Ask HN: How do I get into robotics?

Take a look at the already assembled robot arms available on eBay, they vary a lot in price but even the cheapest ones could be used to explore the software side of controlling a robot arm. The main thing you'll learn from programming a cheap robot is what its limitations are (lack of fine control or repeatability, lack of strength, quick to wear out, difficulties in handling overload situations). Then you'll know what you want to study next and have some idea of terminology (always important to learn the special words technologists use in their field). So, for example, you'll learn that servos work, but are slow and not very powerful or repeatable. Stepper motors may be an improvement but have limited resolution due to moving in steps. Moving fast requires a lot more power. Adding sensors to measure the actual rotation at joints (or distance for linear actuators) can improve repeatability. If you want to learn the electronics side of robotics start building simple circuits using a solderless breadboard, you can get parts at JameCo, DigiKey or Mouser (do a web search). There are lots of web sites with projects you can build. The ones that explain the theory as well as show how to build the circuit will teach you the most. Electronics has a lot of detail in it, there are thousands of types of components, many ways of interfacing things, lots of limitations in power and frequency, it is somewhat like software programming in those respects. Jumping in and building things alongside more formal learning paths is a good way to get started. Stick with low voltage, low current circuits to start with until you learn how to safely deal with higher voltages and currents (which can be deadly). Learning mechanics it is probably simpler to start with theory rather than building things. There are not a lot of kits or examples for building mechanical things that I know of (Lego? Erector sets?) that also teach you theory (stress, deformation, mass versus speed, calculating maximum load at the end of an arm, trajectory computation, etc.) The ROS software library and some exposure to machine learning could be helpful as well. Higher level software topics like SLAM (simultaneous location and mapping) and path planning and machine vision you can look at to start learning and study in more detail later. Sensors are an entire field in themselves (mechanical, optical, chemical, RF, pressure, humidity, cameras, air pressure, color, distance,...) A robot is like a person, complicated and built of systems on top of systems and you need to learn at least something about all the levels to be proficient in designing a complete system that works the way you want it to. It's a lot to learn, though you can also specialize in those parts you find more interesting. Some people do nothing but path planning or machine vision.

Check out James Bruton's excelent youtube channel https://www.youtube.com/c/jamesbruton/videos

The general process he uses in his projects is worth emulating, as well as many of his design choices. He also provides 3d print files and code.

As far as a specific project that would be a good entry point, I reccommend making some variety of inverted pendulum which is actively balanced by a microcontroller. Every skill needed to achieve this is fundamental to succeeding and having fun in robotics.

Commenting to revisit later! Thanks for these resources.