DSO NANO - how we users can impact next hardware design !!!

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EternityForest
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Re: DSO NANO - how we users can impact next hardware design !!!

Post by EternityForest » Mon Apr 19, 2010 4:40 pm

I Have a few ideas. I really like the idea of using those unused pins. a function generator would be great.
and spectrum analyser would be of use to many, especially those in audio feilds. but i really think one of the best things you could add is a mini serial terminal. so many MCU projects send debug info over serial. in its current state you could just change some software, but i don't see why there couldn't be a 2-way link. especially if it worked with SPI, which is used is so many projects. with 2 way communication(even if it was based on a very slow keypad where you scrolled to each letter) you could configure stuff on the fly that might otherwise require dragging a laptop or adding extra wasted stuff to your project, like switches.


This project has the potential to be a lot more then a normal dso with good software.

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Re: DSO NANO - how we users can impact next hardware design !!!

Post by kamilion545 » Wed May 12, 2010 12:35 pm

Seems simple to me -- how about adding the Openbench Logic Sniffer FPGA design as the probe backend? Then you've got a quite righteous portable... well... anything kit!
And as for the reconfigurable nature of the FPGA, well, let's just say some folks will come up with clever & interesting hacks for a portable cortex+spartan3. (Portable Bus Pirate?)

Capture 50MHz+ waveforms on 32 channels
* 200Msps captures up to 100MHz waveforms on 16 channels
* 100Msps captures up to 50MHz waveforms on 32 channels

16 buffered channels, 5volt tolerant
* M74LCX16245DTR2G transceiver tolerates voltages from -0.5V to +7V.

Why struggle to implement a 2 channel upgrade when you have ready access to an inexpensive 100Mhz 16 channel via serial port design?

Do it. Do it. Slaughter your competition with a $139 16 channel 100Mhz NanoDSO/L. :D

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Re: DSO NANO - how we users can impact next hardware design !!!

Post by rmhulle » Tue May 18, 2010 12:19 pm

I think it can fit in a "iphone" case, with 4.3" screen better to see and more internal space, but must be dual channel scope capable of doing FFT, and x-y tracing and if its possible add a kind of "SUMP + bus pirate " portable interface, possible it will have less channels but only the 16 buffered channels are good for me. Lol

technically and omap35xx ( ARM A8 + DSP CS64+) + Spartan3 are a fu** good "plataform" to make this work... But our tool won't be less than U$150, nevertheless I think It Will Worth this value.

but now I'm thinking, what type of connector to use to bring out the channels of the sump + pirate bus, or How to doing it?

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esp
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Re: DSO NANO - how we users can impact next hardware design !!!

Post by esp » Thu May 20, 2010 8:09 pm

:shock: :shock: :shock:

I guess it is a HUGE mistake if we have overlooked this post! Thank you so much for posting the ideas, which are really beyond our wildest internal brainstorming. Current DSO nano is more a prototyping level device, It will be our responsibility and top priority to improve such be-loved product with community wit!

We might not be able to consolidate so many wonderful ideas into one ultimate super mega DSO, BUT it would be more fun to brew a basic portable platform with vast extensibility. By adding an efficient and stable API, you could easily modify and even load additional apps to extend the software functionality. We will create some wiki and SVN to host/Sponsor the projects for sure.

I will keep you guys posted for the schedule, and open for any other suggestions and inputs.

Thank you so much for the impacts! :)

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Re: DSO NANO - how we users can impact next hardware design !!!

Post by shazam » Mon May 31, 2010 4:41 pm

Hi all, I just got my DSO Nano v 1.3 two days ago :D. It took me a while to figure out how to disassemble it (hint use a razor or Xacto to gently peel off the front label, remove 6 small screws).

I already knew that the Battery Charger-Power Supply circuit was an issue. Yes there is a protection circuit built-in the battery, but charging with a Schottky diode and a 1 Ohm resistor will guaranty short battery life. I have designed a fix which actually cost less than the original circuit. This will require a change in the PCB. (I have tried to load this to here, but every format I try is rejected. it is available as a MS Word. doc, and PDF)

I have a question: The test waveform showing quite a bit of peaking. Why? (Capacitors C0, C5, C3A, C4A, C6A are not installed)

I have also been thinking about the input amplifier IC, TL082. This is not the best (it is really happier with more voltage on the +/- power pins, it is noisy, and it has limited bandwidth) for this use.

A differential amplifier would be much better. This would eliminate some noise and allow using shielded twisted pair wire (like that use in tie clip microphones) which would eliminate more noise. This would require that the tip and ring of the input connector be brought to the main board, which should be easy. I have some ICs in mind, one of which has programmable (serial) gain from 0 to >-50 dB.

A couple of capability questions: can you use smaller parts (i.e. QFN)? Many of the newer ICs are only available in smaller package.

Is SeeedStudio making the small PCB with the pushbuttons? It would be better to put the input amplifier there, where it can be easily shielded. Moving the amplifier here would also allow different versions (i.e. differential, AC-DC, single ended, multiplexed 2 channels, etc)

I saw a comment about storing different set-ups. This should be to the memory card (perhaps 8 memories). It would require choosing “Save Image” or “Save Set Up” when saving.

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Re: DSO NANO - how we users can impact next hardware design !!!

Post by shazam » Mon May 31, 2010 4:47 pm

Hi,

I just made a Jpeg of the files and it is attched
Attachments
DSO Nano Fix.JPG
Jpg of my document
DSO Nano Fix.JPG (109.5 KiB) Viewed 12018 times

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Re: DSO NANO - how we users can impact next hardware design !!!

Post by slimfish675 » Mon May 31, 2010 5:48 pm

Hi Shazam,

Long time ago, user manton & i commented a similar circuit in a forum thread. http://www.seeedstudio.com/forum/viewto ... 5&start=10

I think its the way to go.

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Re: DSO NANO - how we users can impact next hardware design !!!

Post by shazam » Tue Jun 01, 2010 3:13 am

Hi Slimfish,

The circuit is from Microchip and Fairchild: “Li-Ion System Power Path Management Reference Design”, document # DS51746A, 2008, pages 5 & 12. The FET – Diode combination was made by Fairchild for this specific application (disconnect battery when external power is present).

The cost for both ICs: FDFMA2P853 and MCP73832 are $0.64 USD at DigiKey.com. For reference, the LTC4054 is $1.82.

I am an older analog hardware electrical engineer, who is always amazed by the fantastic things microcontroller designers and programmers can accomplish. Also amazing is the difficulty they have with analog circuits. I am willing to help Seeedstudio with the DSO Nano, since it is a fantastic product and they are generous with Open Source activities.

Shazam

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Re: DSO NANO - how we users can impact next hardware design !!!

Post by slimfish675 » Tue Jun 01, 2010 6:50 am

Hi Shazam,

i'm also willing to help in the DSO hardware redesign. This circuit could be a nice start, as the battery charger is a weak point in the DSO nano. Probably, the only drawback of this circuit are the switching times due to capacities and the dropout voltages when the battery is low (as XC6203 needs at least 300mV@200mA) . But, i don't know if people at seedstudio are capable to test the proposed solutions (Freezing, ESP... any feedback?).

Slimfish

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Re: DSO NANO - how we users can impact next hardware design !!!

Post by shazam » Tue Jun 01, 2010 10:28 am

Hi Slimfish,

I am not sure I understand your point.

With the minimum USB voltage of 4.5 V, the output to power switch is well over 4 V, allowing adequate margin for the 3.6V supply and the two regulator ICs:XC6206P302 and XC6206P332.

When operating from the battery, as long as there is more than 3.0V from the battery, all should be good. The 3.3 V regulator would not be regulating, but the 3.0V battery voltage will still pass through. The ST uController operates at 3V. The only use for the 3.3 V is the SD card. Many SD cards will work at 3.0 V, but many will not.

The 3.6V is used for the +/- 5V supply boost regulator SP3232. This, unlike many switched capacitor power circuits, has regulated outputs, regardless if the actual input voltage. I think using this IC is a bit of genius on the part of SeeedStudio. It is also the output buffer for the test signal, with a guaranteed rise and fall time into high capacitance loads.

Most importantly, if you want to discharge the battery to near 3.0 Volts, it will have a significantly shorter life.

Shazam
Last edited by shazam on Tue Jun 01, 2010 4:15 pm, edited 1 time in total.

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