@gohan Yes, you are right, this is done by cnc router.

@scalz Thanks for your answer. Assembling a sensor by my own is not really what I want (or am able to achieve). So buying assembled sensor is the only option for me. Thus probably commercially available sensors will fit better, since they can use the scaling factor of assembling a huge amount of sensors. My HA is driven by cost to performance ratio, where cost also include somewhat the amount of time to invest and performance also covers things like the ease of use, appearance etc. Interesting to hear though that those commercial sensors might be less premium regarding the part quality, battery life etc.