Still working hard on Spacehack, I've designed some PCBs for handling all of the bussing of the LCDs.
I have four designs. An adapter board for each of the two types of LCD and a bus board for each type of LCD. You may or may not know that Spacehack uses HD44780 character LCDs and Nokia 5510 monochrome 84x48 [I think] graphic LCDs. So I made some designs and sent them off to Seedstudio's fusion PCB service. The idea for the whole design was to have a handy, small-ish connector on the back of each LCD and then have some ribbon cables going to the bus boards which then go onto a cape on a BBB (design in the works).
I needed one of each bus card for each consoles and then an LCD adapter for each LCD.
This list was:
- 4 x HD44780 buses
- 4 x Nokia buses
- 18 x HD44780 Adapters
- 10 x Nokia Adapters
Seeed forces you to select a quantity from their list of available quantities. This meant the list looked more like this:
- 5 x HD44780 buses
- 5 x Nokia buses
- 20 x HD44780 Adapters
- 10 x Nokia Adapters
Okay, that's fine, at least I'll have spares. I've used the service before a couple of times and so wasn't surprised to find that when they arrived I had more than I had asked for anyway and so I ended up with a list like this:
- 5 xHD44780 buses
- 6 x Nokia buses
- 22 xHD44780 Adapters
- 12 x Nokia Adapters
I presume that they put extra copies on their batch where they can afford to so that the customer has spares and so is less likely to reject damaged boards as they have more than they need. In total I needed 36 boards, I ordered 40 and received 45. Not bad! This was a total of 9 spare boards, 5 of which were free.
Good going so far. Delivery times from china are slow, but for $80.87 (Which translated to £49.58) for an order this size, I can't complain.
Or can I?
Let's take a closer look at some of the boards...
The first thing I noticed was that some of the HD44780 adapters (labelled "Back-cards") were a little damaged. Take a look;
Sorry about the poor quality of the images and the lack of reasonable cropping, I took these photos with a phone and a cheap plastic eye magnifying lens.
These small chips weren't the worst of it. This PCB looked like it had a disagreement with the milling machine. A chunk of the board is missing as if something sliced it off;
Oh well. There's spares. That's not a problem.
Another minor issue was a scratch on a Nokia bus card. It hasn't gone all the way through the copper tracks but it has exposed the copper slightly. Just a minor QC thing;
Something that Seeed does with all of the PCBs they make is add text to them that includes a number. I presume that this number is how they determine which order wanted that PCB. They don't make it easy for themselves however. I have found that the numbers aren't always on the silkscreen layer. Sometimes they are on the copper layer and in one case, it was on the solder mask stop layer.
On the right here is a typical silkscreen ref number (1418y2p116587);
This photo shows a number added on to a copper layer in a place where it could as easily be placed on the silkscreen layer;
This is my favourite however, this text went on to the "No soldermask here" layer;
With this one, they had to get a little creative. The small board was a bit of a problem for getting the reference number on so they had to split it into two, interestingly, the first half of the number is at the bottom;
You may have noticed that the larger boards had different numbers. It's likely that my small boards were part of a different batch to the big ones. The colour of the solder mask is slightly different between boards with different numbers.
Another thing that I found was that the text had somehow become bigger between my eagle files and the finished product. I don't know if this is my fault or theirs but the text on the design that says "HD44780 Bus Card" fits in before the rectangular test pad. The contrast pot text also fits on the board in the design but has fallen off the end on the product. The mind boggles;
Assembling the boards was easy, the boards are of the kind of quality you expect from a DIY soldering kit.
The boards are all correctly sized and everything fits well, here is a pair of LCDs with their adapters in place and cables attached;
Here is an assembled bus card for the first three LCDs;
And the bit you all wanted to know, It all works fine with no issues at all;
And now to do a whole lot more soldering;