Xprotolab - Miniature Oscilloscope and Waveform Generator

[ganzziani]

I'm developing a fully featured, low cost, MSO. Schematics and HEX files available if you want to build your own unit.


The Xprotolab is the first mixed signal oscilloscope with an arbitrary waveform generator in a DIP module. It measures only 1.6" sq. inches, it can be mounted directly on a breadboard, or can be used as a component on your next embedded project. The Xprotolab can also be used as a development board for the AVR XMEGA microcontroller.

General Specifications:

• ATXMEGA32A4 microcontroller: 32KB Flash, 4KB SRAM, 1KB EEPROM
• Graphic OLED display 0.96", 128x64 pixels, wide viewing angle
• Module size: 1.60" x 1.00"
• PDI interface
• 4 tactile switches
• Micro USB connector for power (Software USB will be a future update)

Oscilloscope specifications:

• 2 Analog Inputs, 8 Digital Inputs
• Maximum Sampling rate: 2MSPS
• Analog Bandwidth: 320kHz
• Resolution: 8bits
• Input Impedance: 1M?
• Buffer size per channel: 256
• Max. Input Voltage: +/- 10V

AWG specifications:

• 1 Analog Output
• Maximum conversion rate: 1MSPS
• Analog Bandwidth: 66kHz
• Resolution: 8bits
• Low output impedance
• Buffer size: 256
• Max. Output Voltage: +/- 2V

[DJPhil]

Very interesting, and cheap too!
Looks like the sort of thing I'd toss in the glove box next to my travel meter, just to always have one handy.
Well done, I hope you'll continue to tinker with the design.

[tyblu]

Nice project -- have been following your progress for a while, now. A question: what is the relationship between the AWG maximum conversion rate (1MS/s) and analog bandwidth (66kHz)? Is it limited by a power amp ("low output impedance")?

[ganzziani]

what is the relationship between the AWG maximum conversion rate (1MS/s) and analog bandwidth (66kHz)? Is it limited by a power amp ("low output impedance")?

The 66kHz is just a lowpass filter that I have on the output amplifier, this is to make the discrete steps from the DAC look more continuous. I'm actually going to decrease the filter frequency to 44kHz to minimize unique parts on the board.

To be able to create distinguishable waveforms, I decided to have a minimum of 32 samples per cycle. So, with 1MSPS, the maximum frequency that I generate is 31.25kHz. This could be changed to output higher frequencies, but then the triangle wave would look similar to the sine wave.

Also, with the 1MSPS rate from the microcontroller's DAC, the maximum output frequency is 500kHz, the next possible frequency would be 250kHz... So there are big gaps if using the highest frequencies.

[CafeLogic]

I love the XMega but I have already been bitten by it once. One day digi-key has 3000 in stock, the next day it's like hens teeth. Hopefully it will be better for you.

It was that same one too, the 32A4.

[edy]

I picked up an Xprotolab and Arduino Uno R3 from Spikenzielabs in Montreal.

Has Dave done a hands-on video with the thing? Anyone send Dave a sample to play with? I'd like to see his take on this device!

[alm]

I expect him to call it a toy bordering on useless. Look at his opinions on the DSO Nano or PC-based scopes, and take into account that their specs are orders of magnitude better than this product. Expect the word 'wank' to be thrown around a lot.

[edy]

Thanks for the reply. I watched Dave's EEVBlog #86 and read his DSO Nano thread and now that I feel like a total noob for buying one, following Dave's suggestion to ask someone on the forum, if they have an old analog oscilloscope laying around collecting dust if they wouldn't mind letting me know. :-) I'm in Toronto, Canada.

[alm]

Posting a new thread about getting an analog scope in the buy/sell/wanted thread would get you more exposure. I would put 'Canada' in the title, since shipping analog scopes overseas is expensive.