Ordered my PCBs - another easy job

Another job this week that turned out much, much easier than I expected was getting the PCBs ordered for the Bluetooth chord keyboard I’m making.

When I made the original chord keyboard PCBWay reached out to me with an offer of a sponsorship of my next board, which I’ve only just taken them up on. I added the PCBWay plugin to KiCad and ran it to see what happens. What happens is that all your design files get sent to PCBWay, their site opens up and within a few seconds you have a price for the job. All I ended up having to pay was for quick delivery - because I’m an impatient sort. The boards arrive next week and I’m rather excited about this. It turns out that getting a custom PCB made is affordable and easy. I can see me using this service a lot in the future. And I’d really like to have a go at having a PCB made and populated.

The latest version of KiCad lets you put artwork and text on your PCB. I really think everyone should have a go at making their own boards. You might not put much circuitry on it, but you could make it look very pretty.

CheeseBox with added OLED

I thought it might be fun to add an OLED screen to the CheeseBox when we made the printed circuit board. I’ve just soldered one into place and written a little driver for it. I rather like the look. Now I have to design a box and some buttons.

The wire is there to bypass a component that it turns out we don’t need. I’d added a level converter to take the 3.3 volt led signal up to 5 volts, because sometimes the Neopixels that we are using prefer this level. However, they seem to work just fine without it.

If you’re wondering what the back of the board looks like, and just how badly it is possible to solder a PICO to some pads on a PCB, then you can see the answer above…..

Working Surface Mount PCB

Thanks to some sterling rework by number one son I now have a fully working PICO MIDI CheeseBox on a PCB. It isn’t as tidy as it could be, but it works. I wasn’t expecting this for my first attempt. Kudos to Brian for a fine design.

We tested the board by soldering wires onto connections and using an external PICO device to drive it. If I was re-designing the board (and I will) I’d add some test points so that we can inject signals to test the board without having to solder the PICO on the back.

Baking with Surface Mount

This was the kit. The tweezers were very useful.

Today we got around to actually using my little oven. I’d bought a syringe with solder paste, some tweezers, a bunch of switches and a bunch of leds to solder in place. First step was to solder put solder paste on all the connection pads. This involved squirting the paste out of the syringe onto the board, and then using the tweezers to place a component on each pad. Pro-tip, hold the syringe like you were going to stab someone with it, and then use your thumb to force out the solder. There’s a delay between you pressing the plunger and the solder coming out, so give a quick pulse of a squeeze and then wait for something to arrive at the end of the needle. If you squeeze continuously you get a stream of solder, and you don’t want that.

I was a bit stingy with my solder paste, which meant that I never got the magical “surface tension” moment where the components swing into place. Instead mine drifted around a bit.

I also got a temperature gun to check the temperature of the oven plate, but this didn’t work well because the cover is shiny. In the end we just set the temperature to 170 degrees and popped the board on for 20 seconds. Stuff melted, but there was a pleasing lack of smoke and funny smells.

This is what it looked like when it was finished…

The image above might not be correct. Actually it looked pretty tidy and all the components were stuck on the board. Next step is to solder the PICO on the reverse of the board and then test everything.