MERG Logic Probe Kit
This kit was obtained from the members only Kit Locker on the Model Electronic Railway Group website.
Breaks were made in the stripboard using a 5mm drill, according to instructions. The components were then soldered in place. The board was tested at this point using a 5V power supply and found to be working.
Next a pair of crimp terminals were modified and soldered to the perf board to act as +ve and ground connections. Extra gaps had to be added to the stripboard so that the new terminals did not short out adjacent tracks. Then a male to male DuPont connector had one plug removed and the resulting bare wire was soldered to the perf board, with the end attached to the remaining plug acting as the logic probe. The result can be seen in the following photograph:
The adapted board was once again tested successfully. At this point it was decided that the kit would make a useful tool to complement my much larger, commercial logic probe. Consequently a case was designed in TinkerCAD and was 3D printed on my Bambu Labs A1 3D printer using Bambu Basic PLA:
The circuit board was then inserted into the case. Strain relief for the probe lead was provided by super-gluing the lead in place where it exits the case. The two parts of the case were then super-glued together.
The assembled probe was tested and found to be working as expected. When the logic probe is not connected then both LEDs glow. When the probe is connected to logical high then the green LED is lit and the red LED is extinguished. The opposite is the case when the probe is connected to logical low.
Finally, some red electrical tape was attached below the LEDs and above the +ve terminal. The tape below the LEDs was annotated to indicate which LED is lit when high and low logic levels are detected.
The final assembly can be seen in the following photo:
In summary, this kit went together easily and, after the terminals and probe were attached and the enclosure was constructed, made a useful addition to my metering toolbox.