Arduino Hacks

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Numpy Comes To Micro Python

October 29, 2019 by 12 Comments

[Zoltán] sends in his very interesting implementation of a NumPy-like library for micropython called ulab.

He had a project in MicroPython that needed a very fast FFT on a micro controller, and was looking at all of the options when it occurred to him that a more structured approach like the one we all know and love in CPython would be possible on a micro controller too. He thus ended up with a python library that could do the FFT 50 times faster than the the pure Python implementation while providing all the readability and ease of use benefits that NumPy and Python together provide.

As cool as this is, what’s even cooler is that [Zoltan] wrote excellent documentation on the use of the library. Not only can this documentation be used for his library, but it provides many excellent examples of how to use MicroPython itself.

We really recommend that fans of Python and NumPy give this one a look over!

Electricity Makes Soft Robotics More Like Us Meatbags

October 28, 2019 by 6 Comments

Building a future where robots work alongside humans relies heavily on soft robotics. Typically this means there will be an air compressor or a hydraulic system nearby, taking up precious space. But it doesn’t have to.

Engineers at the UC-San Diego Jacobs School have created a soft robotics system that uses electricity to control flexible actuators, much like our brains move our muscles. It works like this: sheets of heat-sensitive liquid crystal elastomer are sandwiched between two layers of standard elastomer. These layers are rolled into cylinders that can twist and bend in different directions depending on which of its six element(s) get electricity. Light up all six, and the tube contracts, forming the foundation for a good gripper. The team also built a tiny walker, pictured above.

The project is still in its infancy, so the actuators are slow to bend and even slower to return to their original shape, but it’s still a great start. Imagine all the soft robotic projects that can get off the ground without being shackled by the bulk and weight of an air compressor or fluid handling system. Watch it do various sped-up things after the break, like claw-machine gripping a bottle of chocolate rocks.

Speaking of delicious candy, edible soft robotics is totally a thing.

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Haptic Glove Controls Robot Hand Wirelessly

October 25, 2019 by No comments

[Miller] wanted to practice a bit with some wireless modules and wound up creating a robotic hand he could teleoperate with the help of a haptic glove. It lookes highly reproducible, as you can see the video, below the break.

The glove uses an Arduino’s analog to digital converter to read some flex sensors. Commercial flex sensors are pretty expensive, so he experimented with some homemade sensors. The ones with tin foil and graphite didn’t work well, but using some bent can metal worked better despite not having good resolution.

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Beat The Streets With This Text Spraying Robot

October 25, 2019 by 25 Comments

In the midst of striking for climate change awareness, you may need some extra hands. That’s what [Anred Zynch] thought when they built Strettexter, the text-spraying writing robot that sprays onto streets.

The machine is loaded with 8 spray cans placed into a wooden box (a stop line with a wooden ledge to prevent the cans from falling out) and is fixed on top of a skateboard. It uses a PWN/Servo shield soldered onto an Arduino Uno connected to 8 servo motors (TowerPro SG90s) to control each of the spray bottles. A table converts every character into 5×8 bit fonts to fit the size of the spraying module. The device also includes a safety switch, as well as an encoder for measuring the horizontal distance traveled.

The Strettexter is activated by pulling on the skateboard once it’s been set up and connected to power (for portability, it uses a 8000mAh power bank). In its current configuration, the words stretch out pretty long, but some additional testing will probably lead to better results depending on the constraints of your canvas. The shorter the words, the more difficult it is for the white text to be legible, since there is significant spacing between printed bits.

We don’t condone public vandalism, so use this hack at your own discretion.

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Hang Ten With Help From The Surf Window

October 24, 2019 by 6 Comments

Unless you live in a special, unique place like Hawaii or Costa Rica it’s unlikely you’ll be able to surf every day. It’s not easy to plan surf sessions or even surf trips to most locations because the weather conditions will need to be just right. Not only the wave height (swell) but also the wind speed and direction, tide, water and air temperature, and even amount and type of marine life present can all impact your surf session. You’ll want something which can easily tell you right away if conditions are good.

This project from [luke] is called the Surf Window shows the surf conditions at the local beach with just one glance. Made out of various pieces of wood, each part represents one of the weather conditions at the beach. A rotating seagull gives the wind direction, for example, and the wave height is represented by 3D, moving waves. All of the parts are connected with various motors and linkages to an Arduino Mega +WiFi R3 which grabs all of its information from Magicseaweed, a surf forecasting site.

The Surf Window can show the current conditions at virtually any surfable beach in the world, so if you really want to know how Jaws, Mavericks, or even Reef Road is breaking right now, you could use this to give you a more nuanced look. Don’t forget to take the correct board for the conditions!

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Daisy Chained Seven Segment Art Display

October 23, 2019 by 8 Comments


This seven segment art display makes use of a 81 seven segment red common cathode LED displays. The LEDs are arranged onto 100x100mm boards that each contain an Arduino Nano and 9 seven segment displays, daisy chained through three-pin headers located on the sides of the boards. The pins (power, ground, and serial) provide the signals necessary for propagating a program across each of the connected boards.

The first board – with two Arduino Nanos – sends instructions for which digits to light and drives the display, sending the instructions over to the next board on the chain.

In a multiplexed arrangement, a single Arduino Nano is able to drive up to 12 seven segment displays, but only 9 needed to be driven for the program, keeping D13’s built in LED and the serial pins free. Since no resistors are featured on the boards, current limiting is done through software. This was inspired by the Bubble LED displays on the Sinclair Scientific Calculator, and was done in order to achieve a greater brightness by controlling the current through the duty cycle.

The time between digits lighting up is 2ms, giving them some time to cool down. The animations in the demos featured falling and incrementing digits, as well as a random number generator using a linear feedback shift register.

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