PCB debugging can be tricky. For example, if we want to use an oscilloscope to measure signals of interest in the PCB, we need to locate them in the schematic and select the appropriate pad for each signal on the PCB layout to put the oscilloscope probes. This process requires frequent switching between the schematics and the PCB layouts. Moreover, our hands may not be precise and stable enough to accurately place the probes on the pads without causing short circuits with adjacent pins, which can lead to further issues. Additionally, if multiple signals need to be tested, two hands will not be enough. Probe hook clips can be used, but this often necessitates the use of extension wires that must be soldered onto the targeted pads.
To streamline the debugging process, we introduce the PCBPT (PCB Probing Tester). This innovative solution connects the schematic and the test equipment output seamlessly. By selecting signals of interest directly from a GUI, users can instantly monitor the output on an oscilloscope, significantly improving the effectiveness of the debugging process.
Machine & Hardware:
The machine is a miniature CNC machine equipped with two probes capable of simultaneous movement on XYZ axes, allowing for the measurement of two signals at once. Its design utilizes 3D-printed parts and off-the-shelf materials, ensuring ease of reproduction.
The software component of the PCBPT is compatible with Eagle-designed PCB files. A custom-designed Python program can parse these files, and extract and store the coordinates of all pads in the PCB layout design. The program can also list all signals in the design and present them in a GUI. Once the PCB is placed on the machine platform, users need to define the board's orientation and control the machine to position the probes on any pad. The program records these necessary steps for probe movement as offsets and calculates all the pads' coordinates relative to the machine's origin. After this step, users can select the signals they wish to measure in the GUI, and the program automatically chooses appropriate pads based on their size. It then sends commands to the PCBPT machine, which automatically places the probes on the corresponding pads. With the assistance of the PCBPT, users can focus solely on selecting signals and monitoring the output.
The PCBPT is a compact and efficient tool that seamlessly integrates schematics with test equipment output. It provides engineers with a new and improved approach to interacting with their designs during the debugging process.