Tips for hobby embedded development beginners

2020-08-28

Somebody asked me to write these tips down so here is a very opinionated looong list of tips and hardware recommendations for hobby beginners based on my own experience.
There are many alternatives to the things I mention below, and there is people with different opinions, and that is all fine.

Good tools pay off and are more fun to use.
Soldering
- Get yourself a good temperature-controlled soldering iron (or soldering station) right from the beginning. Specially if you are using lead-free solder, which I hope you are.
- Do not underestimate soldering fumes. That can give you even asthma.
- A soldering iron gets very hot. Never put it on the floor or somebody will step on it at some point. Pain ensued.
  - Get yourself a holder where you can put the iron inside, not just leaning over it.
- When soldering pins to a small board, insert the pin strip into a breadboard and use another pin strip to level the module you are about to solder. That will give you straight pins. See picture above.
- Soldering iron tips are very important and need maintenance.
Useful tools
- A good wire cutter. e.g. PLATO 170.
- A metal helping hand tool with a magnifier.
- A desoldering pump.
- Thin straight pliers.
- A pair of ceramic tweezers.
Useless tools
- Every-possible-shape tweezers kit.
  - All you need is a good straight ceramic one.
- Wire strippers.
  - Just cut the insulation with sharp scissors and pull it out with your fingers.
    - Bonus tip: If it is a multicore wire, rotate the insulation as you pull it out to reduce fraying.
Boards
- A Raspberry Pi is one of the best things you can get. Any of them.
- STM32F103 boards a.k.a. “blue pill“ are incredibly cheap and popular. They are enough for many tasks and you can also use them with Arduino if you are into that. Bad clones also exist so beware.
- Alternatively, STM32F411 boards a.k.a. “USB-C pill“ are only slightly more expensive but the build quality and capabilities are much better.
- Otherwise, STM32 nucleo and especially discovery boards are great.
- If you are into Wi-Fi, ESP8266 boards are very cheap. ESP32 boards are more capable and also support Bluetooth. However, currently the Rust support is not as good as on other architectures.
- If you are into Bluetooth, the NRF52 and also NRF51 family of chips are very nice.
- Get yourself an STLink V2 for flashing and debugging (may be included in your board).
  - You can use cool stuff with it like probe-rs.
Breadboarding
- Usual jumper cables are ok but quite rigid. You can buy colored flexible silicone wire and jumper pins and housings and make your own jumper cables, which are much more pleasant to work with. About 24 AWG wire works well. See picture above.
  - Bonus tip: make some of them slightly longer, about 30cm.
- 30AWG “wire wrapping wire” is too thin and fragile for most uses.
- 22AWG silicon wire is the thickest that fits into a jumper connector housing.
- Buy several breadboards. Otherwise you will spend a lot of time just rewiring.
  - Bonus tip: They can be joined together.
- Use always the same color for the clock and data signal wires, respectively.
- Get yourself an “U-shaped” breadboard jumper wire kit. They are easier to follow than long cables.
  - Bonus tip: Don’t be afraid of cutting the long ones to make several shorter ones. They are more useful and reduce clutter.
- With the two lines on the top and bottom of a breadboard you can transport power everywhere easily.
  - Bonus tip: You can use one of these power rails for I2C’s SDA/SCL.
SSD1306 OLED displays are very useful and cheap. You can throw then into any project.
Get yourself an USB <-> USART adapter. You can use it to transmit sensor data easily into your computer and communicate with many sensors and devices.
- Alternatively, you can use a Bluetooth <-> USART adapter. e.g. HC-05.
Pay attention to the voltage range of things.
- Get yourself a bi-directional 5V <-> 3.3V logic level shifter.
Beware of static electricity. It will burn your chips.
Adafruit and Sparkfun have a big catalog of cool stuff, including detailed guides.
You can buy lots of cool stuff very cheap at AliExpress (also eBay).
- However, it has its limits. Especially for quality stuff (tools, boards, solder tin) better go to your local electronics store. Also, they need more support and you can even meet people with similar interests.
  - Remember: Good tools pay off and last longer.
- Buy lithium batteries only at your local electronics store or reputable retailer. They contain dangerous chemicals and can explode.
- Buy solder tin only at your local electronics store or reputable retailer. You do not know what is inside otherwise.
If you are into robots, you can get yourself a simple robot kit so that the mechanics (motors, gearboxes, wheels) are mostly solved for you. Later you can reuse the components to build other robots.
- Alternatively, you can pull children toys apart. However, these are not as easy to adapt to do something else.
If you must use surface-mounted chips, SOP to DIP no-soldering adapters are great for the first prototypes and are also breadboard-compatible. Furthermore, it will save you from burning the chips during soldering trying to get rid of solder bridges.
Resistor, capacitor, diode and transistor kits are great if you are into electronics.
A button kit and LED kit can be a lot of fun.
A cheap logic analyzer can help you a lot when something does not react or acts weird. You can use it together with PulseView.
Oscilloscopes are very expensive. You can build a very basic one yourself using your computer. Search for “DIY oscilloscope”.
You can use prototype boards (a.k.a. protoboards) instead of making a real PCB.

Alright that’s about it.

Final remarks

Build cool stuff just for fun. Do not trust your wellbeing or that of your family to anything you build yourself.
- Validation/QA processes exist for a very good reason and that is one of the things that makes stuff more expensive.
In case you missed it: Lithium batteries can explode!

Be safe and have fun!