Stepstones to construct simple digital oscilloscope?

[jucole]

I've just ordered a 320x240 2.4" tft lcd module with touch for some scope ui experiments.

[EEVblog]

So this got me thinking about how I could make a ridiculously simple digital oscilloscope and I really want to see if it would work...
Take an LM3914, feed that to 10 10bit latches, then use a decade counter triggered by a 555 astable to scan the latches to one by one latch the output of the 3914. Absolutely worthless with not even 4 bit resolution, doesn't even have a trigger, but totally dead simple.
I think you could actually make it somewhat useful by using an opamp to work as a trigger by resetting the decade counter at a certain voltage, make the timebase specific and adjustable with a rotary switch to select a specific frequency for the 555, and a rotary switch to select a resistor divider for the 3914.
Any thoughts?

It's been done and published, or something close to that. IIRC with an 8x8 LED display matrix, and I have the magazine somewhere.
Someone I know also a schools project way back in the 80's with the same project.
Can dig these out of the archives if interested.

My old DSOA design is pretty simple and does not require any micro or FPGA:
http://www.alternatezone.com/electronics/dsoa.htm

Dave.

[andyturk]

Please, don't  flame me,  I'm  newbie and a dreamer, but I would like to know what knowledge/steps are required to build digital oscilloscope with LCD screen, like this project from germany : http://www.mikrocontroller.net/topic/228997? (I'm clueless about German language).

Thanks!

Hey, don't listen to all these wet blankets!

Get yourself a microcontroller with ADC, a display an just build something. You can probably create an oscilloscope "of sorts" in a week's time depending on what's lying around on your bench and how comfortable you are with the software end. And, as one noob to another, I think it's a fine project to dive into.

It may not replace a real scope for actual work, but you'll certainly learn a lot.

[Mechatrommer]

designing simple low BW diy dso simple GUI is fine, will teach us and take our time alot. i've been thinking about the same. but when we aiming at something commercial like 1GSps, calculating the cost, i think i'll just buy existing on the market. try outrunning the nano crap is possible, but not the existing entry level like rigol.

[jucole]

Many thanks for the DSOA post - it's a great learning resource!    I really like the MkI schematic because it's about on my level atm and it looks hand-drawn?   In the pc software, was timing an issue clocking the nibbles out, in that perhaps the pc tried to clock too fast for the chips?