This part is all about completing the pre-requisites. We've started with the board assembly in Part 1 here, and to proceed with the application development, we need to put the board together (which requires some soldering) and flash the Meadow OS to it.
To complete this step, we would need the following:
1 Meadow board (aka 'base')
1 Wooden Wilderness Labs protoboard (or breadboard)
2 Blue female header pins
Out of the box, the baseboard comes with a protective skin cover to protect the surface from dents and scratches. If you already pealed the skin cover from it, we can start with Step 2, i.e., soldering Meadow header pins.
For this step, all you need is a pair of blue header pins and an F7 Meadow board. Before we begin, let's talk about the tools we'd require. You'll need a soldering iron (only this time, as assembling a fully functional prototype won't require soldering as such). Any soldering iron would do. I've got a relatively cheap one here, and the benefit of it is an adjustable temperature knob. This is something you can buy on Amazon, and I'll leave the link below in case you need one. Some people also use a soldering fume extractor, and even though it's not that expensive, just to make sure you don't inhale toxic fumes, make sure you do the soldering in a properly ventilated room.
Next, soldering iron tip cleaner. Once again, to keep the expenses low, you can simply use a stainless steel sponge (which can be purchased in a dollar shop) or a piece of sponge that comes with the soldering kit, just like in my case. To prepare it, it's enough to soak it in water. Having a lead-free solder is important, so it's not toxic. Soldering flux paste is not mandatory, but if you solder a lot, you can get something like the one I have (the link is in the references below). A heat-resistant surface to protect your table is a must. You can simply use a piece of plywood or a silicone mat (the link is in the references below). They're pretty cheap, but if you don't solder a lot, no need to invest too much.
To start, let's set the soldering iron temperature around 350°C (of 650 degrees Fahrenheit). Higher temperature is risky as you can damage components on the board. You can raise it as you get better at this. Once the soldering iron is warmed up, clean and tin the tip.
Next, we need to place our components in a place (simply put the blue header pins through the holes on the F7 board). Let's apply some soldering flux using a watercolour brush. Brush it on flux and apply to the pins on the other end. This technique makes soldering a lot faster and smoother, and there's less of a chance of overheating the components that are temperature sensitive. Heat the pin of the headers, then apply some solder near the tip, and it'll start flowing. Make sure there's enough solder to fill in the hole and leave a little pyramidal mound, but not so much, so it looks like the one in the video below. Soldering deserves a separate video, and there are plenty available on the Internet.
In this step, we'll assemble the board and make it ready for prototyping. Make sure the baseboard is properly positioned (mind the battery connector on the Meadow board and the orientation of the breadboard). Put each screw in the corners of the Meadow board with one nut, so when placing it on the base, it won't get in contact with it. Next, fix the Meadow through the protoboard and use the remaining four nuts to hold them together firmly. In addition, you can get metal fasteners and screw them in the corners of the baseboard so it can sit flat on any surface (the fasteners are not included with the kit).
If you assemble computers often, you may have some spare parts like screws and fasteners. I have prepared four of each, and attaching these to the board will give it a more finished look:
Next, we'll be deploying Meadow OS.
All the commands below are only applicable to the Windows system; if you work with MacOS X or Linux, please use the links below the video to find respective commands for your operating system.
When you start working with the Meadow board, it'll need to have the latest Meadow.OS flashed to it. Pre-requisites for Windows are simple:
To flash Meadow OS, 'dfu-util' is required. However, the default Windows USB driver for ST devices is not compatible with dfu-util, so it needs to be replaced. To achieve this, we can use a tool called Zadig:
Connect Meadow board in bootloader mode (to enter bootloader mode, hold the BOOT button down, press and release the RST (Reset) button, then release the BOOT button)
In Zadig, click Options --> List All Devices
Select STM32 BOOTLOADER from the drop-down menu
Click 'Replace driver'
Next, we need to install (or update) Meadow CLI and dfu-util:
dotnet tool install WildernessLabs.Meadow.CLI --global
meadow install dfu-util
Download OS and network binaries:
meadow download os
Flash Meadow OS:
meadow flash os
If this way doesn't work, you can try connecting to a serial port. While Meadow board is connected to your PC, open 'Device Manager' and find the 'Ports (COM & LPT)' section. The one you need is called 'USB Serial Device [COMXX]'. Memorize it and use the following command to bind it:
meadow use port COMXX
Once Meadow OS has been deployed to the board, we can start working on the app that can be deployed. The last step in today's tutorial would be installing VS extension for Meadow. Open Visual Studio (2019/22), depending on what you have installed. Go to Extensions --> Manage Extensions. Click 'online' and search for Meadow. Once installed and restarted the VS, you should be able to see the new project type called 'Meadow'.
Ok, guys, we're pretty much done with pre-requisites. In the next part, we'll start assembling our prototype, which is the 'temperature monitor', as well as develop and deploy the app and see it working altogether.