JYE Tech DSO150

There is now (Sept. 2017) a low cost (18 EUR) Digital Storage Oscilloscope (DSO shell) from company JYE Tech available, e.g. banggood.com, search for Product ID = 1093865.

/!\ you can magnify the pictures (and download) with a mouse click on it.

attachment:DSO150_DSC07450.jpg

Specifications

Modifications

In order to make the DSO more useful, three modifications are made.

attachment:DSO150_USB-UART_DSC07467.jpg

Rechargeable Battery Pack

On Ebay.de you can buy a 6 x AA battery housing (ID number 162434646097, 1.6 EUR) with 15 cm wires and an ON-OFF sliding switch. To connect to the DSO150 you need a DC plug 5.5/2.1 mm (e.g. ebay.de ID no. 152190640539, for about 10 pc. 2 EUR).

/!\ Because of the low voltage (7.4 V) you need to short the inverse-polarity protection diode. See the picture on the right for the wiring. The voltage regulators 78L05 need minmum 7 V for the voltage regulation. So, be careful to do not inverse the polarity of the power supply wiring.

USB - UART Converter

In order to allow a firmware update, or to capture waveform data via USB connection (needs toshi firmware 60B), you need to adopt an USB-UART converter. Fortunately you get on ebay.de (ID no. 381765079624, 1.15 EUR) a little module which just fits into the DSO150 housing, and has on the data lines the necessary 3.3 V level. The USB plug is micro USB.

attachment:DSO150_jumper_DSC07463.jpg

Jumpers

In order to make the firmware update easier, the solder jumpers J1 and J2 are routed with wires to 2mm spacing posts, see the picture on the right. I am using wire-wrap wires, because they are thin and have a good isolation.

I have mounted the posts with hot glue to the board.

/!\ Take care about the position, if you place the posts more to the right, the electrolyte capacitors of the analog board are in the way.

I have bought several units, unfortunately one of them could not be programmed (flashed).

For programming I used the freeware program stm32flash and used it under Mac OS and Ubuntu 1604.

$ sudo port install stm32flash

Read the CPU info to make sure the hardware works:

# Read STM32 Info:
$ stm32flash -b 115200 /dev/cu.SLAB_USBtoUART  # Mac OS
$ stm32flash -b 115200 /dev/ttyUSB0            # Ubuntu 1604
tm32flash 0.5
http://stm32flash.sourceforge.net/
Interface serial_posix: 115200 8E1
Version      : 0x22
Option 1     : 0x00
Option 2     : 0x00
Device ID    : 0x0410 (STM32F10xxx Medium-density)
- RAM        : 20KiB  (512b reserved by bootloader)
- Flash      : 128KiB (size first sector: 4x1024)
- Option RAM : 16b
- System RAM : 2KiB

Sigrok Pulseview protocol analysis (about 3 ms after trigger (falling edge)):
TXD = PC, RXD = STM32 (DSO150), data in hexadecimal
TxD 7F     01 FE                  00 FF
RxD    79         79 22 00 00 79        79 0B 22 00 01 02 11 21 31 43 63 73 82 92 79
Data                                                       
TxD 02 FD
RxD       79 01 04 10 79
Data     Device ID 0x0410

# the flashing was made with (Ubuntu 1604):
$ stm32flash -b 115200 -v -w 113-15011-060B_toshi.hex /dev/ttyUSB0

Firmware Mod

A nice guy provides an extended firmware 60B. You can download the software from toshi with source code. The benefits are:

attachment:DSO150_gnuplot_qt.png

Waveform Visualization

OK, you can download the waveform data, but how can you visualize it (see screen shot on the right)? The necessary steps are:

  1. Capture the waveform data to a text file.

    • Start the program first, waiting for the data.

    • Push the ADJ button for the start of the data transmission.

  2. Convert the waveform data to a .csv (Comma Separated Values) file.

    • Take care to localize the decimal point ("." or ",").

  3. Visualize the .csv file data with the program GNUplot.

    • Take care to include the actual Date & Time in the plot.

I liked to use a software which is cross platform (Linux, Mac OS, Windows), so I decided for Python.

The five major tasks in the software are:

  1. Wait up to 60 seconds for the start of the data transmission.

  2. Read the data into a list (real time), then write all into a text file.

  3. Read the data file, then calculate the time row, localize the decimal point and write the .csv file.

  4. Prepare a parameter file for program GNUplot. Add Date & Time.

  5. Call GNUplot with the parameter file.

    • The terminal command line looks like:

        $ python dso150-p23.py -pd
        # option -p means capture data and write a .csv file
        # option -d means plot data

The program can be seen and downloaded here.

GNUplot shows one goody in the lower left corner of the plot. It is the X-Y position of the mouse pointer in the coordinate system, in application values, in this case X=Time and Y=Volt.

GNUplot cross platform

GNUplot can be installed cross platform. The best font quality, which works on all platforms, can be achieved with the graphic library QT5. Installation:

$ brew update
$ brew doctor  # check for errors

$ brew install gnuplot --with-qt
or
$ brew (re)install gnuplot --with-qt  # in my case gnuplot was already installed with X11
==> Summary
­čŹ║  /usr/local/Cellar/qt/5.9.1: 9,019 files, 278.0MB

$ sudo apt-get install gnuplot5-qt  # version 5.0

Python cross platform

/!\ In order to use the USB - UART converter you need to install a driver from the manufacturer of the chip. For the recommended chip CP2102 it can be found at this Link

Today I can recommend Python 3. It is more comfortable than Python 2. I have tested my program partially also with Python 2.7.

$ sudo pip3 install  py-serial

$ sudo apt-get install python3

# Serial port library
$ sudo pip3 install py-serial

$ pip3 install  py-serial

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-- RudolfReuter 2017-10-07 13:21:29


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