Low-Cost USB Oscilloscope

[T.Jackson]

Hi everyone.

In terms of actual hardware circuitry, I would like to invite you all to share your views on what just exactly would be required in order to produce a respectable USB-based Digital Storage Oscilloscope. My first initial thought is a 18f4550 teamed up with a fast dedicated ADC and 32K of SRAM. Plus, an analog front-end of some description somewhere in the equation. Is there an easier way or some form of hidden magic inside a 18f4550 or similar? Anyone accomplished a project like this?

Desirable criteria:
1. 5 MHz bandwidth.
2. Dual Trace.
3. 400V.
4. All controls adjustable via Windows XP GUI.
5. Low-cost, compact size.

Regards,
Trent Jackson

[Luciano]

Hi,

See this URL:
(Schematics of the first version of Bitscope in PDF files).
http://www.bitscope.com/design/

The used ADC:

TLC5540: 8-Bit High-Speed Analog-to-Digital Converter
Sample Rate (max) 40MSPS

http://focus.ti.com/docs/prod/folder...t/tlc5540.html
http://focus.ti.com/lit/ds/symlink/tlc5540.pdf

Price about 5 USD:
http://www.digikey.com

* * * *

If you need an USB oscilloscope: (USB powered).
http://www.bitscope.com/product/BS50/

Made in AUSTRALIA.

Best regards,

Luciano

[mat janssen]

This firma has also complete units.
I use one of them and I am very satisfied with it.

[T.Jackson]

Hi,

See this URL:
(Schematics of the first version of Bitscope in PDF files).
http://www.bitscope.com/design/

The used ADC:

TLC5540: 8-Bit High-Speed Analog-to-Digital Converter
Sample Rate (max) 40MSPS

http://focus.ti.com/docs/prod/folder...t/tlc5540.html
http://focus.ti.com/lit/ds/symlink/tlc5540.pdf

Price about 5 USD:
http://www.digikey.com

* * * *

If you need an USB oscilloscope: (USB powered).
http://www.bitscope.com/product/BS50/

Made in AUSTRALIA.

Best regards,

Luciano

Bitscope appears excellent. I like everything except for the Windows UI. Too past date. Bitscope, in terms of price is comparable to a good quality brand new 20MHz CRO. Too expensive. TLC5540 has some nice specs. Price seems good too. Thanks for bringing it to my attention. DIY USB scope for under $100 in kit form, can it be done?

Regards,
Trent Jackson

[Luciano]

Hi,

You need an FPGA to build a digital oscilloscope.

The acquired ADC data goes from the ADC to the RAM under the
control of the logic implemented in the FPGA. (The acquired
data is stored into the RAM without the microcontroller).

Best regards,

Luciano

[T.Jackson]

,

You need an FPGA to build a digital oscilloscope.

The acquired ADC data goes from the ADC to the RAM under the
control of the logic implemented in the FPGA. (The acquired
data is stored into the RAM without the microcontroller).

Best regards,

Luciano

Hi,
Thanks for your feedback on this. Do you think it would make a viable alternative in configuring a fast enough PIC to fetch data from the ADC and then place it in RAM. Something running at 48MHz should handle it?

Best regards,
Trent Jackson

[Luciano]

Hi,

You need a microcontroller with an external memory bus.
Even with an external memory bus, the oscilloscope will be
slow or better said just a toy. My assumption here is
that you need an oscilloscope for projects where
microcontrollers are involved. If you need an oscilloscope
for audio signals then go ahead, it will be fast enough.

Try to calculate how fast your oscilloscope could be.

Best regards,

Luciano