Circuit Sculpture Vibration Sensor

January 10, 2021 by Kristina Panos 15 Comments

Here’s your useful and beautiful circuit for the day — [New Pew]’s vibration sensor takes manual control of the flip-flop inside a 555 timer and lights an LED in response. Use it to detect those vibrations you expect, like laundry machines, or those you only suspect, like the kind that might be coming from your engine. This gadget isn’t super-precise, but it will probably get the job done.

The vibration-detecting bit is a tiny ball bearing soldered to the spring from an old pen, which is tied between the trigger and ground pins of the 555. When the chip is powered with a 9 V battery, nearby vibrations will induce wiggle in the spring, causing the ball bearing to contact the brass rod and completing the circuit. When this happens, the internal flip flop’s output goes high, which turns on the LED. Then the flip flop must be reset with a momentary button. Check out the build video after the break.

Want to pick up Earthly vibrations? You can detect earthquakes with a homemade variable capacitor, a 555, and a Raspberry Pi.

Continue reading “Circuit Sculpture Vibration Sensor” →

Lego Heist Bot Steals Keys

January 9, 2021 by Lewin Day 7 Comments

Breaking and entering is a felony offense, and one that risks the interloper receiving serious bodily harm for the trouble. Sending in a robot instead is an attractive alternative. While we doubt any actual intention to use their creation for evil, [Brick Experiment Channel] have nonetheless built a viable heist bot out of Lego.

The robot in question is actually two, that work together to execute their mission. Once lowered in the house, the scissor lift bot drives into position next to a coffee table. It then lifts its companion bot into position by extending its motor-driven linear actuators. The recovery bot then drives out onto the table, snatches a set of keys with its arm, and returns to the lift bot, before exiting the house. It’s all achieved with the use of the SBrick, a third-party Lego accessory which allows remote control of Lego motors over Bluetooth. A wireless camera also helps out with vision for the platform.

Lego really does make it easy to build quick, functional mechanisms without a whole lot of fuss. We’ve seen it employed in all sorts of ways, like this handy film scanner. Video after the break.

Continue reading “Lego Heist Bot Steals Keys” →

FISHBOT Reels Them In So You Don’t Have To

January 8, 2021 by Tom Nardi 9 Comments

Fishing is generally thought of as a relaxing and laid-back activity, but it still requires a certain amount of physical strength and dexterity. This can be a problem for older anglers or those with physical disabilities. To bring back the simple joy of fishing to those who may no longer be able to hold a rod on their own, [Ozz] has been working on the FISHBOT.

The FISHBOT looks like a miniature crane, complete with an electric motor and winch to pull in the line. But there’s a bit more going on here than meets the eye. Anyone who’s tried to land a large fish knows you have to be cautious of snapping the line, so [Ozz] has added a load cell to the system that can tell when its being pulled too tightly. In the future he hopes to make this feature a bit smarter by taking into account additional variables, but for now it should at least keep the more energetic of your quarry from getting away.

[Ozz] is controlling the beefy 400 watt motor with an IBT-2 H-bridge module connected to an Arduino Mega. The electronics can communicate with the user’s smartphone over a HM-10 Bluetooth module, which allows for more advanced features such as gesture controls that utilize the accelerometer in the phone. Long term, it sounds like he hopes to use the microcontroller in conjunction with the load cell to pull off more advanced tricks like weighing the fish and sending the data off to the user’s fishing buddies to show off.

In the past we’ve seen a drone used to get a lure out where the fish are, but catching one and reeling it back in is a very different challenge. It looks like [Ozz] still has some work to do on this project, but so far it seems things are going well. Being able to return a simple pleasure like this to those who thought their fishing days were behind them will surely prove worthy of the effort.

Continue reading “FISHBOT Reels Them In So You Don’t Have To” →

Hands-Free Page Turning

January 7, 2021 by Chris Lott 12 Comments

For people who can’t lift a finger to turn the page on their ebooks, a solution is at hand. Seoul based technology company Visual Camp has adapted their eye tracking algorithms to an ebook reader. (Video, embedded below.) Reportedly this is the first time an ebook reader has been so equipped.

If your eye lingers on the page turn button, it will turn the page. While this particular application seems innocuous, some of the other applications being touted seem a little contrived if not invasive. For example, applying gaze analysis while you are reading a book, they claim to be able to make targeted recommendations for other books.

We’ve discussed eye tracking devices before, but they have utilized hardware. Visual Camp claims their AI-based technology only requires a color camera and can be integrated into existing camera-equipped devices, such an this ebook reader. They also offer a SDK for developers who want to add eye tracking control into their apps. Eye tracking is hard, though, and the devil is in the details. It’d be neat to see what they’re up to.

Continue reading “Hands-Free Page Turning” →

Custom Controller Makes Turbomolecular Pump Suck

January 6, 2021 by Anool Mahidharia 16 Comments

[Mark Aren] purchased a pair of Turbomolecular pumps (TMP) sans controllers, and then built an FPGA based BLDC controller for the Turbomolecular pumps. A TMP is similar to a jet turbine, consisting of several stages of alternating moving turbine blades and stationary stator blades, and having turbine rotation speeds ranging from 10,000 rpm to 90,000 rpm. TMP’s cannot exhaust directly to atmosphere, and must be combined with a backing (or roughing) pump to create a lower grade vacuum first. They find use in lots of applications such as electron microscopy, analytical sciences, semiconductors and lamp manufacturing. With the lamp industry rapidly embracing LEDs, many of the traditional lamp making lines are getting decommissioned, and if you are lucky, you can snag a TMP at a low cost – but it still will not be cheap by any means.

The two BOC-Edwards EXT255H Compound Molecular Pumps (PDF), that [Mark] bought did not have their accompanying EXC100E Turbomolecular Pump Controllers (PDF), and given pandemic related restrictions, he decided to build a controller of his own, using components and modules from his parts bin. The pump and controller user manuals offered only sketchy details about the sensored BLDC motor used in the pump. The low phase-to-phase resistance implied low drive voltage, and [Mark] decided to try running it at 24 V to start with. He already had experience using the Mitsubishi PS21245-E IGBT inverter bridge, and even though it was rated for much higher voltages, he knew that it would work just fine at 24 V too.

After figuring out a state machine for motor commutation that utilized PWM based adjustable current control, he implemented it on a 128 element FPGA board. Considering how expensive the TMP was, he wisely decided to first try out his driver on a smaller “expendable” BLDC motor. This whole process was non-trivial, since his available IGBT module was untested and undocumented, and required several tweaks before he could run it at the required 12 kHz PWM signals. His test motor was also undocumented, failing to run correctly when first hooked up. Fixing that issue meant having to disassemble the motor to check its internal wiring. Eventually, his efforts paid off, and he was able to safely run the TMP motor to confirm that his design worked.

With FPGA code, IGBT wiring and power supply issues sorted, the next step was to add a supervisory micro-controller, using an Arduino Nano. Its functions included interfacing with a touch screen LCD as a user interface, communicating with the FPGA module, and controlling several relays to switch power to the motor power supply, the roughing pump, TMP cooling fan, and a solenoid for the vacuum vent. Spindle current is calculated by measuring voltage drop across shunt resistors on the low side of the IGBT. Motor speed is measured using one of the motor hall sensors, and a thermistor provides motor temperature sensing. [Mark]’s PCB fabrication technique seems a bit different too. Using an Excellon drill file, he drills holes in a piece of plastic using a laser cutter to create a bare board, and then solders copper tracks by hand.

His initial tests at atmospheric pressure (although not recommended unless you monitor pump temperature), resulted in 7300 rpm while consuming about 7 Amps before he had to shut it down. In further tests, after adding a roughing pump to the test setup, he was able to spin the TMP to 20,000 rpm while it consumed 0.6 A. Obviously, the pump is rated to operate at a higher voltage, possibly 48 V based on the values mentioned in the TMP controller manual. The project is still “work in progress” as [Mark] hopes to eventually drive the pump up to its specified 60,000 rpm operating speed. What is not clear is what he eventually intends to do with this piece of exotic machinery. All he mentions is that “he has recently taken an interest in high-vacuum systems and is interested in exploring the high-vacuum world of electron guns.”

Maybe [Mark] can compare notes with the Open Source Turbomolecular Pump Controller that we featured some time back. And if you’d like to be a little bit more adventurous and build you own TMP, we got you covered with this DIY Everyman’s Turbomolecular Pump.

[Ben Eater]’s Breadboarding Tips

January 5, 2021 by Dan Maloney 32 Comments

A solderless breadboard is a place where ideas go to become real for the first time. Usually, this is a somewhat messy affair, with random jumpers flying all about the place, connecting components that can be quickly swapped to zero in on the right values, or to quickly change the circuit topology. Breadboards aren’t the place to make circuit artwork.

That is, however, not always the case, and we’ve seen more than a few examples from [Ben Eater] on breadboarding that approaches the circuit sculpture level of craftsmanship. And like any good craftsman, [Ben] has shared some of his breadboarding tips and tricks in a new video. Starting with a simple 555 blinkenlight project that’s wired up in the traditional anything-goes fashion, [Ben] walks us through his process for making a more presentation-worthy version.

His tools are high-quality but simple, with the wire strippers being the most crucial to good results. Surprisingly, [Ben] relies most heavily on the simple “scissors-style” strippers for their versatility, rather than the complicated semi-automatic tools. We found that to be the biggest take-home from the video, as well as the results of practice. [Ben] has done tons of this type of breadboarding before, which means when he “eyeballs” stripping 0.3 inches of insulation, he can do it down to a ten-thousandth precision.

Granted, there’s not much new here, but watching this video is a little like watching [Bob Ross] paint — relaxing and strangely compelling at the same time. You can get more of the same with pretty much any of his videos that we’ve covered, like this 6502 breadboard computer build. We’ve also seen [Eater]-inspired builds that are pretty impressive, like this full-8-bit breadboard computer.

Continue reading “[Ben Eater]’s Breadboarding Tips” →

Domino Layer Lets You Focus On Toppling

January 1, 2021 by Lewin Day 12 Comments

Knocking dominoes down is a fun pastime for a rainy afternoon, but setting them all up can be a drag. Thankfully, [Lewis] of [DIY Machines] has built a helpful machine to do the job for you, letting you focus on the fun part instead!

The machine is run by an Arduino Uno, that can be pre-programmed with a layout or controlled over Bluetooth in real time. It uses a geared-down DC motor to drive around a smooth surface, with a servo for steering. A second servo is used to turn a carousel loaded with up to 130 dominoes, allowing the machine to lay long runs without needing a refill. It’s designed to be easy to change so multiple carousels can be printed to quickly run courses of extended lengths.

The build is a great example of a machine capable of doing a tricky task with ease, thanks to 3D printing and smart design. We’re particularly impressed with the simple domino transport mechanism integrated into the drive system without requiring extra motors or servos. It’s not the first domino layer we’ve seen, either. Video after the break.

Continue reading “Domino Layer Lets You Focus On Toppling” →