[edit 5/8] Added some movies below - probably should've put them here, I didn'realize I could edit the post days later... So I got an old 1950's tube 'PocketScope' for just shipping cost from someone cleaning house. It's the perfect size for a vector display project... I've played around with vector displays before, but my trusty HP180A scope is simply too big and I need it for benchwork, so I never really pursued the idea. But basically it's a simple 2 chip project, an Atmel AVR with a 7625 4 channel DAC. Plans are to turn it into a Scope Clock with optional usb for 'live' vector display from pc/laptop. I just love tubes! It's amazing that a 50+ year old piece of test equipment still powers up and works. A couple of the old paper caps have dried up and need replacement, but overall it's in very good shape. I very much doubt the hardware I purchase today will be operational in 50+ years. [edit] It would also be cool to build something similar with a tiny 1" tube (3LO1I cheap on eBay) and use it in a pc mod [edit 2] I'm officially a minimodder Yay! Now, where'd I put that dremel...
i have always wanted to do that with a scope but dont have the skill or time. is that yours if not can you give me a link to it i want to see more. and yeh a mini one inside a computer would be realy cool. but do you think it would need some kind of shealding around the HV circuits ?
That's mine! Just built it last night. It's actually not that complicated (depends of the point of view, of course)... Having a working scope with XY capability certainly makes things much easier. I may still go the 'from the ground up' way as in the link I posted above, but getting the right combination of voltages and components is likely to be a bit of trial & error. Basically the AVR microcontroller sends 9bit parallel data to the 7625 DAC for each axis. This gives me 512 x 512 resolution on the crt. The DAC is capable of 12bit data, but that is far more than I need so I just use the upper 9 bits. A control signal causes the DAC to update it's output voltages, causing the point on the crt to move. More complex displays send start and endpoints and the line is draw on-the-fly, but the timing and linearity of that is more complicated than what I'm doing. Still others use analog signals to create lissajous patterns. I just move 1 'pixel' at a time. Actually, coming up with an efficient line drawing algorithm was the hardest part! A 3rd input into the scope blanks the display when I have to move from one object to another. Then the whole pattern keeps going round and round, and what we see is the result of persistance of vision. If you are interested in something like this, I suggest you check out that earlier link.... it's a great reference and has other good links as well. Having a working scope with XY capability will also be a great advantage. Lastly, yes you'd need to shielding for two reasons... 1 the obvious high voltages required (typically 400v - 800v), but also the crt tube is sensitive to magnetic and emi; it will distort the display. I'll have some more pics and a progress update on Monday.
Nice, really effective and cool. I love tubes, especially as old equipment like that is always built really well - nice brass axles on the pots etc. A vortex swirly effect would look really cool as well. I might give this a go, as I have an old scope but had never thought of driving it like this.
Yeah, when I was emailing the guy I didn't know what shape it was in and was fully intent on gutting it just for the parts. But after seeing it I just fell in love and couldn't bear the thought of killing something that had survived for so long. It totally has that "they don't build'em like that anymore" appeal. Plus, I got the original wooden case that has nice vintage tolex and blue felt. I also tracked down the original manual, god I wish they still wrote these things like this; it has complete theory of operation and service data. It's a cool retro read in itself, when frequency was still kilocycles and capacitance was in mmf (micromicrofarads = pf today). Plus it outlines quite a few more complicated testing procedures than I would have thought they were doing back then with such 'simple' equipment. Pocketscope SA11 (5mb pdf) [edit] The other neat thing is how the 'Television' term is so prominent... Remember, when this things was built TV had only been on the air for a couple of years...
yeah, they changed that when they got rid of the department of redundancy department. *Rimshot* wicked sick retrotech though. I am also a lover of tubes, but I've mostly stuck with NOS nixies and triodes.
ROTFL [ ROTFL ] ...sounds like something from Brazil Me too... built this a while back (before I was into uc's, all DTL / TTL):
i love nixies as well. i was thinking i might use some of these to make a mini display for my case http://cgi.ebay.com.au/Set-of-six-I...ryZ78827QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
or several in the front of the case as vector-analog gauges and digital temp readouts. i wanna build a usb vector display but wouldnt even know where the heck to begin..... O_O
Did a little coding this weekend testing different display ideas. The couple of folks I showed the scope to said the look and 'scope' name reminded them of an old sub radar scope... so one of the ideas was to replicate that look. Here's 2 preliminary versions; the display is actually much smoother in real life, my digicam uses some funky 25fps video rate and had a little trouble with the low light needed to highlight the display, but you'll get the idea... radar1.wmv radar2.wmv I was trying to get the clock hands to 'blip' a little more, but was having trouble with the intensity circuit. Finally tracked it dow to this: Bad 50 year old capacitor, or an old sweaty stick of dynamite? Unfortunatley, Radio Shack doesn't have the selection of 400V+ caps that they used to have. That would be cool! I'm pretty new to usb myself, but I have successfully made a couple of interfaces based on Igor Cesko's AVR design. However, in order to make use of anything usb, you also require the ability to code in some pc language - in my case I used vb or vb.net.
i bet if you went into radio shack and asked for a 400v cap they would probly say something like but the voltage at the wall is only 110v. why not have some cool vertical scan bar type thing going on. its hard to explane what i mean edit: juts found this about half way down the page is some nixies in a pc http://www.electricstuff.co.uk/nixiegallery.html
Vertical scan, like tv? Yeah, I have Mike's bookmarked from a while back - great site. Nixies would look good in a pc. Back to their roots, in a way.
you can find high-voltage mylar caps like that attached to motors and such. I pulled three out of a ceiling fan. they were only 7uF, 10uF, and 5uF, but they were good enough for a voltage doubler.
