right length jumper wire. 680Ω resistors are used to limit current through the LEDs.
Here’s the code:
/* lm35_plusminus - read temperature at startup then light leds if over or under  lm35 - analogue 0  red led - digital 5 amber led - digital 6 green led - digital 8  scruss - 2011-02-17 */
#define REDPIN 5
#define AMBERPIN 6
#define GREENPIN 8
#define TEMPPIN 0 // analogue
#define DELTA 2.0 // amount +/- from start to warn
#define READINGS 15
//declare variablesfloat tempC, start_temp, array[READINGS], total;
int val, i;
voidsetup()
{
  pinMode(REDPIN, OUTPUT);
  pinMode(AMBERPIN, OUTPUT);
  pinMode(GREENPIN, OUTPUT);
  // signal start of test by lighting all LEDs
  digitalWrite(REDPIN, HIGH);
  digitalWrite(AMBERPIN, HIGH);
  digitalWrite(GREENPIN, HIGH);
  // read initial values
  for (i=0; i< READINGS; i++) {
    delay(500/READINGS); // just so initialization is visible
    val = analogRead(TEMPPIN);
    array[i] =  (5.0 * (float) val * 100.0)/1024.0;
    total += array[i];
  }
  start_temp = total / READINGS;
  // test off, lights off
  digitalWrite(REDPIN, LOW);
  digitalWrite(AMBERPIN, LOW);
  digitalWrite(GREENPIN, LOW);
  i=0; // just to initialize
}
voidloop()
{
  // some cheapo smoothing copied from the Smoothing example
  // in the playground
  total -= array[i];
  val = analogRead(TEMPPIN);
  tempC = (5.0 * (float) val * 100.0)/1024.0;
  array[i] = tempC;
  total += tempC;
  i++;
  if (i>=READINGS) {
    i=0;
  }
  tempC = total/READINGS;
  if (tempC - start_temp >= DELTA) {
    // we're hot !
    digitalWrite(REDPIN, HIGH);
    digitalWrite(AMBERPIN, LOW);
    digitalWrite(GREENPIN, LOW);
  }
  elseif (tempC - start_temp <= -DELTA) {
    // we're cold !
    digitalWrite(REDPIN, LOW);
    digitalWrite(AMBERPIN, LOW);
    digitalWrite(GREENPIN, HIGH);
  }
  else {
    // we're just right !
    digitalWrite(REDPIN, LOW);
    digitalWrite(AMBERPIN, HIGH);
    digitalWrite(GREENPIN, LOW);
  }
}
Despite the smoothing, the LEDs flicker briefly as they turn on. I kind of like the effect, so I made no attempt to change it.
What I like about Arduino is that — within the limits of my sensor knowledge — the programming language does what I expect. The above program worked first time; worked, that is, save for me putting one LED in the wrong way round, so it didn’t light. I know I could probably replicate the same function with a few linear devices and other components, but it would take much more time and effort. It may not be the most elegant, but it does work, and gives me the satisfaction of the desired result quickly.
After bumping along at about 600Kbps for the last few weeks, Bell (through TekSavvy) finally kicked my connection over to 3 megabit. I don’t think we’ve ever managed this speed before, as I think I’ve been routed to a different exchange. Whee!
Update: Yowza! Looks like I’ve been upped to as close to the 5M that I can get …
After fixing the code in the awesome sdfatlib library, I’ve now got it logging the temperature of a cooling container of hot water:
You might just be able to make out the LM35 pressed up against the measuring cup.
I remember making a right mess of this experiment in my school final Physics practical exam. I also used to do this in my first job when bored testing Campbell CR10 dataloggers, making a nice 1-d cooling curve with a thermocouple and a cup of hot water.
I think the heating came on a couple of times, as there shouldn’t be bumps in the curve. Here’s the data.
I realize that I first started using X11‘s xedit in 1989. I’ve moved on a bit from editing ANSYS source scripts, but that means I’ve used it in the 80s, 90s, 00s and 10s.
Just to show you how things have changed, here’s a list of the most recent artists I’d downloaded pre-plan changes. The ones in red are ones you can’t get any more:
Barry Louis Polisar
Belle and Sebastian
Boards Of Canada — only one album available
Dum Dum Girls
Eels
Elizabeth Cotten
Elsinore
Euros Childs
Forest City Lovers
Frontier Ruckus
Gonja Sufi
Gorky’s Zygotic Mynci
Hold Your Horses!
Macy Gray
Michael Hurley
Mount Eerie
Pocahaunted
Someone Still Loves You Boris Yeltsin
Sun Kil Moon
The Delgados
The Moldy Peaches
The Tallest Man On Earth
The Turtles
The Whitlams
Will Powers
And here was me on a major Delgados kick, and they’re gone.
So cancelled my plan on the weekend, and got this:
Yep, if you’re on an annual plan, you’ve got to sit it out. They don’t offer refunds. So now I have to remember to go in every thirty days for the next nine months to find something – anything! – to download. It’s extremely shabby that emusic are holding over $100 of my balance to ransom. I guess they’re just trying to fit in with the mainstream music industry …
OooOOooh! teh pritty! I’ve temporarily rooted my Nook Color to run the latest version of Android from microSD using the following instructions: [ROM][CM7] [v1.3] Size-agnostic SD Card image and CM7 installer for SD Cards. – xda-developers. It’s a bit slow.
You might just be able to make out the 
I think the heating came on a couple of times, as there shouldn’t be bumps in the curve. Here’s the 
I realize that I first started using 
