2014-06-17

wireless power - status update 2

So what happened in the last two weeks? As already mentioned, I finalized the PCB and send it away. I did go with Würth in the end. They were not the cheapest of the lot, but provided the most bang for the buck. I got 5 day manufacturing time (and since they deliver with courier, probably even from Germany, delivery also takes only one day). Also, they did not charge extra for silkscreen or solder resist (as may happen with cheaper manufacturers). And last but not least I got Ni/Au plating for still the same price, which is not only better for long-term usage, but also better than HASL for SMD soldering. So I send the board files off to WEdirekt (no need to convert them to Gerbers), and thanks to Simon Leuz I even got a 10 percent rebate

And lo and behold, the board arrived today. Opening the envelope reveals this:

The properly packaked PCB frpm WEdirekt

Looks strange, I did not remember to order a white PCB… But further unwrapping reveals the real PCB, and it looks really nice:

top side of the PCB - with a rules for comparing its size

bottom side of the same PCB

The silkscreen looks different - it seems to be color-less, and is matte finish. Given more time to look at the options of Eagle I should have made the vias tented. I do not need to solder on them (OK, maybe use them for probing signals), but there are many places where the silk screen runs over the vias (the board is populated rather dense). Also, I should have made the silk screen a little bit thicker (the font size is OK though), so it would be more readable.

While waiting for the PCB, I also made my Farnell order (finally…). I waited so long to be sure that I really could order anything I needed for the project. (And I really found some crucial part in the last week that I did not have available). Farnell was little bit faster than Würth, but they just had to package all the things up. This how a Farnell order worth 200 EUR (that made 60 items…) looks like:

A large farnell order - 60 parts...

It came actually in four different parcels, since parts of it came from UK (the rest from Belgium), and the etching chemicals I ordered are treated as dangerous goods and came in separate parcels.

About one third of the stuff I ordered went into this project, which means that my project box with all the stuff in it now looks pretty crowded:

my project box for the wireless charger station

Until now, I discovered two errors I made. First, I ordered two type of resistors in 0603 package where it should have been 0805 (as the footprint is on the PCB). Second, two resistor footprints on the PCB are 1206 where they should have been 0805. Both are fortunately not fatal (the affected resistors are not the same ones), and the resistors should fit nonetheless (though soldering 0603 components by hand will get tricky).

I also worked on the enclosure for the transmitter - after all it needs to be handled by my son. But since its now finished by now, I did not take any pictures (it just needs some final touches to be ready).

So I will try to finished the enclosure today, and then start populating the PCB. Since I did not prototype all of the parts of the circuit, I will start doing only parts of the PCB, and then test it to be sure it works as intended (and without destroying other parts, maybe).

Posted by Hendrik Lipka at 2014-06-17 (Google)
Categories: electronics projects contests