I can’t remember when was the last time I’ve made a real custom PCB to actually fit the internal shape of a model. If memory serves me right, it could be the Warhammer Stormfang and that would be around 10 years ago. But that was just a plain simple rectangle. This time, the challenge is different.
The Problem
One great thing about JLCPCB is that they can produce my PCBs in any shape. As long as my EaglePCB is able to design the board (with some help from InkScape, that is) and convert it into GERBER files, I am good. Today, I am going to show you how I am really going to design the PCB to fit into the Blade Runner Spinner model.
I love JLCPCB because they can turn my board into any shape and I am talking about shapes beyond the basic rectangles, triangles and circles. Now, with the combination of pre-Autodesk EaglePCB7.77 and InkScape, I am limited only to my imagination. This is a very important concept because this makes the custom PCB fits snugly, leaving more space for other parts of the model. For today’s post, I am going to show you how I re-design the second version of the Blade Runner’s Spinner front mandibles. It is not very detailed but the main goal is for you to understand how to create a PCB outline over a superimposed image of the part.
First, you take a picture…
Using any camera, take a nice photo of the part. If your camera has gridlines, use it to align the part until looks ‘straight’. And if possible, position your camera further away and then re-size it (or zoom in) before pressing the shutter. This is because if you take a close-up shot, the lens could distort the image and the dimensions would look very weird later on.
Using a picture to design the PCB layout solves a lot of problem when the part is too small for the conventional rulers and calipers. This not only save a lot of time, but your guesstimation would be very accurate.
There are two layers in this InkScape screen. The first (top) is the vector .svg file of the PCB shape I made from the last post. The second (bottom) layer, is the photo of the part. I had to reduce that image’s size (approx. 90 px) to fit the vector shape. Once that is done, I created additional shapes and then converted the whole vector design into the .dxf file.
Making ends meet
There is one plausible reason why the design failed; the lines were not properly linked. Imagine using a FILL Tool to fill an area with a certain colour and suddenly, the whole image was flooded, thanks to an invisible gap among the lines. From the 2nd image above, it now makes sense as if the green bleeded all over the rectangular template. I am not familiar with InkScape well enough to look for and close these gaps and so, I used EaglePCB instead.
20250904 Update
After cutting out the mock PCB and test-fitting onto the Spinner part, the dimensions looked spot-on. Still, it needed some further fine-tuning. As for the 1/8W through-hole resistors, I am still on the fence on this. They might solve the temperature issue but makes the PCB bulky. On the other hand, I can use them as part of a model’s interior details. Another issue is that once the PCB is in place, it will prevent the mandibles from swinging upwards into ‘Car Mode’.
20250905 Update
I hope to refine the design as close as possible but not to close as to being anally accurate. Once the shape is confirmed, only then would I start to re-design the circuit which is more of a tougher challenge as I have to fight the auto-router most of the time while placing the 1/8W resistors so it could conform with the Spinner part. And yes, I would thin the board to 0.8mm instead of the 1.0mm.
This is the second attempt which looks promising. I am not too worried about the gap (yellow) anymore. This image confirms the new PCB layout is good to go. Next would be arranging the components for the board.
