Robots Hacks

2450 Articles

Print-in-Place Gripper Does It With A Single Motor

February 2, 2026 by 16 Comments

[XYZAiden]’s concept for a flexible robotic gripper might be a few years old, but if anything it’s even more accessible now than when he first prototyped it. It uses only a single motor and requires no complex mechanical assembly, and nowadays 3D printing with flexible filament has only gotten easier and more reliable.

The four-armed gripper you see here prints as a single piece, and is cable-driven with a single metal-geared servo powering the assembly. Each arm has a nylon string threaded through it so when the servo turns, it pulls each string which in turn makes each arm curl inward, closing the grip. Because of the way the gripper is made, releasing only requires relaxing the cables; an arm’s natural state is to fall open.

The main downside is that the servo and cables are working at a mechanical disadvantage, so the grip won’t be particularly strong. But for lightweight, irregular objects, this could be a feature rather than a bug.

The biggest advantage is that it’s extremely low-cost, and simple to both build and use. If one has access to a 3D printer and can make a servo rotate, raiding a junk bin could probably yield everything else.

DIY robotic gripper designs come in all sorts of variations. For example, this “jamming” bean-bag style gripper does an amazing, high-strength job of latching onto irregular objects without squashing them in the process. And here’s one built around grippy measuring tape, capable of surprising dexterity.

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Light Following Robot Does It The Analog Way

January 28, 2026 by 12 Comments

If you wanted to build a robot that chased light, you might start thinking about Raspberry Pis, cameras, and off-the-shelf computer vision systems. However, it needn’t be so complex. [Ed] of [Death and the Penguin] demonstrates this ably with a simple robot that finds the light the old-fashioned way.

The build is not dissimilar from many line-following and line chasing robots that graced the pages of electronics magazines 50 years ago or more. The basic circuit relies on a pair of light-dependent resistors (LDR), which are wrapped in cardboard tubes to effectively make their response highly directional. An op-amp is used to compare the resistance of each LDR. It then crudely steers the robot towards the brighter light between turning one motor  hard on or the other, operating in a skid-steer style arrangement.

[Ed] then proceeded to improve the design further with the addition of a 555 timer IC. It’s set up to enable PWM-like control, allowing one motor to run at a lower speed than the other depending on the ratio between the light sensors. This provides much smoother steering than the hard-on, hard-off control of the simpler circuit. [Ed] notes that this is about the point where he would typically reach for a microcontroller if he hoped to add any additional sophistication.

In an era where microcontrollers seem to be the solution to everything, it’s nice to remember that sometimes you can complete a project without using a processor or any code at all. Video after the break.

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Electric Lawnmower Gets RC Controls

January 27, 2026 by 21 Comments

Decades ago, shows like Star Trek, The Jetsons, and Lost in Space promised us a future full of helpful computers and robot assistants. Unfortunately, we haven’t quite gotten our general-purpose helper to do all of our tasks with a simple voice command yet. But if some sweat equity is applied, we can get machines to do specific tasks for us under some situations. [Max Maker] built this remote-controlled lawnmower which at least minimizes the physical labor he needs to do to cut his grass.

The first step in the project was to remove the human interface parts of the push mower and start working on a frame for the various control mechanisms. This includes adding an actuator to raise and lower the mower deck on the fly. Driving the new rear wheels are two wheelchair motors, which allow it to use differential steering, with a set of casters up front for maximum maneuverability. An Arduino Mega sits in a custom enclosure to control everything and receive the RC signals, alongside the mower’s batteries and the motor controllers for the drive wheels.

After some issues with programming, [Max] has an effective remote controlled mower that he can use to mulch leaves or cut grass without getting out of his chair. It would also make an excellent platform if he decides to fully automate it in the future, which is a project that has been done fairly effectively in the past even at much larger scales.

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Building A Little Quadruped Robot

January 24, 2026 by 7 Comments

Robots don’t have to be large and imposing to be impressive. As this tiny quadruped from [Dorian Todd] demonstrates, some simple electronics and a few servos can create something altogether charming on their own.

This little fellow is named Sesame. A quadruped robot, it’s built out of 3D-printed components. Each leg features a pair of MG90S hobby servos, one of which rotates the leg around the vertical axis, while the other moves the foot. The ESP32 microcontroller controls all eight servos, enabling remote control of Sesame via its built-in wireless connectivity. Sesame also gets a 128×64 OLED display, which it uses to display a range of emotions.

Mechanically, the Sesame design isn’t particularly sophisticated. Where it shines is that even with such a limited range of motion, between its four legs and its little screen, this robot can display a great deal of emotion. [Dorian] shows this off in the project video, in which Sesame scampers around a desktop with all the joy and verve of a new puppy. It’s also very cheap; [Dorian] estimates you can build your own Sesame for about $60. Files are on GitHub for the curious.

If you prefer your quadrupeds built for performance over charm, you might consider an alternative build. Video after the break.

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Robot Sees Light With No CPU

January 19, 2026 by 10 Comments

If you ever built a line following robot, you’ll be nostalgic about [Jeremy’s] light-seeking robot. It is a very simple build since there is no CPU and, therefore, also no software.

The trick, of course, is a pair of photo-sensitive resistors. A pair of motors turns the robot until one of the sensors detects light, then moves it forward.

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The Best Robot Mop System: Flat, Spinning, Or Roller?

January 17, 2026 by 6 Comments

When it comes to designing a mopping robot, there are a number of approaches you can pick from, including just having the movement of the robot push the soggy mop over the floor, having spinning pads, or even a big spinning roller. But what difference does it make? Recently the [Vacuum Wars] channel ran a comparison to find out the answer.

The two spinning pad design is interesting, because it allows for the bot to move closer to objects or walls, and the base station doesn’t need the active scrubber that the simple static pad requires. The weakness of both types of flat mop design is that they are quickly saturated with dirt and moisture, after which they’ll happily smear it over the floor.

The spinning roller is the most complex, with the robot having its own onboard water tank, and a way to extract the dirty water from the mop and store it for disposal in the base station. Theoretically this would be the clear winner, with basically all of them having features like avoiding carpet.

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Building A Carousel Autosampler

January 15, 2026 by 3 Comments

A common task in a laboratory setting is that of sampling, where a bit of e.g. liquid has to be sampled from a series of containers. Doing this by hand is possible, but tedious, ergo an autosampler can save a lot of time and tedium. Being not incredibly complex devices that have a lot in common with e.g. FDM 3D printers and CNC machines, it makes perfect sense to build one yourself, as [Markus Bindhammer] of Marb’s Lab on YouTube has done.

The specific design that [Markus] went for uses a sample carousel that can hold up to 30 bottles of 20 mL each. An ATmega-based board forms the brain of the machine, which can operate either independently or be controlled via I2C or serial. The axes and carousel are controlled by three stepper motors, each of which is driven by a TB6600 microstep driver.

Why this design is a time saver should be apparent, as you can load the carousel with bottles and have the autosampler handle the work over the course of however long the entire process takes instead of tying up a human. Initially the autosampler will be used for the synthesis of cadmium-selenium quantum dots, before it will be put to work for an HPLC/spectrometer project.

Although [Markus] intends this to be an open hardware and software project, it will take a bit longer to get all the files and documentation organized. Until then we will have to keep manually sampling, or use the video as the construction tutorial.

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