arduino

2862 Articles

SimpleSumo Bots Teach More Than Fighting

October 28, 2017 by 2 Comments

[MechEngineerMike] wrote in to share the enthusiasm over SimpleSumo, a series of open source, customizable robots he designed for mini-sumo battling and much more. For the unfamiliar, mini-sumo is a sport where two robots try to push each other out of a ring. [Mike]’s bots are simplified versions designed for education.

[Mike] was inspired by a video of some kids building mini-sumo bots who were doing anything and everything to personalize them. He vowed to make his own affordable, easy-to-build bots with education firmly in mind. His other major requirement? They had to be as easily customizable as that one potato-based toy that eventually came with a bucket of parts. As of this writing, there are 34 interchangeable accessories.

[Mike]’s first idea was to build the bots out of custom 3D-printed building blocks. He soon found it was too much work to print consistent blocks and switched to a modular cube-like design instead. SimpleSumo bots can do much more than just fight each other. [Mike] has written programs to make them flee from objects, follow lines, find objects and push them out of the ring, and beep with increasing frequency when an object is detected.

The bots are completely open source, but [Mike] sells kits for people who can’t print the parts themselves. He’s made a wealth of information available on his website including links to outside resources about mini-sumo, Arduino, programming, and 3D design. How about a complete series of assembly videos? First one is after the break.  Don’t know how to build a battle ring? He’s got that covered, too.

For a sumo bot that’s more brains than brawn, check out Zumo Red, the smart sumo.

Continue reading “SimpleSumo Bots Teach More Than Fighting” →

Tiny, Wearable 8-Bit VT100 Terminal

October 24, 2017 by 13 Comments

In the modern era of computing, the end-user is often quite far removed from the machine they’re using. At least in terms of abstraction levels, the user experience of most computers, smart phones, and the like are very far away from the zeros and ones. If you need to get down to that level though, you’ll have to make your way to a terminal somehow, and reminisce fondly about the days when everything was accessed through a serial line.

Nowadays, some harmless nostalgia is often accompanied by a challenge as well, as [Nick] demonstrated with his tiny serial terminal. It mimics the parsing and rendering of a VT100 console using an Arduino Uno and a 1″x1″ TFT screen. His goal was to make it wearable like a wristwatch would be, using two buttons as an HID device. With the size and simple interface, [Nick] also explores the possibility of mounting such a terminal to a pair of glasses.

While not everyone may want to interact with a serial terminal with only two buttons, it’s certainly a great demonstration of what is possible when it comes to implementing retro software in unique ways. There have been serial terminals implemented in many other unique places as well, such as old oscilloscopes and replicas from popular video games.

Using An Arduino To Re-Create A Computer’s Keyboard Decoder

October 22, 2017 by 19 Comments

[Max Breedon] found an old Apple IIe clone twenty years ago. He recently dug this Epson AP-200 out of the salvage heap and quickly discovered that the keyboard decoder chip was fried. The old chip was way too obscure to source a replacement — and soon this post will be the top Google result for the string, ‘C35224E’ — so he busted out his trusty UNO and created a replacement keyboard decoder.

Unlike the Apple II, where all the keyboard decoding happens on the keyboard, this clone used a dedicated chip on the main board. Although it’s a rare part that’s virtually ungoogleable, this chip’s architecture and pinout can be figured out by testing out every trace for continuity. After locating what looked like four data pins, he had the Arduino send signals onto the clone to see what characters popped up. That didn’t work, but it led him to idea that two of the wires were clock and data, and after a bit of experimenting figured out that the third pin was a latch enable of some sort that sent the character.

So, [Max] created an Arduino rig to do the same thing. The Arduino uses a shift register to interact with the keyboard’s 8×10 matrix, and the sketch translates any serial data it receives into the keypresses the clone is expecting. After prototyping with the UNO, [Max] hardwired an Arduino Nano (as well as the shift register) into a daughter board with pins extending into the old chip’s sockets. A permanent solution!

In addition to a weird keyboard controller that has been lost to the sands of time, this Apple IIe clone features a few more parts that are downright weird. There are two chips that are found in a few other Apple clones labeled STK 65301 and STK 65371, used as ASICs, MMUs, or a 20-IC expression of Wozzian brilliance condensed into custom silicon. There’s another weird chip in this clone, a 27c32 ROM loaded up with repetitive bits. There is no obvious 6502 code or strings in this ROM, so if anyone has an idea what this chip does, send [Max] a note.

Look What Came Out Of My USB Charger !

October 21, 2017 by 6 Comments

Quick Charge, Qualcomm’s power delivery over USB technology, was introduced in 2013 and has evolved over several versions offering increasing levels of power transfer. The current version — QCv3.0 — offers 18 W power at voltage levels between 3.6 V to 20 V.  Moreover, connected devices can negotiate and request any voltage between these two limits in 200 mV steps. After some tinkering, [Vincent Deconinck] succeeded in turning a Quick Charge 3.0 charger into a variable voltage power supply.

His blog post is a great introduction and walk through of the Quick Charge ecosystem. [Vincent] was motivated after reading about [Septillion] and [Hugatry]’s work on coaxing a QCv2.0 charger into a variable voltage source which could output either 5 V, 9 V or 12 V. He built upon their work and added QCv3.0 features to create a new QC3Control library.

To come to grips with what happens under the hood, he first obtained several QC2 and QC3 chargers, hooked them up to an Arduino, and ran the QC2Control library to see how they respond. There were some unexpected results; every time a 5 V handshake request was exchanged during QC mode, the chargers reset, their outputs dropped to 0 V and then settled back to a fixed 5 V output. After that, a fresh handshake was needed to revert to QC mode. Digging deeper, he learned that the Quick Charge system relies on specific control voltages being detected on the D+ and D- terminals of the USB port to determine mode and output voltage. These control voltages are generated using resistor networks connected to the microcontroller GPIO pins. After building a fresh resistor network designed to more closely produce the recommended control voltages, and then optimizing it further to use just two micro-controller pins, he was able to get it to work as expected. Armed with all of this information, he then proceeded to design the QC3Control library, available for download on GitHub.

Thanks to his new library and a dual output QC3 charger, he was able to generate the Jolly Wrencher on his Rigol, by getting the Arduino to quickly make voltage change requests.

Continue reading “Look What Came Out Of My USB Charger !” →

Hassle-Free Classical Conditioning For Honey Bees

October 18, 2017 by 10 Comments

When you’re sick or have a headache, you tend to see things a bit differently. An ill-feeling human will display a cognitive bias and expect the world to punish them further. The same is true of honey bees. They are intelligent creatures that exhibit a variety of life skills, such as decision-making and learning.

It was proven back in 2011 that honey bees will make more pessimistic decisions after being shaken in a way that simulates an attack by varroa destructor mites. The bees were trained to associate a reward of sugar-water with a particular odor and to associate foul-tasting punishment water with another odor—that of formic acid, a common treatment against varroa mites. When a third stimulus created by mixing the two odors was presented, the experimenters found that the aggravated bees were more likely to expect the bad odor. Sure enough, they kept their tongues in their mouths when they smelled the third odor. All the bees that weren’t shaken looked forward to sucking down a bit of sugar-water.

So, how does one judge a honey bee’s response? Whenever their antennae come in contact with something appetizing, they stick out their proboscis involuntarily to have a taste. This is called proboscis extension reflex (PER), and it’s the ingrained, day-one behavior that leads them to suck the nectar out of flower blossoms and regurgitate it to make honey.

[LJohann] is a behavioral biologist who wanted to test the effects of varroa mite treatment on bee-havior by itself, without agitating the bees. He built a testing apparatus to pump odors toward bees and judge their response which is shown in a few brief demo videos after the break. This device enables [LJohann] to restrain a bee, tantalize its antennae with sucrose, and pump a stimulus odor at its face on the cue of an LED and piezo buzzer. A fan mounted behind the bee helps clear the air of the previous scents. We especially like the use of a servo to swing the tube in and out of the bee’s face between tests.

[LJohann] and his colleagues concluded that the varroa mite treatment by itself does not make the bees pessimistic. This is great news for concerned apiarists who might be skeptical about using formic acid in the fight against the honey bee’s worst predator. Check out the brief demo videos after the break.

Hackaday has long been abuzz about bees whether they produce honey or not. We’ve covered many kinds of sweet projects like intelligent hives, remote hive weight monitoring, and man-made bee nest alternatives. Continue reading “Hassle-Free Classical Conditioning For Honey Bees” →

Click Your Heels Thrice, Hail A Cab Home

October 17, 2017 by 21 Comments

If Dorothy from The Wizard of Oz were to wake up in 2017, with her magic Ruby Slippers on her feet, she’d probably believe she had woken up in a magical world. But modern folks will need a little more magic to impress them. Like Clicking your heels thrice to get home with these Uber ruby slippers. [Hannah Joshua] was tasked by her employer to build a quirky maker project. She got an idea when a friend complained about having trouble hailing a cab at the end of a hard day at work.

[Hannah] started with ruby colored slippers with a platform toe and high heels to allow space to stuff in all the magic dust, err, electronic bits. The initial plan was to use an Arduino with a GSM/GPS shield but that would have needed a separate SIM card and data plan for the shoes. Instead, she opted for the 1Sheeld which connects to a smart phone over Bluetooth. The 1Sheeld gets access to all of the smart phone’s sensors including the GPS as well as the data connection. The Arduino and 1Sheeld are put in a cavity carved out in the toe section. The 9 V battery goes inside another cavity in the heel, where an activation switch is also installed. Three LED’s indicate when the shoe is active, the cab request is accepted, and when the cab is on its way.

The code is basic since this one of her first Arduino projects, but it gets the job done. It sends an http request to Uber’s API to request a cab. The destination is hard-coded, so the slippers only allow you to get from your current location to whatever destination is programmed. The GitHub repository provides code, as well as some additional information on construction. [Hannah] has also added notes explaining some of the design choices and things to take care about if you plan to build one of these magic slippers.

We covered the 1Sheeld when it was introduced several years back, and if you get your hands on one, try building this Hand Waving Door Unlocker.

Continue reading “Click Your Heels Thrice, Hail A Cab Home” →

TeensyStep – Fast Stepper Library For Teensy

October 17, 2017 by 27 Comments

The Teensy platform is very popular with hackers — and rightly so. Teensys are available in 8-bit and 32-bit versions, the hardware has a bread-board friendly footprint, there are a ton of Teensy libraries available, and they can also run standard Arduino libraries. Want to blink a lot of LED’s? At very fast update rates? How about MIDI? Or USB-HID devices? The Teensy can handle just about anything you throw at it. Driving motors is easy using the standard Arduino libraries such as Stepper, AccelStepper or Arduino Stepper Library.

But if you want to move multiple motors at high micro-stepping speeds, either independently or synchronously and without step loss, these standard libraries become bottlenecks. [Lutz Niggl]’s new TeensyStep fast stepper control library offers a great improvement in performance when driving steppers at high speed. It works with all of the Teensy 3.x boards, and is able to handle accelerated synchronous and independent moves of multiple motors at the high pulse rates required for micro-stepping drivers.

The library can be used to turn motors at up to 300,000 steps/sec which works out to an incredible 5625 rpm at 1/16 th micro-stepping. In the demo video below, you can see him push two motors at 160,000 steps/sec — that’s 3000 rpm — without the two arms colliding. Motors can be moved either independently or synchronously. Synchronous movement uses Bresenham’s line algorithm to plan motor movements based on start and end positions. While doing a synchronous move, it can also run other motors independently. The TeensyStep library uses two class objects. The Stepper class does not require any system resources other than 56 bytes of memory. The StepControl class requires one IntervallTimer and two channels of a FTM  (FlexTimer Module) timer. Since all supported Teensys implement four PIT timers and a FTM0 module with eight timer channels, the usage is limited to four StepControl objects existing at the same time. Check out [Lutz]’s project page for some performance figures.

As a comparison, check out Better Stepping with 8-bit Micros — this approach uses DMA channels as high-speed counters, with each count sending a pulse to the motor.

Thanks to [Paul Stoffregen] for tipping us off about this new library. Continue reading “TeensyStep – Fast Stepper Library For Teensy” →