Miniscope v4 - common questions
Since some of the questions (and my mail answers) regarding miniscope oscilloscopes are getting repetitive I've decided to write them down with (hopefully) up-to-date and complete answers.
What and from where do I have to download?
First of all: all required binaries as well as respective source code can be directly downloaded from this site - if you can't find them try scrolling pages down, particular releases are sorted chronologically. You need miniscope GUI main executable (miniscope v4), DLL library that handles particular device (most likely available on page related to this device, eg. miniscope v2d) and device firmware (again - from device page). If there is no separete bin download, then most likely compiled DLL or bin/hex file is placed inside source archive in Release directory. DLL has to be copied to miniscope v4 device directory to appear on available list. Some of the devices require also custom USB driver (libusb).
Can I connect my oscilloscope with ethernet/parallel/... port?
Most likely yes. Interfacing with new hardware requires writing new device DLL though. Reusing existing DLL code as template would be helpful. Most of DLLs are built (same as GUI) using Turbo C++ Explorer, but virtually any compiler should do the job. For starters, there is Code::Blocks/MinGW version of miniscope v2c DLL.
What signal frequency can be handled by particular hardware?
As a rule of thumb useful signal frequency range is up to 1/10 of sampling frequency, so eg. 462kSps miniscope v2c would be useful for signals up to ~50kHz. Don't believe in advertisements - large analog bandwidth would not allow to beat this limitation and equivalent time sampling is useless most of the times. If you are going to work with repetitive signals when equivalent time sampling may be usefull you may be better with analog oscilloscope. Beware also of sound cards limitation - cutting off DC component that would be often more important than top frequency.
Miniscope v2b/v2c/v2d: can number of input channels can be increased?
Yes, at the cost of effective sampling frequency per channel. Second thing that needs consideration is that sample time (for sample & hold buffer) may also need to be increased or input source impedance for ADC may need to be decreased in order to keep good channel separation. This would not be a problem if separate ADCs (or at least sample buffers) would be available for each channel.
Miniscope v4 (GUI) does not require any changes when increasing device channels number.
Is miniscope v2b/v2c/v2d available for sale?
No (at least not on noticeable scale). Most of the code is licensed under GPLv2 thus commercial usage is not prohibited if you'd like to manufacture and sell it.
Would it be possible to increase sampling frequency?
Yes, but it would quite likely increase cost and make it not competitive with already available commercial products. Miniscope v2b/v2c/v2d are in kind of "sweet spot" - they are limited by USB full speed bandwidth but on the other hand their sampling buffer sizes are quite large and their recording capabilities (at full speed) is limited only by used recording file structure (4GB per file). In this area I believe they have no competition, often beating their price by the order of magnitude.
I'm trying to keep and eye on the market and hopefully microcontrollers with the right feature combination (fast ADCs, high-speed USB, DIY-friedly small non-BGA package and availability) would eventually arrive for new miniscope version.
Miniscope v2c, v2d: what value use for C10, C12?
These capacitors are used as a anti-aliasing filter elements (limiting analog bandwidth). If you are unsure how to choose value I suggest skipping (not mounting) them.
Miniscope v2c, v2d: how to change voltage range?
Change input divider resistors value to get desired ratio between oscilloscope input and microcontroller ADC input voltage range (0-3.3V). Change fSens array value (sensitivity per bit) in DLL source code to match and rebuild DLL.
If you'd like to add switchable signal conditioning to miniscope v2c or v2d - take a look at v2b. Another circuit worth considering is one used by DSO nano.