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La Lune

If you are a night shift worker finishing, or an early shift starting; take a look at the moon at around quarter to five (CEST) / quarter to four (BST) this coming morning. You'll be treated to the rare spectacle of a "super moon" and a lunar eclipse. The moon should be big and crimson red.
I won't be watching it. I'm no longer the go-to guy for night shift. Yay. Okay, this supermoon and eclipse might not happen again for another 38 years (I'll be eighty and surely gaga by then), but night time is a time for sleeping...
Actually, it has been proven that shift work is potentially harmful and night shift is definitely harmful. Worse, even, than goto.


Square waves

Spurred on by a comment from David Pilling, I opened up my function generator to see how the signals were coming directly from the ICL8038 signal generator IC, instead of at the far end of op-amps and the like. The first thing I notice is an apparent discrepancy in the datasheet. The blurb describes the device as being able to generate - quote - Wide Frequency Range . . . . . . . . . . . .0.001Hz to 300kHz; however the technical details say - quote - Max. Frequency of Oscillation fMAX 100 - - 100 - - 100 - - kHz (three values for three different versions).
I'm guessing from this, that 100kHz is a more viable maximum than 300kHz.

As it happens, this is the square wave being read from the TTL output. I don't know the exact speed, for if I go faster than this, the signal just fizzes out completely. If you want to try to work it out yourself, each graticle square represents 2µS. Judging by the position of the knob, I'd guess it to be around 70kHz or so.

You can see the duty cycle is way off of being even.

Why? I don't understand what is going on here, as the ICL8038 makes a rather appalling square wave, but it does look more like a square wave. Here is the square wave measured directly from the IC itself, running at max speed. Graticle = 2µS so this, spanning five squares, ought to be around 100kHz. The fall time is okay, the rise time is really horrible!

I think that there are several combining factors here. Possibly the age of the equipment, old capacitors, and parts that together may be inadequately specced for the task? Certainly the difference between square wave out of the IC and square wave on the TTL output couldn't be greater. Also, interestingly, thr triangle wave and sine wave directly from the IC are good and reliable and even right up to the 100kHz mark. There is a bit of jitter at the crests of the sine wave, but it is fairly minor. Here is the sine wave at ~100kHz coming directly from the IC:

Here, as a "throw it in" example, is me measuring the square wave. You can see the probe has a little plastic cap fitted to allow pins of ICs to be safely probed without risking missing and inadvertently shorting two pins:

The final picture that I shall leave you with is a suggestion of the "truth" of this piece of school equipment. Signals up to 100kHz shifted around the place on pieces of unshielded ribbon cable? Heck, the square wave output runs on that track you can see on the right of the board (as you look at it) all the way to the rear, to the ribbon cable which passes all the way back to the front, which selects the signal passed on a different part of the ribbon cable all the way to the rear, to go back into the board to be amplified as desired and then fed out of the output socket(s), this time using a solid wire...which, you guessed it, comes from the back!
It's a good thing that this stuff is encased in a solid metal box - I could imagine it taking out an appreciable chunk of LW in nearby receivers otherwise!



A single solitary euro bought me this at a vide grenier:

Taking three AA cells, it is a comically novel way of cleaning dust and stuff off my table!

If you look below the pipe... yup, it even comes complete with a crevice tool.

And to top it off, the pipes and other pieces can be stored inside the Henry itself.


Braun NovoScan A6

I found a Braun NovoScan A6 for €12 in a shop selling end-of-line things. This is an A6 (more or less "postcard sized") automatic scanner for postcards, photos, and the like.

Using it couldn't be simpler. Insert an SD (XD/MMC) card (FAT16 or FAT32). Press the power button. Wait 36 seconds for it to start up. Then just feed a photo or postcard face up into the device. It will begin scanning immediately, passing the photo between motorised rollers, it will crop the scan to the size of the inserted content, and it will write it to the SD card as a JPEG file. The scanning resolution (via an A6 width Contact Image Sensor) is 300×300 dpi at 24 bit; and the scanning time for a typical sized post card is about six seconds.
You don't even need to remove the SD card. There is a USB port for connection to allow the scanner to be used with a computer, though I've not tried this. I think it can interpolate up to 1800 dpi. Or, in other words, lie shamelessly.
On the plus side, it can also function as a somewhat lethargic removable media device, so you can scan stuff and then read it directly from the SD card inserted in the scanner.

Here's a crappy video:

The scanner seems to have difficulties with solid areas colour in halftone patterning, as you can see in this example, which is a clipped out part of the full scan:

That said, here is the photo scaled down to fit on a web page. Not bad. Not for a scanner that cost €12!

Maiko (dancing girls, not the same as Geisha) in front of Daikakuji Temple, Kyoto.

Here is a scan of a photo of my Pi. Note the patterning towards the bottom of the image:

This scan looks a bit naff and dotty. It is actually a fairly faithful reproduction of the original postcard:

Aoi Matsuri (Hollyhock festival), Kyoto, May 15th.

This must be an old card as the description says that Sendai City is "decked out in gay array". I don't think that word has been used that way since the sixties

Festival of the Stars, August 7th, Sendai (yes, that Sendai).

Every good Japanese girl should know how to play the Koto. I suspect this is probably a class-related anachronism, akin to good Western girls performing piano recitals...

The postcard calls this a "most proper accomplishment" for young ladies of Japan.

Modern stuff (printed with better technology) scans quite well, though the scanner didn't quite manage to capture the intensity of the colours used.

Hey, Nico!

Another use for the scanner is to make digital copies of till receipts. I bought a hedge trimmer, and the E.Leclerc provided me with a crappy thermal receipt. My local Super U prints guarantee receipts with a small dot matrix. Why? Simple - I have a two year guarantee in accordance with my rights as a consumer. I would be surprised if that receipt can be read in six months, never mind two years. Well, hey, I now have a copy of it...

And, the final example, Tokyo Station. This postcard is culturally important as not only does it depict a vastly less developed Tokyo (the same view is impossible now), the station being originally built in 1914; but it also shows the station with three levels and impressive domes. Much of the station was destroyed in the firebombing of 1945, and while it was rapidly rebuilt, the rebuilding was a two-level building with simple angled roofwork instead of domes.
However, a massive five year reconstruction project was completed in 2012 which finally brought the station back to its pre-war appearance, complete with domes.

I don't know when this card was made, however the writing on the back is dated 11 / 1 / 1923.

As a special bonus, here's the reverse of the Tokyo Station card:

As you can see, the scanner isn't as good as an expensive flatbed with computer control, however it isn't bad for an inexpensive standalone unit. It is a shame there is no method to control things such as sharpness, compression level, and so on. However, I suspect adding that sort of functionality would somewhat increase the product price. It is aimed at performing a specific task to a low price point, and it does that task fairly well considering.

I would imagine it is running some sort of ARM processor, and the 36 second start-up time might hint at an embedded Linux, perhaps? I can't tell you. Being made for the German market, all I can see is a big RFI shield firmly soldered in place. The board inside is tiny, but that means nothing these days - look at WiFi repeaters, the Pi, etc.

Supplied with the scanner is a CD-ROM with some sort of software. Not tried it. There is a calibration card which contains a code to trigger the scanner to self-calibrate. There is a little lens cleaning swab. And finally there is a pocket for "curled photos" that will hold them flat as they pass through the scanner. The pocket is useful for all photographs as it helps ensure that the photograph passes through correctly aligned, which isn't always the case if you are shoving them in the front of the unit. The pocket has a code which slows the scanning slightly as well.
Take a look at the video to see these in action.



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Zerosquare, 28th September 2015, 00:07
The video doesn't work on your blog - it says embedding has been disabled.
Rick, 28th September 2015, 00:49
Thanks for pointing that out. Fixed now.
David Pilling, 1st October 2015, 02:58
About the difference between the TTL and chip outputs. If you imagine the TTL chip output switching high when the input passes a threshold value, then maybe the two can be reconciled. Obviously a lot of rounding going on, and one wonders why the chip output is not square to set of with. Things were slower then - none of this GHz stuff.

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