M328P transistor tester

Preface

Project video (YouTube): https://youtu.be/J4nZ0n5suDk

Firmware (GitHub): https://github.com/wagiminator/ATmega-Transistor-Tester

Original project: https://www.mikrocontroller.net/articles/AVR_Transistortester

EasyEDA: https://easyeda.com/wagiminator/y-atmega-transistortester-smd

You can compile the firmware yourself or upload a pre-compiled binary folder. The current version of the firmware can be downloaded from the original project's Github page.
Based on the above two changes, the power interface of the OLED version was replaced with the extremely advanced USB-C.
It is not recommended to make an OLED version, but an LCD version is recommended.
If you want to make an OLED version, it is recommended not to use yellow and blue for the screen.
See attachment for more information

make

1. The component models are marked on the soldering pads, so just paste them directly. If you don’t have the components on the 0805 soldering pad, you can use 0603 instead. The 14P chip locking seat can be replaced by a female header.
2. If you need a 3D printed shell, please prepare four 10mm double-pass copper pillars, 2 M3 nuts, 4 M3*5 screws, 2 M3*15 screws, and 4 M3*12 screws.
3. The burning program requires a USB ISP downloader and an adapter cable to connect to the burning socket on the board.
4. Install the driver that comes with the downloader (included CD or network disk address), go to the project source address/attachment at the end of the article and download the program from the compressed package.
5. Download and open PROGISP (the store should also provide it as a gift), select ATmega328P in the microcontroller model selection in the upper left corner, and then click on the fuse data on the right.
6. Edit the fuse data as low-bit F7, high-bit D9, and extended FC. This step is very important. Many tutorials on the Internet do not mention this, resulting in problems with the finished product. After completing the modification, click Write.
7. On the main interface, click the two options of loading Flash and loading EEPROM on the right side, select the .hex and .eep files respectively, and then click "Auto" to start burning.
8. After the LCD version is programmed, the screen prompts low voltage. Ignore it. Disconnect the downloader and plug in the 9V battery/power supply to work.
9. If no text is displayed and the LCD has a white screen or a few small squares, it may be that the LCD bias voltage is not set correctly. Take a small screwdriver and slowly adjust the potentiometer until the display shows clearly.
10. Before normal use, we also need to calibrate, otherwise the error will be large. For calibration, you need to prepare in advance a brand-new 1uF and 22nF capacitor, and a homemade short-circuit pin (try to use pure copper with a low resistivity). As shown below.
11. Connect the short-circuit pins to the test holes 1-2-3 at the same time, and then press the button to turn on the phone. Wait for the screen to display "selftest mode ?", press the button briefly
12. Wait for the question mark on the second line to disappear and when R0=12.12 15 is displayed, remove the short-circuit cap and the program will automatically continue the calibration.
13. When the first line displays " >100nF ", connect 1uF capacitors to test holes 1 and 3 , and then remove them after the test results are stable.
14. When the first line displays " 4-30nF(L) ", connect 22nF capacitors to test holes 1 and 3 , and then remove them after the test results are stable.
15. Soon the screen will display " test end ". At this point, the calibration has been completed and you can use it happily!

Instructions for use

1. After turning on the power, insert the component to be tested into the header. Each pin of the component should have its own unique socket number (1-3).
2. Press the test button and it can fully automatically measure resistance, capacitance, and inductance. For inductance and capacitance, it can also test the equivalent series resistance (ESR). In addition, it can automatically identify diodes, BJTs, MOSFETs and other components and measure their related properties. All these operations only require simply connecting the component to the test socket, and there is no need to distinguish the pin sequence. They can be distinguished automatically and the order of the pins identified . Also note that the capacitor must be discharged before testing , otherwise the tester may be damaged.
3. Just wait for the results to appear on the display.

Change log

The OLED version was updated to the second version at 2021-07-01 12:04, which improved the layout, improved stability, and fixed some known issues.