Ask HN: How to get started with robotics as a hobbyist?

Do a real project with goals and expectations. Learn exactly what you need to get the task done. Do not buy a ROS book. Do not spend huge amounts of time exploring the ecosystem. Just focus on making it “do the thing”. The experience will come when the goals are met. Source: I built the entire initial software stack for the FarmBot project (minus the gcode handling firmware, thanks Tim) and had zero hardware experience when I started. I can compile embedded Linux kernels from scratch and whatnot now.

I was very interested in athletic robots, so I left my job in software to build a quadruped and make it backflip [1]. I made the hardware at home (the design was open-source [2]) and wrote the framework to generate jumps, flips, etc. I started with basically zero robotics knowledge, so it was a lot of work, but it was incredibly fulfilling and super fun. I personally learn best by building things.

I'd say start playing with 3D printing and motors to make mechanisms that move (pendulums, simple walkers, ...). +1 to tinkering with the 3D printer itself (that someone mentioned) as you can learn a lot about how the machine works and figure out ways to improve it.

You've mentioned the physical aspect, but simulation could also be a good starting point. You can now very easily train RL agents in sim to say, walk, and transfer to real hardware afterwards.

Finally, if you like flying stuff, there's drones you can buy that are controlled programmatically (e.g. Crazyflie). I haven't played a lot with these, but I've seen them used to teach control and they seem like a nice, inexpensive platform to experiment with.

[1]: https://github.com/rkourdis/trajopt?tab=readme-ov-file#backf...

[2]: https://open-dynamic-robot-initiative.github.io

Get an arduino kit and learn a little electronics. The kit likely comes with a brushed motor and a servo. Learn how motors works and how to write code to make motors spin. Then get a stepper motor and an arduino-compatible motor shield or CNC shield and spend some time getting multiple motors to move. Once you understand those basics, you can hook motors together in a rigid frame and you have a robot (2 motors with wheels is mobile, 3 or 4 motors with links is an arm). The kit will also come with some simple sensors which you can use to do things like measure light and distance, which you can use to start playing with feedback control (look up Braitenberg vehicles for a project idea).

Seconding all the people who said avoid ROS - it's not worth the effort for hobby-level stuff. It's barely worth the effort for "professional" robotics.

Also don't worry about physics too much - build your physical intuition by playing with working systems of increasing complexity.

As someone who has been learning robotics as a hobby for a decade, my advice is: forget all the buzzwords and what the industry is using and start small instead.

I started robotics at a young age and began with small builds with LEGO motors and sensors, getting a feel of how each one works and how to interact with them with code. Then I got to much more advanced programs with LEGO Mindstorms EV3, learned about things like PID controllers practically and even started taking part in some competitions. Next, I went to writing actual code (as opposed to block-based programming) on microcontrollers like the micro:bit (and a few years later the Raspberry Pi Pico). I deepened my knowledge of how electronics work and learned how circuits work. I eventually got into a team with a few friends and we built a human-size robot combining 3D printing, a bunch of circuitry, ROS, 2 SBCs, Arduinos, a LIDAR and OpenCV for face/object recognition. This took years of learning step-by-step to achieve.

This is obviously not the path you'd take, robotics was what brought me into programming and you're probably going for the opposite.

You're not going to build a perfect robot or electronic device from the start and you shouldn't try to either. Get a microcontroller that's newcomer-friendly and play around with it. A micro:bit mostly emphasizes on the end result, with a built-in display and sensors and many plug-and-play modules to get you going. A Raspberry Pi Pico is much more flexible, but also requires you to learn about wiring and doing more things yourself. If you prefer coding in C, go for an Arduino. An ESP32 is also a good choice. It's a good idea to get a 3D printer and learn CAD in parallel, as it's a great way for a hobbyist to create actual tools that are more than a bunch of wires.

Once you get enough experience and confidence in your skills, you'll want to get into more advanced projects. Use your knowledge to plan them out, research and learn the technologies you're going to use (you can't learn everything beforehand and each piece of hardware is something different) and enjoy the journey from prototype to finished project.

And by the way (you didn't mention it but other comments here are so I'll give you an opinion on that), ROS is nearly always overkill for hobbyist robotics projects :D

I hope that helps you start your journey!

I would always prefer to start with a kit that will work right a way end to end, than focus on each problem subset to do deep dive. so101 is a highly available 3d printed and servo motor based robotic arm. That can be combined with nvidia orin like sbc as a good starting point.

Worth to check also https://www.printables.com/ for small cute 3d printed robot projects that you can build using stm32 or esp32 boards. You shall check Adafruit/Sparkfun like websites for dev boards, they even support micro python for quick prototypes.

https://www.hackster.io/shahizat/running-lerobot-so-101-arm-...

The simplest project that covers the basics of motors and controls is a self-balancing robot. 2 Motors, an h-bridge, a battery, an IMU, and a microcontroller.

A step above that I would say some kind of wheeled robot with more complex motors that have encoders, and ROS if you want to mess around with autonomy. If you have the budget for it, a stereo camera or $400 time-of-flight RGBD camera can get you pretty much full autonomy (if you configure all the ros nodes for it).

If you are into robot arms, LeRobot has a desktop robot arm kit that uses neural networks to control a robot arm with a camera for seeing the world.

If you want to learn the theory, I really like Probabilistic Robotics by Sebastian Thrun, and Modern Robotics by Lynch and Park. Those cover pretty much all of the foundational concepts for autonomous robots.

The most fun thing I think currently are drones. I have been designing and building a fixed-wing drone with autonomy and FPV capabilities. Started from zero information and just learned as I went. Plus flying drones is more fun than driving robots IMO.

It really depends on what you want to do. Start with a list of projects you want to build. Are they really robotics or just home automation? If you have no experience with embedded programming, I'd start with home automation or other simple hardware stuff first. Learn how to read sensors and operate lights or motors before you get any deeper into the craft.

There are three reasons why "real" robotics is harder. First, to navigate unconstrained environments by means other than wheels, you need to learn a fair amount of kinematics and control theory. Second, your robot will need to build a map of the operating environment, which often requires complex sensing (lidars, cameras) and a lot of compute power. Even something as basic as a Roomba is no small feat, and these things get stuck a lot. Third, it's just hard to come up with practical applications for simple robots outside of industrial production lines.

Once you have that figured out, decide how much you want to learn. Do you want to do it the hard way, which would mean moving more slowly and working your way up from first principles and probably 3D printing or machining your own parts... or do you want to get results as soon as possible, in which case, you probably buy a Linux single-board computer and put it on top of an existing robot kit? The trade-off with the first approach is that it will take you months or years to get where you want to be. The downside of the second is that you're limited to premade kits and software components, and once you exhaust the possibilities there, you kinda hit a wall.

- Learn basic electronics.

- Learn about micro controllers and embedded programming.

- Learn about motors.

- Learn about gears, pulleys, torque - some physics things - enough to think about how you could potentially build something.

- Build something small. Maybe a robot sunflower that follows the sun with a built in solar panel that keeps its battery charged... I dunno, I just came up with that. Or an automatic blinds opener / closer for your blinds / home curtains.

- Learn, build, rinse, repeat..

First: Get a 3d printer, if you don't have one. No quicker way to turn ideas into physical objects for prototyping and iteration.

Second: Pick a project with modest but not trivial goal. Something that exists within the state of the art on at least most axes. e.g. make a quadcopter, make a 3d printer, or make an automated cat food dispenser. The project can be special on an axis, e.g. I want the break the drone speed record, or make the best battle bot for a weight class - but stacking too many novelties into a project compounds the difficulty.

Three: Break down the project into manageable sub tasks, starting simple then working towards integration. E.g. step 1, make a drone motor spin. Step 2, make a drone motor spin at exactly 2503rpm. Step 3, design a housing to fit four drone motors/control board/battery, etc. It's perfectly natural/common/fun to play this by ear, many projects will go back and forth between biting off more than you can chew and isolating model systems for testing.

Four: Integrate the subsystems, test, debug and most importantly repeat.

[0] The Bambu a1 mini is a perfectly competent entry-level product. And Fusion360 is a solid CAD for design side.

The book "Robot Builder's Bonanza" is a nice introduction and gets you started on the hardware side.

If it's a hobby, I'd stay away from ROS, as it's a pain in the cloaca to set up and use. Just build stuff, and run it with one script or ten if you need to. Build stuff. Debug. When you need ROS, you'll know it.

>How did you started on your journey with robotics?

Building RC cars, RC quads, 3D FDM printers, and LinuxCNC/EMC 3-axis mill retrofits.

>what's handy to learn in the first place?

Depends on your learning goals, and desired platform budget.

1. Some sort of basic EE topics in a school, or Ham technician license

2. Basic project book on Arduino: blink LED, move RC servo, spin motor, and make speaker beeps etc.

3. Build cheap Arduino turtle bot kit, racing drone, and or a RC car kit

4. Build a 3D printer kit like LDOmotors voron, or join a local space to get CAD/printing skills

5. ROS tutorial to connect Arduino turtle bot kit to simulated environment

6. Courses on Forward Kinematics, Inverse Kinematics, OpenCV Machine Vision, POMDP, NN, Kalman filter, and PID motor control.

7. Build a small 7-axis robot arm path planner in ROS simulator

8. Build a Autonomous mobile Robot with your SLAM of choice, and bolt arm to turtle/tracked platform

9. Gain the wisdom of the tribe around guidance and navigation problems

10. Build some sort of walker: Heaxapod (easy), quad (challenging), and biped (hard)

11. Remember to test everything outside in sun, wind, and rain. There is a lot of expensive garbage products that only sort-of work in ideal circumstances.

Again, the path may be greatly simplified if your goal is only to use robotic platforms... rather than build something expensive. For example, the Yarbo core platform looks like a fun mid-sized project to retrofit, and defunct units are under $1.5k off auction sites.

Have fun =3

I highly recommend starting with the very affordable and well documented Lerobot SO101 arms. You can 3d print or buy parts and actuators, camera. Lots of tutorials and training policies, data collection and simulations. https://huggingface.co/docs/lerobot/en/so101

With my kids we did Le Robot from hugging face over the Christmas break, it was a fun project to put together the kit and get the follower arm to follow the leader. You can also train ML models with it etc https://huggingface.co/docs/lerobot/en/so101

Buy some serial servo motors and program them.

Learn about how to battery-power projects, starting with a microcontroller board and your servo.

Learn power distribution circuitry - wire gauges for given loads, etc.

Learn some useful control/animation bits, e.g. play around with an IK library.

This is more or less what led to my own first robots (a simple walker, then a more ambitious hexapod, etc.)

My college robotics course used Lego Mindstorms (back before the kit was discontinued) because it offered quite a lot for the price.

Our robots needed only to complete a simple task of finding the "reactor" (array of IR LEDs) on a 1x1m fenced board, but Lego more than delivered on the hardware front, because we had an IR sensor, an ultrasound proximity sensor and few other ones that we didn't even use.

Really helped to bridge the gap between theory and practice because it's one thing to program a servo motor and a completely different one to see your dead reckoning algorithm be off by a mile. Also sensors do a lof of things you don't expect.

Its succesor is named Lego Spike Prime, but I never used it, so can't comment.

Buy an Arduino and some hobby servos and tinker with them.

But ideally you would have a goal in mind. what do you want your robot to do? (pass butter?) Once you have a goal then you will be able to focus on just what you need to learn to achieve that goal.

Like many have said, start with Arduino-like boards + servos. You can get servo driver boards that let you plug in multiple servos to your Arduino without power problems. Get those from Adafruit. Then you can graduate to the "bus" style servos like Feetech if you want to load up on servos.

If you want to learn to make PCBs, this tutorial shows you how to design them in open source software and then get them made cheaply (highly recommend): https://www.youtube.com/watch?v=PlDOnSHkX2c

Get a CAD program like Onshape (I love Onshape). Learn how to use it to design 3d printed components. Get a 3d printer. Maybe Bambu Lab. Now you should be able to make nice form factors for your robots. If you want to graduate from 3d printing to Aluminum, then you can send your designs to a place like PCBWay or JLCPCB and get the aluminum parts reasonably cheap.

At some point when you want to make a more "real" robot, read this guy's thesis and try to understand almost all of it: A low cost modular actuator for dynamic robots https://dspace.mit.edu/handle/1721.1/118671 It goes over so many things that are useful, like types of actuators, how they're designed, controlled, etc. I wish I had read that earlier. Then if you want to make something like that, I highly highly recommend MJBots. https://mjbots.com/

Make something amazing!!!

I recently got started and as others have said, it helps to have some idea of what you want to do, since 'robotics' is such a wide field. In my case I was curious if I can get LLMs to drive a robot, so I bought a quality, mostly-assembled chassis (https://www.waveshare.com/ugv-beast.htm) that let me focus more on software and sensors. If you want more low-level stuff, you can make your own chassis (motors, 3d printed parts, arduino/esp32 programming), you can make your own attachments to chassis like the one I have, etc. On the software side, you can focus on navigation/mapping or operating actuators on a stationary base, you can run small specific models (segmentation/etc) paired with classical algorithms, you can run VLAs (LLMs that output motor actions instead of words). There's really quite a bit to do.

I wrote a bit about how I got Gemini to drive my rover here, it might give you some ideas of what the software side looks like: https://martin.drashkov.com/2026/02/letting-gemini-drive-my-...

What is exciting enough for you that you'll be able to sustain your interest? There's a lot of learning.

I'm going to maybe diverge from some advice and say try and start with hardware connected to your laptop. That's how I started way back (during the original IBM-PC era and a Data Acquisition Card from IBM). Learn how sensors, motors and actuators work. If you were near me I'd lend you a kit I have sitting around that I got for my kids but I'm sure there are options to hook up some basic I/O (Analog and digital) to your laptop.

I would decouple the embedded aspect from this for now and really many embedded systems are running "real" large computer systems. You can build a lot on your desk and having a "real" computer will take away some of the additional hassle of dealing with various embedded platforms. Once you gain a better understanding of the components you can always move to some embedded setup.

The Art of Electronics is one book I will recommend. I would say though start with a kit and use AI or Google search to get some basic circuits going.

Remember the old adage; "Crawl, Walk, Run". Since you say that you don't have much background in Embedded Systems, you have to start simple, easy and with hand-holding.

Parallax used to have "BoE-Bot Robot Kit" with a manual titled "Robotics with the Boe-Bot" which consisted of detailed walk-throughs of projects i.e. what to wire, what to program and test. Download the manual from here (or anywhere on the web) - https://www.parallax.com/product/boe-bot-robot-kit-serial/ Go through it to see what all is involved. The above used a stamp mcu with basic language programming which you don't want.

Get an Arduino kit copying the above kit. Follow the projects given in the manual above but using C/C++ to program your Arduino based robot. You will find tons of resources on the web to help you with this. This will give you the absolute fundamentals of simple robotics.

Simultaneously you also have to study embedded systems programming, particularly focusing on hardware and how to interface with them. You also have to learn to use a simple USB Oscilloscope/Logic Analyzer/Multimeter as needed. See my previous comment chains here for how to get started - https://news.ycombinator.com/item?id=33628025 and https://news.ycombinator.com/item?id=44244831

At the end of the above exercise, you will have a good idea of how to program embedded systems using C/C++, understand mcus, understand how to interface them to sensors and other hardware, how to debug problems in the circuit etc. You now have the knowledge and skills to move on to bigger, better and more complex projects.

How I started. Once upon a time there was this magical kingdom called Radio Shack. But it's people left the Earth and went to Capacinor - the Unshorted Lands, a place where batteries are always charged and every circuit board has a schematic.

Nowadays there is Pololu, Robotshop, Sparkfun, Adafruit, and Battery Space. Maybe Microcenter, Ebay, and Temu.

How I did it: buy a Gen 2 Teddy Ruxpin from eBay, a bench power supply, a soldering kit, and an Arduino, and start tinkering

Thank you for the inspiring post.

I began as an electronics hobbyist in the 6th grade in 1966, as a computer programming hobbyist in late 80's, but have never had any projects which would fit squarely within "robotics".

Your post sent me on a wonderful, hours long web search beginning at the English Wikipedia "Robotics" article. From there I found William Grey Walter and his interesting "Machina speculatrix" robots.

His book, "The Living Brain, W. W. Norton & Company, New York (1953) ISBN 978-0393001532" is available for borrowing (with login) at the Internet Archive at <https://archive.org/details/livingbrain00walt>.

This will be the beginning of my new robotics hobby.

If you have a child, you should definitely check out FIRST, started by Dean Kamen, who also invented the Segway. For elementary students, FIRST LEGO League uses simple, LEGO-based robotics. In high school, FIRST Robotics has the students building very impressive robots.

i do robots for work (formerly drones, now self driving cars). pick a type of robot that interests you. self driving rovers, industrial manufacturing machines, drones, humanoids, underwater pipe inspecting subs are all robots with very different technologies underlying them. very hard to just “learn robots” you gotta have something in mind that you think is cool that is the direction you wanna go in, otherwise e.g. you learn inverse kinematics and it’s completely unnecessary for delivery drones, or you learn VLMs and it’s completely unnecessary for industrial robots. start with the goal and then peel back the onion. good luck!

I’ve started doing robotics again after decades working in software and systems engineering. For a few years I’ve been building robots with servos and arduinos as the controller. They weren’t very smart, the servos were too slow and too weak.

So I looked at Huggingface Lerobot project. I ordered the servos for the SO-ARM101. Trained it to pick up a ball and throw it. That sucker launched it across the room. I’ve now replaced the gripper with a TPU soft grip. And I’m training it to use a pen and paper.

These newer Dynamixel and Feetech servos are far more capable than the old RC servos I was using for years. They have torque and position sensing.

I run the electronics of an art university. My recommendation is to (1) start with the basics, that probably means getting an Arduino (or simulate one using wokwi) and working through some basic examples and play around and customize them. Then (2) pick an ambitious but realistic project that you can work on in stages. Maybe you build a simple robot that can turn and go forward with wheels on a flat surface for example. You can then expand it with more sensor capabilities as you go.

It is very important that you just do it. There is no way of learning to play the guitar without actually playing the guitar.

I started mentoring an FRC (high school robotics contest, not battle bots, about 110# mostly custom robots playing a 3v3 game) team 2 years ago and it’s really been enjoyable and rewarding to see the students grow in their capabilities and to have a competitive framework, a timeline, budget and time pressure, and then a break from the insanity when the season is over.

Many, many teams need technical mentors and I really look forward to each season. Not 100% if I’ll continue once my kids graduate, but I wouldn’t rule it out.

I'm working on an autonomous rover to deliver homebrew to my neighbors. It's a silly idea, but having that mission has resulted in a wild journey for me. I think it's the key to doing something more interesting than someone else's tutorial.

Here's my build blog: https://crawforc3.github.io/blog/rover

Feel free to reach out if you just want to chat.

For inspiration, check out Ben Katz. He worked on the MIT Cheetah and electrified the Boston Dynamics dog

https://build-its.blogspot.com/2019/12/the-mini-cheetah-robo...

He designs and machines parts, designs SoTA electronics like motor drivers. Applies robot dynamics, material science, control theory

Closed loop control systems! I'd say that's a common requirement of any robot. I wouldn't spend a lot of time on theory though, just look up the concept of PID and implement it. It's easy. No library needed. There are lots of ways for control loops to perform badly and there's all the theory of that but you can also intuit a lot of it by playing around with motors, encoders, and microcontrollers.

The current go-to is the LeRobot SO 101 + the LeRobot lib from HuggingFace.

Not the best professionnal lib (still young and amateur) but really good to start doing imitation learning / reinforcement learning projects.

If you get more skills on this later and look for a job in a high level AI / RL / Robotics startup in Europe don't hesitate to put up a CV link below my msg and we may contact you.

Recently bought a simple robot (hiwonder puppypi). It’s kind of a mess but armed with something like codex / Claude code it took me couple of days to the get int the rhythm of things. Bu the end of the week I was able to add new features understand the basics of ROS2.

I think it’s solid introduction, learning by doing.

BEAM robots are a stupid-simple way to start. A great project if you just want to follow some instructions and learn to solder, learn circuit components, play with low-power solar, etc.

https://smfr.org/robots/

I want to learn robotics too!! I have a feeling that trying to build something helpful for myself, with help from LLMs, could be a good strategy—but I have no idea! Possibly budget-friendly

If you are after it for fun, comments have you covered. If you are after it for work, don't; the community is toxic and full of Dunning-Kruger individuals, gatekept, and there's this weird vouching too. A lot of fraud, either on an individual level by over-marketing themselves to get a job, or at an organizational level where so many demos you see around are mostly not as accurate as they claim, and the last straw is unfortunately a lot of it recently is shifting towards weaponized robotics with all that that means. Also, because all software folks are having a hard time finding jobs, they are flocking into robotics, which has disturbed the balance in supply and demand. It has turned into a competitive field with low wages, and if you complain, there are hundreds willing to take your spot, or you're being told that you work on "cool stuff, so that's your reward!!" In Canada, for example, I have seen "senior robotic engineer" positions with job descriptions enough to build a spaceship that pay 65K Canadian dollars, meanwhile a snowplow operator operating a machine while listening to music makes 110K. So the juice isn't worth the squeeze now, but if you are after fun cool projects, then by all means please do. I would love to see more robotics content here on HN.

These hack packs looked like a fun way to start and play: https://www.crunchlabs.com/products/hack-pack-subscription?p...

Build an army of robots to help you get started with robotics (as a hobbyist).

Start with a simple analog Braitenberg vehicle and learn how to ascribe intelligent behaviour to a purely mechanical system.

Lots of ways to start. None of them are wrong. Just let your passions lead you to something you’d like to explore. Maybe start with a hackable 3D printing kit that will let you build parts for more robots. Hacking the 3D printer can directly teach you a lot about robotics.

https://simplefoc.com/ Is my type of rewarding nerdy topic. You might be more attracted to other control strategies.

Mastering robotics as a DIY thing is usually more about the mechanical (particular linkages and kinematics) as well as electrical (particularly motor control). The programming part of it generally can be lower quality and more hacked together, but still can be an area of deep exploration if that’s your passion.

https://youtu.be/pJj6uGcMco4?si=J0ui8LzYxEBXePZ0 ‘Engineer Bo’ is a small YT channel with a few great videos about stepper motor control. This video is about protecting the motor driver chip from large surges of electricity when the motor tries to wuickly “brake”. There’s a second video where he iterates on this solution.

If you don't find the mechanical and electrical parts something you want to invest enough time in to learn, and want to just dive into the programming side, then you could focus on simulation entirely. In that case, look into MuJoCo or OpenAI Gym (ported and maintained by community as ‘Gymnasium’).

Don’t be afraid to ask LLMs to help you learn. They might lie to you or occasionally send you down a non-optimal path, but they’ll be helpful first exposing you to so many of your current blind spots and helping understand the scope of any endeavor you might be interested in.

If you do decide to really invest in learning the electrical and mechanical sides, it can be worthwhile to truly learn them. This would involve following something like MIT’s open courseware (or similar) for electrical and mechanical engineering. You can get away without formally teaching yourself these, but it would unlock “real” engineering. Multivariate calculus is possibly enough for the mechanical side, but for electrical you’d also want to understand how to utilize differential equations. So in total, somewhere between the equivalent of 2-4 semesters of calculus. Linear algebra can help as well, but plenty of people without these math skills make really cool stuff in robotics.

You wouldn’t necessarily need to do the calculus and differential equations by hand like we did in University - as long as you can set up, manipulate, and solve the problems using computer software (numerically, maybe some symbolic manipulation) that would be enough for the hobby.

For enjoying robotics “as a consumer” (rather than as a do-er) there are some fun YT channels, which could either inspire you or scratch the itch passively just enough to rob you of the initiative to actually do it yourself:

Stuff Made Here

Mike Shake

Allen Pan

Michael Reeves

I did a thing

CodeBullet (towards the pure simulation side. this channel helps me when I’m feeling like a poorly educated useless engineer because it shows me that even the absolute lowest effort, dumbest approaches and worst execution can produce something both fun and rewarding. That can help me get out of ruts sometimes)

AlphaPhoenix (absolutely next-level explainers and demos of fundamental electromagnetic concepts and phenomena. The 3B1B of EM physics.)

Buy a robot kit from Pololu Robotics

LeRobot SO-101

Trying to build a robot is the way to start the robotics hobby. Reading about robots, studying physics etc. are different hobbies and fine in their own right, but not a robotics hobby.

There is no wrong way to do a hobby. Good luck.

Look for three papers on "integrated mental architecture" and personality, psychopathology then drill down to experimental robotics and begin from a standard text and devkit.

If the goal is to find a hobby why are you asking? Usually a hobby is something you find fun.

Go through the ROS tutorials, using a simulated robot at first, then buy a tiny AMR kit and do the same thing IRL. Once you have those basics, you can ask yourself into which direction to go next, the obvious choices being 1) deeper into the research of the new-fashioned (bi-)manual manipulation (arms), or 2) more into business and actually build a real-world application for your mobile robot (which will involve a lot of tinkering with hardware). And +1 on what brudgers said. It's a hobby, so have fun.