I am an Italian in China...
Thanks also to some of you I completed the project in early April... Then I started to produce , but I encountered the usual problem of the self made PCB and soldering...
Few months ago I built myself a PICK & PLACE machine...

the results: Nice pictures of the STM32F103C8T6 I used

I live in China, and here everything related to electronics is economically and logistically accessible. The problem was to do something professional i needed the support of factories, they can take care of all the PCB soldering... But also here in China this is not a solution for prototyping and small production... so few years ago i built myself a reflow oven... However placing the SMD components on the PCB by tweezers or by vacuum pen was a nightmare... Holding the breath and squeezing the eyes... To go really pro i needed a Pick and Place machine... but... the prices for a manual one are high... and also here in China there is nothing good and affordable... I decided to build one myself ... ordering many small mechanical pieces to test... finally i was able to have a very good and affordable pick and place machine with microscope.

I think let other people benefit from my effort could be useful to many.
I built a website, there you can see many pictures of my development, and many pictures of my STM32 solutions. The stencil in China is about 8us dollar, so every time I prototype I go for the stencil....
I also made a video of the production of the PCB (picture above) using my Pick and Place machine and my reflow oven but the strategy I used may be used with yourself built Pick and Place machine tooo. this is the YOUTUBE link.
https://www.youtube.com/watch?v=RCHVMQy ... e=emb_logo
I don't know if it is allowed post link to personal websites so I won't do.
Now i'm adding to my project a gps. So I need to squeeze on that small PCB also a GPS, antenna and micro sd..... the software is almost done... I will start to redesign the PCB by Eagle soon.
If you need suggestion or info about how to do just contact me.