Sample rate:
While the maximum sample rate of 1 MHz is limiting the scope still has a lot of uses such as:
- PWM
- Power supplies
- look at serial data *(there are some issues with the single-shot capture)
One of the things that scope is unable to do is to look at colour PAL TV signals.
(With a colour carrier of about 4.4 MHz)
However at the same time my microcontroller (executing instructions at 4*4.4 MHz) has great difficulty
generating them.
Voltage range:
The scope has a reasonable voltage range.
- However I had difficulty when looking at the signal between a switch mode power supply
and ground (as it was at about 90v AC)
- A 10 times probe may solve this issue
Trigger:
- The trigger setting works reasonably for the automatic scan modes
- I have been unable to get single-shot capture to work properly.
- This should be fixable in software
Interface:
The trigger settings (sensitivity / slope) are on the opposite side of the screen to the trigger level.
This makes it difficult to adjust the trigger settings quickly.
- This should be fixable in software
Micro SD card
- After a lot of messing around I have been able to get the DSO nano to load / save files from a 2GB card and have been able to use USB to copy files from/to it (and format it)
- I have been unable to get the micro sd card to work with the publicly available source code (v1.1) (it only works with firmware 2.1 which is yet to have the source code released)
Other:
Durability / Casing:
- The casing looks like it should do a good job of protecting the device.
- My DSO nano had a broken screen in less than a week (though I am sure there are
plenty of people that have not had any issues) - it should be noted that Seeed Studio
provides replacements parts at reasonable prices.
- the back part is held on with a kind of double sided tape
- unfortunately it also sticks to the lithium polymer battery casing which I don't think is a good idea
Software:
Bootloader:
- The DSO nano has a bootloader which appears to do a good job of ensuring the device
does not stop working (get bricked) during upgrades.
- Code:
- One of the main reasons I purchased the device was its ability to be programmed.
- The code is rather messsy:
- a lot of global variables that are defined in header files)
- Hard to change the interface in the original code (each item has
hard coded which item came before / after it. Additionally the
direction of the controls (vertical / horizontal to change the value was hard coded)
- Use of too many brackets and without spacing.
- Bad variable names
- For example when decreasing the trigger level the code has:
"if((Key_Buffer==KEYCODE_DOWN)&&(v1>(MIN_Y+5+Item_Index[TRIG_SENSITIVITY]))){"
which unfortunately has a bug in it - "v1" is used instead of "vt" (voltage trigger)
as a result the trigger can be moved down, off the grid and passed the bottom menu.
(in firmware v1.1 the screen goes yellow, while in the new version the trigger wraps around
to the top of the screen)
- Unfortunately the newer version of code has not been released
(apparently it contains some proprietary code which can't be released)
- A version is planned to be released where the application code will be relased
without the library code.
- The details on what parts will and won't be relased have not been given.
Bag:
The DSO nano has a nice looking bag to keep it in
Box: The DSO nano comes in a nice looking box
Things to be considered for feature version of the product:
Bag:
The bag could be improved by adding a pocket for the probes to go in
Channels:
Having only one channel is limiting. However the planned version will have two channels.
Probe not in alert:
It would be useful if the scope could detect that the probe is not plugged in
Shipping:
Slow - it took 14 days from when I placed my order for it to arrive.
- There is a more expensive shipping option available but it is about $50 more.
- It would be useful if more shipping options were available.
