It's made The Register too:
https://www.theregister.co.uk/2017/04/05/oscilloscope_pong/
It's also a non-trivial amount of soldering. But, hey, you don't have to build it all in a single weekend.
It's made The Register too:
https://www.theregister.co.uk/2017/04/05/oscilloscope_pong/
Wow!
With all this interest, it makes me wonder how many kits one could sell for this ?
(Being practical it would be very limited, as how many people have access to a suitable scope, too few I imagine).
Okay, so here's what I came up with:
http://timb.us/PDF/Scope_Pong_XYZ_V3.pdf
I shifted the diodes around a bit to save space, but I still kept it very compact and the lines running to the drain nodes of the JFETs are each around 20mm. I still need to place the trimmers (ignore them in the image), but so far so good I think.
It's made The Register too:
https://www.theregister.co.uk/2017/04/05/oscilloscope_pong/
Wow!
With all this interest, it makes me wonder how many kits one could sell for this ?
(Being practical it would be very limited, as how many people have access to a suitable scope, too few I imagine).I'd use this project as a measure of how good a digital scope in X/Y mode can emulate a real analog scope.
Basically it will be one of my test bench marks when purchasing my next digital scope.
It's made The Register too:
https://www.theregister.co.uk/2017/04/05/oscilloscope_pong/
Wow!
With all this interest, it makes me wonder how many kits one could sell for this ?
(Being practical it would be very limited, as how many people have access to a suitable scope, too few I imagine).I'd use this project as a measure of how good a digital scope in X/Y mode can emulate a real analog scope.
Basically it will be one of my test bench marks when purchasing my next digital scope.
Okay, so here's what I came up with:
http://timb.us/PDF/Scope_Pong_XYZ_V3.pdf
I shifted the diodes around a bit to save space, but I still kept it very compact and the lines running to the drain nodes of the JFETs are each around 20mm. I still need to place the trimmers (ignore them in the image), but so far so good I think.Perfect.
Digital scopes do vary somewhat in their X/Y behaviour. Not all have Z inputs. The RTB2004 has, AFAIK uniquely, an XYY mode, which will show two XY traces in different colours. It may be that there are a few true dual-gun CRT scopes that can do this ( obviously not in different colours) .
If the output bandwidth is within the audio range, it would be useful to record the output to a WAV file so people can test on different scopes.
Organizing the kits, shipping, customer communication etc. is always a lot of work in my experience with my C64 Kerberos cartridge. The easiest way might be to contact a manufacturer like Evil Mad Scientist, who sell the 555 kit:
http://shop.evilmadscientist.com/productsmenu/652
and ask them, if they want to sell a pong kit. Then you can sell them the PCB layout for a good one time price. Maybe less profit than when you do it yourself, but no risk and no tedious manufacturing and shipping work, but still everyone can buy the kit.
If you want to sell it yourself, iteadstudio has an assembly service, for fully populated boards, which some people might prefer:
http://support.iteadstudio.com/support/solutions/folders/1000212715
They say up to 25 boards, but maybe they can help you find a cheap service for larger quantities as well. Their boards are very good and cheap, so I guess their assembly service has the same quality. Maybe get a quote from them for 25 of your boards, then create a Kickstarter project with minimum funding required to pay the 25 boards (with a good factor like 3x for all the work etc.), no risk. Judging by the media echo, it should be no problem to sell 25 boards. And of course, some people, like me, would like to buy a kit, so this should be another Kickstarter reward.
Tonight I got the power supply section done:
Tonight I got the power supply section done:Would be worth making sure there's space to mount the caps horizontally , and have holes for securing wires/cableties as these will be the tallest parts.( Maybe also the voltage regs?)
I'd also suggest you include a polyfuse on the input for safety.
Maybe also a PCB-mounted on/off switch.
Originally I was actually going to put in a polyfuse, but couldn't decide on if it was really needed or not. I don't suppose there would be any issue placing it on the AC side of the rectifier? (It just occurs to me I've never seen them rated in anything but VDC, but I can't think of any reason why it wouldn't work, so long as the rating is above the peak AC voltage.)
I figured the user would route either the 120/240VAC through a panel mount switch before going into the transformer, though I could add a DPST switch between the terminal block and rectifier for good measure. (The user can always jumper it if they don't need it I guess.)
Hmmm, those little TO-220 heatsinks probably have a thermal resistance in the vicinity of 25-30 deg.C/W. The positive rail one will be sweltering at around 80 deg.C at a minimum at room temp. given the current consumption of the positive rail, not counting the possible additional drain of an add-on scoring unit. 800mA will melt some silicon.
15VAC rather than 18VAC input will give you enough regulator headroom with adequate filtering after rectification, and about half the power dissipation.
The trimmer potentiometers for adjusting the regulator output voltages should be shifted to the feedback resistor leg between the control transistors base and ground. That way if the trimmers wiper goes open circuit the rail voltage will collapse to around 7V, rather than go in the opposite direction and saturate close to the unregulated input potential.
I think it is important, as someone may use a big-ass transformer they just happen to have available, which could make a lot of smoke.
BTW you appear to have forgotten a centre-tap connection for the transformer. Obviously you need 2 PFs.
May also be worth adding a footprint (connector or links) for DC-in, in case someone already has a suitable supply.
Okay, Polyfuse it is.
Okay, Polyfuse it is.
I would like to have good old glass fuses. With fuse holders, in case someone blows it up. AC side would be best, then it would trip too if the rectifier shorts.