Smooth Moves From Cheap Motors

November 16, 2018 by Bryan Cockfield 36 Comments

Building an electric motor isn’t hard or technically challenging, but these motors have very little in the way of control. A stepper motor is usually employed in applications that need precision, but adding this feature to a motor adds complexity and therefore cost. There is a small $3 stepper motor available, but the downside to this motor is that it’s not exactly the Cadillac of motors, nor was it intended to be. With some coaxing, though, [T-Kuhn] was able to get a lot out of this small, cheap motor.

To test out the motors, [T-Kuhn] built a small robotic arm. He began by programming his own pulse generating algorithm that mimics a sine wave in order to smooth out the movement of the motor. An Arduino isn’t fast enough to do these computations, though, so he upgraded to using the ESP32. He also was able to implement the inverse kinematics on his own. The result of all this work for a specific platform and motor type is a robotic arm that has a very low cost but delivers performance of much more expensive hardware.

The robot arm was built by [T-Kuhn] too, and all of the details on that build, as well as all the schematics and code, are available on the project site if you need a low-cost robot arm or a good stepper motor controller for a low cost. There are many other ways of getting the most out of other types of low-cost motors as well.

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Adding Bluetooth To Original SNES Controllers

October 10, 2018 by Tom Nardi 14 Comments

There’s a bunch of companies selling wireless Super Nintendo style controllers out there. You can go on Amazon and get any number of modern pads that at least kinda-sorta look like what came with Nintendo’s legendary 1990’s game console. They’ve got all kinds of bells and whistles, Bluetooth, USB-C, analog sticks, etc. But none of them are legitimate SNES controllers, and for some people that’s just not good enough.

[sjm4306] is one of those people. He wanted to add Bluetooth and some other modern niceties to a legitimate first-party SNES controller, so he picked up a broken one off of eBay and got to work grafting in his custom hardware. The final result works with Nintendo’s “Classic Edition” consoles, but the concept could also work with the original consoles as well as the computer if you prefer your classic games emulated.

A custom ATMEGA328P-powered board polls the controller’s SPI serial shift register in much the same way the original SNES would have. It then takes those button states and sends them out over UART with a HC-05 Bluetooth module. The controller is powered by a 330 mAh 3.7V battery, and a charging circuit allows for easily topping the controller off with a standard USB cable.

A particularly nice touch on the controller is the use of custom light pipes for the status LEDs. [sjm4306] made them by taking pieces of transparent PLA 3D printer filament, heating and flattening the end, and then sanding it smooth. This provides a diffusing effect on the light, and we’ve got to say it looks very good. Definitely a tip to file away for the future.

On the receiving side, this project was inspired by a custom NES Classic Edition Advantage controller we featured last year, and borrows the work creator [bbtinkerer] did to get his receiver hardware talking to the Classic console over I2C.

We’ve seen a number of projects which have added wireless functionality to the classic Super Nintendo controller, but most tend to be more invasive than this one. We like the idea of reading the controller’s original hardware rather than completely gutting it.

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Don’t Forget Your Mints When Using This Synthesizer

August 15, 2018 by Bryan Cockfield 11 Comments

While synthesizers in the music world are incredibly common, they’re not all keyboard-based instruments as you might be imagining. Especially if you’re trying to get a specific feel or sound from a synthesizer in order to mimic a real instrument, there might be a better style synth that you can use. One of these types is the breath controller, a synthesizer specifically built to mimic the sound of wind instruments using the actual breath from a physical person. Available breath controllers can be pricey, though, so [Andrey] built his own.

To build the synthesizer, [Andrey] used a melodica hose and mouthpiece connected to a pressure sensor. He then built a condenser circuit on a custom Arduino shield and plugged it all into an Arduino Mega (although he notes that this is a bit of overkill). From there, the Arduino needed to be programmed to act as a MIDI device and to interact with the pressure sensor, and he was well on his way to a wind instrument synthesizer.

The beauty of synthesizers is not just in their ability to match the look and sound of existing instruments but to do things beyond the realm of traditional instruments as well, sometimes for a greatly reduced price point.

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Electric Bike From The Ground Up

August 8, 2018 by Bryan Cockfield 21 Comments

Electric vehicles are getting more traction these days, but this trend is rolling towards us in more ways than just passenger vehicles. More and more bikes are being electrified too, since the cost of batteries has come down and people realize that they can get around town easily without having to pay the exorbitant price to own, fuel, and maintain a car. Of course there are turnkey ebikes, but those don’t interest us much around here. This ebike from [Andy] is a master class in how to build your own ebike.

Due to some health issues, [Andy] needed a little bit of assistance from an electric motor on his bike, but found out that the one he wanted wouldn’t fit his current bike quite right. He bought a frame from eBay with the right dimensions and assembled the bike from scratch. Not only that, but when it was time to put the battery together he sourced individual 18650 cells and built a custom battery for the bike. His build goes into great detail on how to do all of these things, so even if you need a lithium battery for another project this build might be worth a read.

If you’ve never been on an electric bike before, they’re a lot of fun to ride. They’re also extremely economical, and a good project too if you’re looking for an excuse to go buy a kit and get to work. You can get creative with the drivetrain too if you’d like to do something out of the box, such as this bike that was powered by AA batteries and a supercapacitor.

Explore Low-Energy Bluetooth By Gaming

July 13, 2018 by Bryan Cockfield 5 Comments

For several years now, a more energy-efficient version of Bluetooth has been available for use in certain wireless applications, although it hasn’t always been straightforward to use. Luckily now there’s a development platform for Bluetooth Low Energy (BLE) from Texas Instruments that makes using this protocol much easier, as [Markel] demonstrates with a homebrew video game controller.

The core of the project is of course the TI Launchpad with the BLE package, which uses a 32-bit ARM microcontroller running at 48 MHz. For this project, [Markel] also uses an Educational BoosterPack MKII, another TI device which resembles an NES controller. To get everything set up, though, he does have to do some hardware modifications to get everything to work properly but in the end he has a functioning wireless video game controller that can run for an incredibly long time on just four AA batteries.

If you’re building a retro gaming console, this isn’t too bad a product to get your system off the ground using modern technology disguised as an 8-bit-era controller. If you need some inspiration beyond the design of the controller, though, we have lots of examples to explore.

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Old Time Traffic Signal Revived With A Raspberry Pi Controller

July 12, 2018 by Dan Maloney 28 Comments

Anyone with even a passing familiarity with the classic animated shorts of the 1940s will recognize the traffic signal in the image above. Yes, such things actually existed in the real world, not just in the Looney world of [Bugs Bunny] et al. As sturdy as such devices were, they don’t last forever, though, which is why a restoration of this classic Acme traffic signal was necessary for a California museum. Yes, that Acme.

When you see a traffic signal from the early days of the automotive age like this one, it becomes quickly apparent how good the modern equivalent has become. Back in the day, with a mix of lights distributed all over the body of the signal, arms that extend out, and bells that ring when the state changes, it’s easy to see how things could get out of hand at an intersection. That complexity made the restoration project by [am1034481] and colleagues at the Southern California Traffic Museum all the more difficult. Each signal has three lights, a motor for the flag, and an annunciator bell, each requiring a relay. What’s more, the motor needs to run in both directions, so a reversing relay is needed, and the arm has a mechanism to keep it in position when motor power is removed, which needs yet another relay. With two signals, everything was doubled, so the new controller used a 16-channel relay board and a Raspberry Pi to run through various demos. To keep induced currents from wreaking havoc, zero-crossing solid state relays were used on the big AC motors and coils in the signal. It looks like a lot of work, but the end results are worth it.

Looking for more information on traffic signal controls? We talked about that a while back.

Launching Fireworks With Raspberry Pi This Fourth Of July

July 3, 2018 by Dan Maloney 7 Comments

It’s that time of year again in the United States, and the skies will soon be alight with pyrotechnic displays, both professional and amateur. Amazing fireworks are freely available, sometimes legally, sometimes not. For the enthusiasts that put on homebrew displays, though, the choice between watching your handiwork or paying attention to what you’re doing while running the show is a tough one. This Raspberry Pi fireworks show controller aims to fix that problem.

[netmagi] claims his yearly display is a modest affair, but this controller can address 24 channels, which would be a pretty big show in any neighborhood. Living inside an old wine box is a Raspberry Pi 3B+ and three 8-channel relay boards. Half of the relays are connected directly to breakouts on the end of a long wire that connect to the electric matches used to trigger the fireworks, while the rest of the contacts are connected to a wireless controller. The front panel sports a key switch for safety and a retro analog meter for keeping tabs on the sealed lead-acid battery that powers everything. [netmagi] even set the Pi up with WiFi so he can trigger the show from his phone, letting him watch the wonder unfold overhead. A few test shots are shown in the video below.

As much as we appreciate the DIY spirit, it goes without saying that some things are best left to the pros, and pyrotechnics is probably one of those things. Ever wonder how said pros pull it off? Here’s a behind-the-scenes look.

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