Spark Logic

$10 O-Scope revisited

Over the last few days I’ve been playing with Ray’s STM32STM32Микроконтроллеры и процессоры…Map magic glue code, ethernet compiles, just WARNING: library LwIP claims to run on [ stm32 ] architecture(s) and may be incompatible with your current board which runs on [STM32]…[STM32GENERIC] F429i Discovery Oscilloscope idea.

Image

Some preliminary results are available here..

https://github.com/pingumacpenguin/STM3 … ontruction

My take on the Scope Sketch is here..

https://github.com/pingumacpenguin/STM32-O-Scope

Its a fun little project and well worth building just for the entertainment value. Currently bandwidth is a little limited, but with a little extra effort it would be possible to make a fully functional 2MHz Scope for next to nothing. Ideal for probing i2c, audio and other low speed signals.

EDIT: We managed to squeeze the maximum speed out of the ADC, read further through the thread for details. The github code includes all of the enhancements made of the course of this thread.

Replies20

Fri Jan 20, 2017 1:07 am

That’s just a much lazier way :D

Fri Jan 20, 2017 5:25 am

Vitorbnc wrote:That’s just a much lazier way :D

Fri Jan 20, 2017 8:56 am

Vitorbnc wrote:Thanks for all the help, after a bit of research it is working! The solution I found was using another pin for frequency counting and connect it to the scope input. I’ll attach the code I wrote in case anyone is interested ;)

Fri Jan 20, 2017 7:25 pm

Yes, I’ve thought about these problems too. Maybe I’ll try using a hardware timer to do the counting later and see if it improves precision.

Mon Jan 23, 2017 10:52 am

Preview of the work in progress: :)
Image

Mon Jan 23, 2017 10:58 am

rexnanet wrote:Preview of the work in progress: :)

Mon Jan 23, 2017 11:19 am

ThunderOwl wrote:rexnanet wrote:Preview of the work in progress: :)

Mon Jan 23, 2017 11:25 am

Great things coming … :) By best luck wishes here!

Thu Feb 02, 2017 7:52 am

Hello, everybody! Hello, Rexnanet, MausiMick, Andy – what’s new? ;-) I am about to make boxed “test-bed” for O-Scope variants, or, pretty much anything else that is based around “BluePill”+TFT SPI combo. So I am wondering, what are, guys, your current versions? I am considering count of encoder(s) and buttons to have in this test “rig”. Can you guys please share your current constructions? Thank You!
Oh, and for those who were following similar projects (to get inspirations and what not) – there is a new thing going on from user “GFX”, scope v3.0 (forum radiokot.ru). Tkae a look, if interested. Materials are in “GFX” user’s signature link.

Thu Feb 02, 2017 10:16 am

Hi ThunderOwl,

I’ve been working on the changes I’ve mentioned before.
They are quite a few and I haven’t been able to move as fast as desired but I’ve been moving forward.

Probably this weekend I’m going to be able to work on this and release a working version with most of the functions.
I’m using a single encoder and I think it will be enough but maybe 2 or 3 would be more “user friendly” :)

As for construction, it’s still not “enclosured” yet :) unfortunately…

“GFX”? I’ll check it out :)

here is the status :)

Working (reasonably :D ) :
– menu navigation
– menu values changing
– trigger edge (but the waveform doesn’t change accordingly! lol must take a look into this maybe with a sinus wave)
– trigger level (values from 0 to 4096.to be corrected to volts later)

– trigger level indication!!!! (that red trace on the left of the wave :D. have to change it to an arrow or something)

Implemented but still not tested:
– trigger mode (Auto, normal, Single)
– Run/Stop
– timebase scale (modified to show “50us”…”100us”…”1ms”, etc and reflect the real timebase :) )
– vols/div (modified to show “50mV”…”100mV”…”1V”etc only zoom factors. The MCP6S22MCP6S22Аналоговые, логические и силовые компоненты…e Smile ) – vols/div (modified to show “50mV”…”100mV”…”1V”etc only zoom factors. The MCP6s22 will come latter so will have to make some adjustments…) Still to do: – dual channel (…$10 O-Scope revisited will come latter so will have to make some adjustments…)

Still to do:
– dual channel (on the way) (missing: ADC capture, drawing, 2nd channel trigger)

Thu Feb 02, 2017 11:20 am

ThunderOwl wrote:Thanks for info, Rexnanet! About dual channel – would it not sacrifice sampling rate for each?

Mon Feb 06, 2017 12:12 pm

Soooooo,
As announced before… here is a preliminary version of my approach of the STM32STM32Микроконтроллеры и процессоры…Map magic glue code, ethernet compiles, just WARNING: library LwIP claims to run on [ stm32 ] architecture(s) and may be incompatible with your current board which runs on [STM32]…[STM32GENERIC] F429i Discovery -O-scope.

– volts/div is still WIP. (is more like a zoom function…)
– dual channel is still WIP too.

I was faced with an unexpected issue with the vertical graticules as I thought I had 200pixels but it’s really 220 and the math is off a bit, using the present method.
So I’ll probably lower it to 200pixels and create a info area below (or above) the graph area.

(41.22 KiB) Downloaded 87 times

Mon Feb 06, 2017 12:37 pm

And, soooooo… much Thank You :) I have a lot parallel things going on (like, for example, building a TV for myself, check my images portal), but try O-Scope’s advances is one of priorities. Thanks, Rexnanet!

Mon Feb 06, 2017 1:14 pm

The MCP6S22MCP6S22Аналоговые, логические и силовые компоненты…e Smile ) – vols/div (modified to show “50mV”…”100mV”…”1V”etc only zoom factors. The MCP6s22 will come latter so will have to make some adjustments…) Still to do: – dual channel (…$10 O-Scope revisited looks pretty useful, I may have to have a play with that. What clamping are you intending to do in the front end to avoid blowing the poor thing up?

ImageMSP6S22 Single-Ended, Rail-to-Rail I/O, Low Gain PGA

Mon Feb 06, 2017 1:42 pm

ahull wrote:The MCP6S22MCP6S22Аналоговые, логические и силовые компоненты…e Smile ) – vols/div (modified to show “50mV”…”100mV”…”1V”etc only zoom factors. The MCP6s22 will come latter so will have to make some adjustments…) Still to do: – dual channel (…$10 O-Scope revisited looks pretty useful, I may have to have a play with that. What clamping are you intending to do in the front end to avoid blowing the poor thing up?

Mon Feb 06, 2017 1:52 pm

I will just put diode to “+” and diode to “GND”, at input. And, MCP chip on a panel, for quick replacements after explosions :))) (i have MCP6S21MCP6S21Аналоговые, логические и силовые компоненты…pists) could adapt from that device: input stage with cheap programmable gain OpApm ( MCP6S21 ). Other opamp (any Rail-to-Rail) in that schematics is for moving displayed graphic…$10 O-Scope revisited DIP case). Maybe this schematics can be used directly?
http://forum.easyelectronics.ru/downloa … &mode=view (part “1” of picture)
That lower opamp is used for moving signal up/down on the screen, Can be omitted, the C4 should be shorted. If this opamp is used, it can be any Rail-2-Rail.

Mon Feb 06, 2017 2:28 pm

Yep, I think that that schematic seems ok. Adding the diodes and it’s done.

I think that adding VCC/2 on that 100K resistor (where the opamp is connected) will allow us to have + and – voltage measuring instead of only positive.

So maybe this schematic can be of use :) Thanks!

Mon Feb 06, 2017 3:23 pm

rexnanet wrote:… So maybe this schematic can be of use :) Thanks!

Mon Feb 06, 2017 4:33 pm

It’s more like a “Bluetooth all in one tool” :) with signal generator and all…

It has an Android app and a PC version?

Edit: Just saw it, yep, I remember now :) looks good.

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