This is an ATtiny85. It’s a multi-MIP microcontroller. It’s $2.50 in quantity one. It has 8K of flash. You can program it in C. It’s the same size as a 555. It will kick your ass.
8 legs of awesomeness
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Monthly Archives: October 2011
last of the daisy-ish things
Cleared out a ton of these from the front garden. They smell good when you pick ‘em.
(Taken with Catherine‘s nifty new camera.)
Legions of young Canadian photographers say …
“Hey Henry’s, that’s not how you spell ‘environment’!”
24 pins to the platen
Thanks to Seneca, I now have this noisy, slow behemoth in my basement.
It’s kind of neat that Ubuntu supports this 24 year old printer out of the box.
24 hours after sending 286 digital QSL cards …
Of the 286 secure digital QSL cards I sent, 8 were undeliverable. I’ve had 25 responses so far:
- Fourteen positive
- Three wondering if I hadn’t seen their confirmation on eQSL/QRZ/LoTW
- Two that don’t accept QSLs of any kind
- One language issue; I have “Report” when “RST/RSQ” might be clearer internationally
- One completely neutral
- One auto responder
- One with no record of a QSO in their log
- One saying their callsign has been hijacked and that they are no longer an active ham
- One negative
Of the positive ones:
- Two have also sent real QSL cards (thanks, guys, but really, you shouldn’t have …)
- Two asked how I did it.
Pretty good and quick response, I thought.
(Not Just) Firefox’s “Pile of Poo” Easter Egg: 💩
For a reason best known to the Unicode consortium, there is now the symbol U+1F4A9 “Pile of Poo”: 💩. If you happen to create a web page with this delightful character in the title, Firefox does something special:
Yep, that’s a smiley face poo, a bit like Mr Hankey. Oh dear.
Actually, it seems it might be an OS X Emoji thing, because Safari renders it in the title like that, and in the text as (enlarged to show texture):
iOS has it covered too:
Blackberry’s browser just shows a small black square. Android, rather sensibly, shows an empty square. It must be an Apple thing.
“Thanks” go to tchrist‘s comment in unicode – Why does modern Perl avoid UTF-8 by default? for alerting me to this character, and letting us know about the Symbola font that supports it. Yeah, cheers Tom …
Secure digital QSL cards, part 2: shell script
Following on from Creating secure digital QSL cards with your LoTW certificate, here’s a Bash script to generate encrypted signed PDF QSLs. You will need to edit the certificate file name, the QSL blank file name, your call sign, your LoTW password and the PDF encryption password. After doing so, please keep the script safe, as whoever has your LoTW password can pretend to be you.
The only checks that this script doesn’t do (and probably should) are if you have pdftk and PortableSigner executables in your path. PortableSigner is rather weird the way it runs; you need to specify full paths for all files, or it dies.
The script is called like this:
mkdqsl.sh callsign date utc mhz mode report
for example:
mkdqsl.sh VE3KPK 2011-10-02 2341 7.03581 CW 499
Code below the fold.
Good old PCD0992 …
I found the good old Kodak Photo CD sample images on the site linked through from the photo. Test images for MFSK image radio transmission, here we come!
I got this CD with OS/2 Warp back in early 1995. My machine didn’t like Warp at all; it repeatedly fork-bombed in the file manager, so it was essentially a £40 paperweight. So burned was I with commercial software that I bought a Slackware distro so I could run something more fun that Windows 3.11. I’ve been happily running Linux since then.
No work of art …
but it is my first working lead-free, SMT soldered circuit. I have two SoftRock Ensemble RXTX radios to build, and I thought it would be better to melt a $10 trainer kit than a $100 radio. It works as expected, though I wouldn’t describe the red/green LED’s insane flickering to be “an attractive and functional SMD dual color LED flasher”.
Flux is your friend here. I tried Chaney’s recommended method of supergluing components on the board, but that didn’t work. What ended up best was applying flux to all the pads, supplying the thinnest layer of solder possible, refluxing the pads, then flowing on the components. A steady hand, a magnifier, tiny (½mm) solder, good tweezers and a pointy soldering iron helps. Some kind of fume extraction is good, too, as Pb-free flux is a tad acrid.
I don’t miss eutectic leaded solder. Sure, it’s easy to use, and it’s got a kind of magical quality that it’s below the melting point of either lead or tin. But Sn-Ag solder is toxic enough, and I don’t need to dump more lead in the world.
Creating secure digital QSL cards with your LoTW certificate
Hams have sent out QSL cards since the hobby began. It may be less popular than it used to be, because mail seems slow now (especially when QSL bureaux are used), and there are online alternatives like eQSL, QRZ.com, and the ARRL‘s Logbook of the World (LoTW).
LoTW has been criticized for being too complex. It uses an X.509 public key signature to verify your submitted log entries, and a QSL is confirmed when the other party sends in a matching entry. In a way, it’s rather elegant, as the LoTW server does the work of matching the entries, so QSLs “magically” appear in your log. You don’t get a fancy QSL card in the mail or on your screen, and I think a lot of users miss that.
X.509 might be a bit unweildy, but props to ARRL for setting up a industry standard, robust (-ish; X.509 has its flaws), general purpose signing infrastructure. Since other file formats — notably PDF — support X.509 signing, you can use your LoTW certificate to make other data tamper-evident.
Here I document a method of creating a digital QSL card that can be e-mailed, and subsequently verified by the recipient as being legitimate. Any alterations to the file will break the signature, and the file will just appear as a regular PDF (or not display properly). The process can be used to sign any other Acrobat file. There are probably more streamlined ways to do this, but I only came up with it last night as the beginning of a scriptable solution.
You will need:
- Your ARRL LoTW electronic certificate file. This is called callsign.p12; mine is VA3PID.P12
- A means of making a QSL card as a PDF fill-in form. I used Scribus; it’s a free but powerful DTP system.
- Pdftk, “the” PDF toolkit, to apply the QSL details to the PDF form. If you’re on Windows, you might want the Pdftk GUI.
- PortableSigner, a java application for signing Acrobat files using an X.509 certificate.
(Quite a bit of what follows was learnt from the two pages Your first PDF form with Scribus – Scribus Wiki and filling in forms with pdftk, so thanks to the authors of those for the guidance.)
First, make your QSL card. Since you’re not going to print this, it can be any size you want, but postcard size is standard. At the very least, create spaces for the recipient callsign, the date, the time, frequency, mode used, and signal report.
Under these headings, I’ve made six PDF text form fields. Scribus creates form fields like text frames/boxes. I used plain text fields (which are selected by this icon: 
), centred text, and with the name of the field set from the PDF Options → Field Properties context menu. Each field needs a different name. I used callsign, date, utc, mhz, mode, and report.
Save your QSL card as PDF. It might be an idea to check it to see if the form fields are really there and editable:
Now it starts to get really nerdy. Adobe specified the Forms Data Format (FDF) to allow PDF form data to be slung around. FDF looks a bit like PostScript or raw PDF:
%FDF-1.2 1 0 obj << /FDF << /Fields 2 0 R>> >> endobj 2 0 obj [<< /T (callsign) /V (VE3KPK) >> << /T (date) /V (2011-10-02) >> << /T (mhz) /V (7.03581) >> << /T (mode) /V (CW) >> << /T (report) /V (499) >> << /T (utc) /V (2341) >> ] endobj trailer << /Root 1 0 R >> %%EOF
If you think of the T & V values above as Tag and Value, you can see that the file defines callsign=VE3KPK, date=2011-10-02, mode=CW, and so on. This step can be easily scripted. If you’re not sure what the fields are called, pdftk has a “dump_data_fields” option that spits out the field names as plain text.
pdftk is also used to put the data from the FDF file into the PDF template. It’s a slightly hairy command line:
pdftk QSL-blank.pdf fill_form VE3KPK.fdf output QSL-VE3KPK.pdf flatten
Here the source file is QSL-blank.pdf, the FDF data is VE3KPK.fdf, and the output is to QSL-VE3KPK.pdf. The flatten option turns the pdf form into regular, uneditable PDF. (These details are from a real QSO, by the way, and by utter coincidence I’m writing this in a hotel in Ken VE3KPK’s home town in Northern Ontario.)
Checking that this worked in Adobe Reader:
For many people this is probably enough (or perhaps, too much already!) but I really want to have a digital QSL card that will stand up to some scrutiny. This is where your LoTW certificate file comes in.
PortableSigner is a java application for signing PDF files. It seems quite happy signing the files made in this workflow. It can run from the command line, or as a windowed application:
You use your .p12 signature file and its password to sign the PDF. Once the file is signed, you can send it to your contact, and they can prove (and hopefully, any certification/contest agency will agree) that the contact was confirmed.
Viewing the signed document is deeply unimpressive:
It’s not such a big deal that Reader says that “the validity of the certification is unknown”. It’s just that Adobe doesn’t have the ARRL’s certificate loaded into everyone’s reader (what!? mock outrage!) and so it doesn’t match a certificate it knows about. You have to dig a bit deeper into the signature panel to check out who is responsible for this.
Well, that’s a start; at least it was signed by someone with my e-mail address. There’s more under Show Signature Properties:
There’s the ARRL signature in there. Buried deep in another properties tree is my callsign; can’t find it today, but I saw it in there last night. Either way, the digital QSL PDF is now signed and certified that it came from me, as an ARRL LoTW user.
not your dad’s multimeter
I’d been surviving on a series of sub-$50 multimeters for years. They’d give an approximation of a reading,then fail miserably in a variety of stupid ways. The last one, a rip-off of an Extech, decided to show me how its wires were connected to the probes. “Barely” is a fair description.
So I thought I’d buy a decent meter. One that had heft and gravitas, like the Avo 8 that my dad used to bring home from work. The Avo — seemingly constructed from bakelite, glass and lead — didn’t just take readings, it told you The Truth on its mirrored scale.
So I bought an Agilent. Reliable company, all the right features, beeps politely only when required; a very, very sensible meter. Then I found these in the package:
Dude, what?! Skins on a meter? Meters aren’t toys. Meters are sensible things used by sensible people. We don’t want our work distracted by thoughts of Space!, America!, Sports!, or Some Kind of Bug Thing Eww Squish It Squish It! If you were able to get “skins” for the Avo 8, they would be about Wisden, sheds, and the TSR2.
Despite the sticky nonsense, it’s a good meter. I also managed to catch a Handheld Digital Multimeter Cash Back Offer, so it’s cheaper than competing Flukes and Extechs.