If you want to go fast I suggest you to check some guide made by other users:

• Full Article for the first video: link
• Project material can be found here in Github, other resources at the end of this page
• It is suggested to join the Telegram group to get more info and support

Hardware

To build the HS402-WiFi oscilloscope you can choose among these 2 options.

1. Easy Built

You need:

• HS402 oscilloscope (built with PCB V2.0 or PCB V3.0) with Firmware ver. ≥ 1.7
• ESP32 Development board (one with ESP32-WROOM first version or ESP32-WROOM-32D), connected to STM32 as following and flashed with latest ESP32 Firmware. Flashing instructions here.
• You can also use a PCB adapter created by Mikael to connect the ESP32 and STM32 together. Look at this project here, usage video here.

2. Full Built (with PCB v3)

• A compact built using PCB v3 which integrate all the components, including the ESP32-WROOM chip
• PCB v3 is composed by 2 parts that need to be separated. Then main PCB is for the standard HS402 USB oscilloscope, the small PCB is the WiFi Module.

You need:

• Get PCB v3, split the 2 board along the separation line by using a knife on both side and the apply a pression on both side to take the 2 board apart.
• Solder all the components. A demo of the STM installation for PCB v3 is here.
• Flash the STM32 and the ESP32
• Put the WiFi Module over the HS402 long connector (top right)
• Power from BAT connector (3.6 – 5V) or from USB connector of the STM32

After just follow the User Guide to connect the WiFi configuration page.

Firmware / Software

• STM32 with HS402 Firmware ver. ≥ 1.7
• ESP32 with latest Firmware
• HScope Android app ver. ≥ 214

Powering with Battery

1. With 5V Battery Pack

• Possible with whatever hardware built

Just connect a classic phone charger to the USB port of ESP32 or of the STM32 to power up the oscilloscope.
You can also disassemble a phone charger and add a switch for power, as done in this video.

2. With 3.7V Lithium Battery

• Possible only by using the hardware Option 3 in the PCB v3

With the hardware Option 3 in the PCB v3 it is possible to power the oscilloscope directly with a 3.7V Lithium battery. You can add also a micro-charger circuit as in the following schematic. This configuration allow the lower power consumption for this device (around 180mA avg).

Resources

• Open Source Hardware Schematic for HS402-WiFi V3.0 available here.