• 4 Posts
  • 31 Comments
Joined 1 year ago
cake
Cake day: June 9th, 2023

help-circle
  • I remember being a child and building a space station (it looked a bit like StarLab so I guess the station in general was on TV or in a book) with a solar array that shape, my parents were a little angry and asked where that shape came from. I didn’t have a clue so I basically just said I liked the symmetry. They told me that’s a "very bad shape and that I have to rebuild it. It ended up being 8-shaped, which was also nice.








  • Not sure if that helps your research. We have an (very expensive “upper 4 digit region” they didn’t tell me exactly) DJI drone (an Matrice 30T if I remember correctly) at work that has the option of operating autonomously with a base-station where it also automatically lands and recharges. The catch is it’s like impossible to operate autonomous UAVs here because of airspace restrictions (that’s why we only have the “manual” version without that base-station thingy). I’m not directly involved in the department that operates the drone so I don’t have more in depth insights but maybe that already helps a little.

    Fun fact, our military had to cancel a large and very expensive drone program because the drone (a little larger one tho) couldn’t get certified in European airspace (“Eurohawk” if you want to google that). So I’m not sure how easy it will be to hack something together depending where you are in the world and what restrictions say there.







  • Mine is the smallest one of a series of these, it has two heating elements inside.

    I don’t have it for that long but I didn’t have problems so far, I’m usually only making rather small PCBs tho. I did make some recommended modifications like replacing the paper insulation tape with a kapton tape, proper grounding and flashed another firmware.

    I did only use a small hotplate and/or a hotair station, so it seems to be definitely a stepup here 😌.


  • I was kind of afraid of SMD things in general a long time but I discovered they are (up to a certain size, 0603 is still okay for hand assembly if you’re patient) comfortable to work with. Even QFN packages are okay if you have access to a hot-air station. I did actually order an BGA sensor out of curiosity along with other things, looked at it and was like “hahaha, thanks, I probably better don’t design that thing into my circuit” (I think it’s a 5-WLCSP package).


  • Yeah I have such a small, cheap Chinese one (T962) that I modified and flashed a nicer firmware on.

    I basically populated the bottom side (with more components) first after applying solder past with a stencil, then reflowed the board. After cooling down I applied the solder paste to the upper side (with the LED) by using a small needle on a syringe (because using a stencil was too weird since the board wasn’t laying flat) but since the pads are relatively large and not that many that worked fine. Then I placed the components on that side and simply run the reflow cycle again.

    I started with the bottom side because there are no heavy components. I expected heavy parts to just fall off on the second reflow cycle so I tried to avoid that.

    At the end I manually assembled the USB connector using a regular soldering iron and tons of flux gel.




  • Thanks for your tips everyone! Here’s the complete double sided practice-board:

    It’s also the first time I tried double sided reflow, which worked nicely. I did somehow expect things to fall off but they were held in place nicely. I did the side with the larger amount of components first because there are less heavy items, reflowed it, flipped it over, populated the backside and reflowed again. The only thing I didn’t think about is that I couldn’t just use the stencil easily because of the now uneven bottom side, so I just applied the solder paste with a small needle on the syringe since there weren’t too many pads. At the end I assembled the USB connector using the tips you gave here (thanks!). I’m using a cheap (slightly modified) T962 oven and lead-free solder paste for the reflow process.

    It’s by the way a simple two layer reference design from framework computer for their expansion card system.