Today I show you a little bit longer video about the assembly of the component side of the snow flake panel.
Compared with the very small 0402 LEDs (1mm x 0.5mm) on the front side, the component side contains just regular 0805 resistors and capacitors.
The first part of the video shows how I apply the solder paste using a metal stencil. I use a system called “eC-stencil-fix” from Eurocircuits. This is basically a set of plates with metal knobs to perfectly align the board with the stencil. With a tick in a checkbox, they produce panels which perfectly work using this stencil fix system, which is really convenient.
This is the third part of the meta-tutorial, where I talk about designing a cheap plant watering sensor. If you did not already read the first and second part, please do it now. These parts contain a lot information which lead to this point of the tutorial.
The second part ended with step 14, designing a first prototype PCB. So let us start with the next steps in this journey. This article will be the smooth transition from prototyping to the initial planing for a final design.
Step 15: Assemble and Check the Prototype
After receiving the prototype PCBs from OSH Park, I assemble one completely, including the cable and with one of the sensor plate prototypes as foot part.
Set the Fuses of the Microcontroller
The microcontroller ATtiny13A requires programming using SPI before it can be soldered to the board. There are special bits in the memory, called “fuses”, which control very basic settings of the chip. One of this fuse controls if the chip can be programmed and debugged via the debugWire protocol. This protocol just uses one single wire to program and debug the chip, bus has to be enabled first.
So I put the microcontroller into the programming adapter and connect everything via the Atmel ICE to the computer.
Here a short update on the progress with the final Outmoded Sequencer project. I did the whole assembly of the final PCB and connected everything. You can see part of the soldering process in the following video:
I accidentally cut a route on the bottom of the PCB, so I had to fix this with a short wire. It is not visible on the final device. The magnet matrix mentioned in a previous post is already securely fastened to the bottom and holds the steel balls in place.
There are only the final adjustments of the frequencies left to do. I have to tune each tone and add the last four missing resistors.