Vastly Improved Servo Control, Now Without Motor Surgery

March 21, 2024 by Donald Papp 13 Comments

Hobby servos are great, but they’re in many ways not ideal for robotic applications. The good news is that [Adam] brings the latest version of his ServoProject, providing off-the-shelf servos with industrial-type motion control to allow for much, much tighter motion tracking than one would otherwise be limited to.

Modifying a servo no longer requires opening the DC motor within.

The PID control system in a typical hobby servo is very good at two things: moving to a new position quickly, and holding that position. This system is not very good at smooth motion, which is desirable in robotics along with more precise motion tracking.

[Adam] has been working on replacing the PID control with a more capable cascade-based control scheme, which can even compensate for gearbox backlash by virtue of monitoring the output shaft and motor position separately. What’s really new in this latest version is that there is no longer any need to perform surgery on the DC motor when retrofitting a servo; the necessary sensing is now done externally. Check out the build instructions for details.

The video (embedded just below) briefly shows how a modified servo can perform compared to a stock one, and gives a good look at the modifications involved. There’s still careful assembly needed, but unlike the previous version there is no longer any need to actually open up and modify the DC motor, which is a great step forward.

Continue reading “Vastly Improved Servo Control, Now Without Motor Surgery” →

Cute CO2 Gauge Tells You When To Crack A Window

March 19, 2024 by Kristina Panos 25 Comments

[Cyrill] has a good home automation scheme going: there are a number of physical switches set around the place that control the essential functions. The only problem is that in the winter time, this results in a great deal of phone checking as [Cyrill] tries to monitor the CO₂ level. Tired of all this screen time, [Cyrill] set about to create an incredibly cute (and useful) Co₂ monitor that plainly shows the current level and how bad it is, relatively speaking.

A large servo and an ESP32-S2 make up the guts of an analog CO2 sensor.

Behind that adorable face is a DS3225 servo being driven by a Wemos S2 mini, both of which [Cyrill] happened to have handy. Although the 25 Kg servo may be complete overkill for the situation, [Cyrill] reports that it is quieter than your average AliExpress alternatives, which makes it well worth it in our book. Then it was on to Inkscape to make the gauge itself. [Cyrill] says they’re an Inkscape noob, but that face could have fooled us.

Finally, it was time to integrate it into Home Assistant to get readings from the CO₂ sensors. This was easier said than done, but [Cyrill] does a nice job of explaining how to get the ESP32-S2 up and working.

If you’re out there monitoring CO levels in your home, beware of fake sensors that cropped up during the height of the pandemic and are likely still at large.

Swapping Nunchucks For A Steering Wheel

January 30, 2024 by Bryan Cockfield 4 Comments

Rather than chasing pure performance and high quality graphics like other gaming companies, Nintendo has made a name for themselves over the last few decades by favoring not only artistic design and gameplay, but the physical design of the game systems. Of course the hybrid handheld Switch console is among these, but it also includes things like the novel design of the Nintendo 64 controller and, of course, the Wii nunchuck controllers. They’re not always met with resounding approval, though. Some of us tend to prefer more traditional gamepad design, and will go to extreme lengths to get it like this D-pad for playing Mario Kart Wii.

Rather than simply building a compatible controller for the Wii, or even using a GameCube controller, this controller setup takes a more roundabout approach. A Wiimote is placed in a holster built from Lego, and the game is set up to recognize it as if it were being used in its steering wheel mode. The Lego holster has a servo attached which can tilt the Wiimote from side to side, mimicking a player holding it to play the game, with another set of servos set up to press the various buttons. To control the controller, a homebrew D-pad built on perfboard with an Arduino at its core is used to send commands to the servos, allowing for a more standard controller layout to be used for the classic kart racing game than the steering wheel Wiimote allows.

While it’s quite obvious that there are simpler, easier solutions that avoid the sometimes awkward nature of using Wiimotes, we certainly appreciate the Rube Goldberg-like approach to setting up your gaming experience exactly the way you like. Whether that’s setting up an antique CRT effect for the authentic retro gaming experience or building a complete racing simulator from scratch, the gaming experience is ripe for personalization and unique builds like this one.

Continue reading “Swapping Nunchucks For A Steering Wheel” →

Robotic Rose Of Enchantment Drops Petals On Command

December 19, 2023 by Kristina Panos 2 Comments

In Disney’s 1991 film Beauty and the Beast, an enchantress curses the young (10 or 11-year-old) prince to beast-hood for spurning her based solely on her appearance. She gives him a special rose that she says will bloom until his 21st birthday, at which time he’ll be turned back into a prince, provided that he learned to love by then. If not, he’ll be a beast for eternity. As the years go by, the rose drops the occasional petal and begins to wilt under the bell jar where he keeps it.

[Gord Payne] was tasked with building such a rose of enchantment for a high school production and knocked it out of the park. With no budget provided, [Gord] used what he had lying about the house, like nylon trimmer line. In fact, that’s probably the most important part of this build. A piece of trimmer line runs up through the stem made of tubing and out the silk rose head, which connects with a custom 3-D printed part.

Each loose petal hangs from the tubing using a short length of wire. Down at the base, the trimmer line is attached to a servo horn, which is connected to an Adafruit Circuit Playground. When the button is pressed on the remote, the servo retracts the trimmer line a little bit, dropping a petal. Be sure to check out the demo after the break.

Dropping petals is an interesting problem to solve. Most of the flower hacks we see around here involve blooming, which presents its own set of troubles.

Continue reading “Robotic Rose Of Enchantment Drops Petals On Command” →

Making A Kit-Kat Clock Even Creepier

December 19, 2023 by Kristina Panos 10 Comments

If there’s anything as American as baseball and apple pie, it’s gotta be the Kit-Kat clock in the kitchen. For the unfamiliar, the Kit-Kat clock is special in that its pendulum tail and eyes move back and forth with each passing second. They’re equal parts cute and creepy.

But not this particular Kit-Kat, not once [Becky Stern] got a hold of it. The cute/creepy scales have been tipped, because the eyes of this Kat follow you around the room. “You” in this case is fellow maker [Xyla Foxlin], whom [Becky] drew in the Maker Secret Santa pool. See, [Xyla] loves cats, but is deathly allergic to them. So really, what better gift is there?

In order to make this happen, [Becky] started by disconnecting the long lever that link the eyes and the tail, which move together, and connected a servo horn to the eyes. [Becky] drilled out the nose in order to fit the camera, which is connected to a Seeed Grove AI Vision board with a Xiao RP2040 piggybacked on top.

While soldering on the servo wires, [Becky] accidentally detached a tiny capacitor from the AI Vision board, but it turns out that it wasn’t critical. Although she only had to write one line of code to get it to work, it ended up working too well, with the eyes darting around really quickly. By making the servo move in timed increments to the new positions, it’s now much more creepy. Be sure to check out the build video after the break.

You know we can’t resist a clock build around here, especially when those clocks are binary.

Continue reading “Making A Kit-Kat Clock Even Creepier” →

Single-piece Tank Chassis Goes Robotic

November 27, 2023 by Donald Papp 8 Comments

[EXTREME3DPRINT] has a new version of their print-in-place tank chassis: the PiPBOT now accepts drop-in motors (in the form of 360° rotation servos), RC receiver, and battery pack to make a functional RC tank platform in no time flat. The design is entirely 3D printed with no supports needed.

This new version is a paid 3D model (and it includes STEP files, thankfully) but the original proof-of-concept print-in-place tank chassis is free and remains a highly clever piece of design that really shows off what is possible when one plays to a 3D printer’s strengths.

A better look at the design’s details can be found on the designer’s website, and a short video demonstrating assembly and operation is embedded below. We particularly like the attachment points on the top of the PiPBOT, which allows for securely mounting all kinds of customized payloads.

Interested in this style of printable RC platform, but want something a little more accessible? If race cars are more your thing, we’d like to also mention the Gamma 2.0 by [Under Engineered]. It’s a print-in-place RC car that needs minimal parts to get rolling and would make an excellent afternoon project.

Continue reading “Single-piece Tank Chassis Goes Robotic” →

Robot Sunflower Follows The Sun

November 3, 2023 by Al Williams 15 Comments

Real flowers do it, and even the Beatles did it. [Robo Hub] now has a plastic sunflower that tracks the sun using, of course, an Arduino. It may not qualify as a real robot, but it does mimic a real sunflower. The electronics aren’t earth-shattering, of course. An Arduino, a light sensor, and a servo motor are all you really need. But we enjoyed the whimsy and the artistic sensibility. This would be a great school project, for example. Interesting enough to get kids interested but not so hard as to be undoable. You can see a video of the ersatz flower below.

There are actually a pair of light sensors, as you might expect. That way you can determine which sensor is getting the most light. Obviously, these can’t be on-off sensors. They are, in fact, light-dependent resistors, so you get a nice analog reading.

Of course, you might not need an Arduino for this. A 555 driving a servo and a handful of discrete components could measure a bridge with the photoresistors and get the same effect. On the other hand, a microcontroller these days is inexpensive and versatile, so why not?

Usually, people tracking the sun are trying to get more energy. That doesn’t have to be any more complicated, though.

Continue reading “Robot Sunflower Follows The Sun” →