You can check out the project on GitHub.

This board is designed for my pick-and-place machine. It might also work on an FDM 3D printer, because in my plan the PnP machine is derived from a box-style printer (for example a Voron). I am not sure yet whether that part is fully feasible.

Why I'm building this:
One day I had to place a lot of 0603 SMD parts onto a PCB with tweezers. It was exhausting. Later boards may use 0402 as well. Sending a small batch (two or three boards) to a PCBA house costs too much. I wanted to buy a pick-and-place machine, but commercial machines are far beyond my budget, so I decided to build one myself. When I looked at open-source PnP machines, most of them were flat 2D layouts. With many feeders they take too much desk space. So I decided to build a box-style pick-and-place machine from scratch. That is why this project exists.

Hardware:
The three cores are STM32H745XIH6 (MCU), XC7A35T-2CSG325C (FPGA), and V851S (MPU).

I chose this trio because I want mixed alignment: pure optical alignment for simple parts (0805, 0402, and similar packages), and a vision camera (OpenCV-style) for complex parts. I also want up-looking / down-looking cameras plus on-device AI for machine-health checks — that is why V851S is in the mix.

I am using pure optical alignment on simple parts because I want industrial on-the-fly ("flying shot") speed, and the vision hardware that can actually do that is far too expensive. Optical alignment is much cheaper, but it needs real-time performance. The machine is meant to be a box-style CoreXY so it takes less floor space (like a Voron printer). The box-type feeders work like a small parts warehouse: during a job, parts are brought down to the bottom and dispensed from there. The moving head can also travel to a zone tens of centimeters above the work platform to change tools (nozzles and other accessories). That means a lot of structure and a lot of stepper motors to control. Closed-loop steppers with the servo drive in the motor base are too expensive for me, and the cheap ones are not fast enough. An FPGA can handle that and more — I want the finished machine to be strong, not merely usable. That is how this three-core combination ended up here.

This hardware cannot run OpenPnP smoothly, so I have two approaches:

1. I reserved a PCIe 2.1 ×2 link for another board that would run OpenPnP (it sits in a PCIe ×4 slot, wired to the FPGA). XC7A35T-2CSG325C actually supports PCIe 2.1 ×4, but honestly I am not confident I can make that work yet. So I will not aim that high for now — maybe later.

2. Another way to measure component offset without OpenCV.

First, a camera detects the part (the camera is connected directly to the MPU). I have two design options; I prefer the second. Both use a small AI model to detect orientation (0°, 90°, 180°, or 270°). Everything below happens after Step 0.

Here are the actual steps (flowchart first, then the explanation):

① The nozzle picks up the part and moves to a laser light curtain near the feeder (light curtain 1).

② When light curtain 1 is blocked by the part, lock X = c.

③ When the part leaves light curtain 1, lock X = d.

④ Rotate θ degrees.

⑤ When light curtain 1 is blocked by the part, lock X = e.

However, knowing only these values is not enough to calculate the XY and angular offsets. Therefore, when a component type is used on this machine for the first time, it will go through the following steps, and the final results will be saved. 

① The nozzle picks up the part and moves to light curtain 1.

② When light curtain 1 is blocked by the part, lock X = f.

③ When the part leaves light curtain 1, lock X = g. And save |f − g|.

④ Rotate α degrees (this value is small like 0.9 degrees or smaller) and moves to light curtain 1.

⑤ When light curtain 1 is blocked by the part, lock X = h.

⑥ When the part leaves light curtain 1, lock X = i.

⑦ Rotate α degrees and moves to light curtain 1 and back to ②.

Therefore, it will go through the following steps, and the final results will be saved.

That is the general workflow. There is no need to overthink the remaining details right now—the mainboard design revolves around this concept anyway. My immediate goal is to build the mainboard first. Success or not, I am fully committed to making it, and even if it fails, I will learn a lot along the way.