Introduction: Graphical Current Analyzer With Adjustable Voltage Source 2.0

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A while ago, I designed this device. I then built a new and improved version that is cheaper, smaller, and simpler.

The ZK-4KX, with its display of current and voltage in the old version, is actually a redundant component. Current and voltage are already shown in the display above the diagram, so it is sufficient to use a DC-DC step-up/down voltage converter without own display. This also eliminates the need for the additional step-up converter that was necessary because the ZK-4KX module switches off immediately as soon as its input voltage falls slightly below 5V.

Supplies

  1. 3.5inch display with Raspberry Pico connection (link)
  2. Raspberry Pico (link)
  3. Sensor INA219 (link)
  4. DC-DC step-up/down voltage converter XL6019 (link)
  5. Potentiometer (link)
  6. Switch (link)
  7. Push button (link)
  8. Connectors (link)
  9. USB port (link)
  10. Diode (e.g. 1N4001)
  11. Wires

Tools

  1. Soldering iron
  2. 3D printer
  3. Electronics pliers
  4. Screwdriver
  5. Hot glue gun

Step 1: Characteristics

  1. Supply: USB C
  2. Output Voltage: 1.2V - 35V
  3. Max. Current: 1.5A
  4. The device is switched on using the left switch.
  5. To perform a reset, briefly press and hold the button on the right.
  6. The output voltage is set using the potentiometer at the bottom right.
  7. The load is connected to the terminals at the bottom left.

Step 2: Printing

The housing is now considerably smaller and the recess for the ZK-4KX module is missing.

Attachments

Step 3: Assembly and Wiring

The DC-DC step-up/down voltage converter module used is normally adjusted via a potentiometer on the circuit board. I removed this potentiometer and measured the range it covers. I then soldered on a potentiometer with the same value (10K ohms) that can be installed in the housing.

Step 4: Software

Source code: github


For display control the TFT_eSPI lib is used, for the use of the mentioned display, uncomment the following line in "User_Setup_selection.h" in the TFT_eSPI library folder:

"#include <User_Setups/Setup60_RP2040_ILI9341.h> // Setup file for RP2040 with SPI ILI9341"