i2c

201 Articles

Hackaday Prize Entry: MappyDot, A Micro Smart LiDAR Sensor

August 21, 2017 by 41 Comments

[Blecky]’s entry to the Hackaday Prize is MappyDot, a tiny board less than a square inch in size that holds a VL53L0X time-of-flight distance sensor and can measure distances of up to 2 meters.

MappyDot is more than just a breakout board; the ATMega328PB microcontroller on each PCB provides filtering, an easy to use  I2C interface, and automatically handles up to 112 boards connected in a bus. The idea is that one or a few MappyDots can be used by themselves, but managing a large number is just as easy. By dotting a device with multiple MappyDots pointing in different directions, a device could combine the readings to gain a LiDAR-like understanding of its physical environment. Its big numbers of MappyDots [Blecky] is going for, too: he just received a few panels of bare PCBs that he’ll soon be laboriously populating. The good news is, there aren’t that many components on each board.

It’s great to see open sourced projects and tools in which it is clear some thought has gone into making them flexible and easy to use. This means they are easier to incorporate into other work and helps make them a great contestant for the Hackaday Prize.

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A Beverage Cooler That Comes To You!

July 2, 2017 by 28 Comments

Feel like taking a long walk, but can’t be bothered with carrying your drinks? Have no fear, this  “Follow Me” Cooler Bot is here!

Really just a mobile platform with a cooler on top, the robot connects to smartphone via Bluetooth, following it using GPS. Making the platform involves a little woodworking skill, and an aluminium hub with a 3D-printed hub adapter connects the motors to a pair 6″ rubber wheels with a swivel caster mounted at the rear. A pocket in the platform’s base houses the electronics.

The Arduino Uno — via an L298n motor driver — controls two 12V DC, brushed and geared motors mounted with 3D printed brackets, while a Parallax PAM-7Q GPS Module in conjunction with an HMC 5883L compass help the robot keep its bearing. A duo of batteries power the motors and the electronics separately to prevent  any malfunctions.

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Hackaday Prize Entry: MakerNet

May 27, 2017 by 18 Comments

One of the biggest trends in whatever market ‘Maker’ stuff belongs to is the Legofication of electronics. Building electronics is hard, if you haven’t noticed. Anything that turns transmission lines, current loops, and RF wizardry into something a five-year-old can use has obvious applications to education. For his Hackaday Prize entry, [Jeremy Gilbert] is building a fast, intuitive, modular way to explore electronics. It’s easier to use than the 100-in-1 Radio Shack spring clip kits, and you can actually make useful projects with this system.

MakerNet is [Jeremy]’s solution to the problem of complicated electronics, Arduinos connected to breadboards with DuPont cables, and apparently, to actual electronic Lego sets. The core of this system is built around the Atmel SAM D21 microcontroller, an ARM Cortex-M0+ chip that has more than enough processing power for anything deserving of the ‘maker’ label. This mainboard connects to devices through what is basically an I2C bus. Each module in the system has an in and out header. A small SAM D11 (available for $1 USD) on each module handles all the communications.

Right now, [Jeremy] is experimenting with a dozen or so modules including a captouch board, an LED matrix, OLED display, rotary encoders, and lots of blinky LEDs. It’s just a prototype, but that’s exactly what we’re looking for at this stage of the Hackaday Prize. After looking at the video [Jeremy] produced (below), there’s a lot of promise here.

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Wireless Nunchuck R/C Remote!

April 10, 2017 by 5 Comments

[Dan], admirably rose to the occasion when his son wanted a new toy. Being a dedicated father — and instead of buying something new — he took the opportunity to abscond to his workbench to convert a Wiimote Nunchuck into a fully wireless controller for his son’s old r/c car — itself, gutted and rebuilt some years earlier.

Unpacking the nunchuck and corralling the I2C wires was simply done. From there, he combined a bit of code, an Arduino pro mini, and two 1K Ohm resistors to make use of an Aurel RTX-MID transceiver that had been lying around. Waste not, want not.

A TI Stellaris Launchpad is the smarts of the car itself, in concordance with a TB6612FNG motor controller. The two Solarbotics GM9 motors with some 3D printed gears give the car some much needed gusto.

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An Introduction To Differential I²C

March 31, 2017 by 45 Comments

A few weeks back, we talked about the no-nos of running I²C over long wires. For prototyping? Yes! But for a bulletproof production environment, this practice just won’t make the cut. This month I plucked my favorite solution from the bunch and gave it a spin. Specifically, I have put together a differential I²C (DI²C) setup with the PCA9615 to talk to a string of Bosch IMUs. Behold: an IMU Noodle is born! Grab yourself a cup of coffee and join me as I arm you with the nuts and bolts of DI²C so that you too can run I²C over long cables like a boss.

What’s so Schnazzy about Differential Signals?

There’s a host of ways to make I²C’s communication lines more noise resistant. From all of the choices we covered, I picked differential signals. They’re simple, fairly standardized, and just too elegant to ignore. Let’s take a moment for a brief “differential-signals-101” lecture. Hopefully, you’re already caffeinated! Continue reading “An Introduction To Differential I²C” →

Hacked IoT Switch Gains I2C Super Powers

March 27, 2017 by 50 Comments

Economies of scale and mass production bring us tons of stuff for not much money. And sometimes, that stuff is hackable. Case in point: the $5 Sonoff WiFi Smart Switch has an ESP8266 inside but the firmware isn’t very flexible. The device is equipped with the bare minimum 1 MB of SPI flash memory. Even worse, it doesn’t have the I2C ports extra pins exposed so that you can’t just connect up your own sensors and make them much more than just a switch. But that’s why we have soldering irons, right?

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Octosonar Is 8X Better Than Monosonar

February 25, 2017 by 29 Comments

The HC-SR04 sonar modules are available for a mere pittance and, with some coaxing, can do a pretty decent job of helping your robot measure the distance to the nearest wall. But when sellers on eBay are shipping these things in ten-packs, why would you stop at mounting just one or two on your ‘bot? Octosonar is a hardware and Arduino software library that’ll get you up and running with up to eight sonar sensors in short order.

Octosonar uses an I2C multiplexer to send the “start” trigger pulses, and an eight-way OR gate to return the “echo” signal back to the host microcontroller. The software library then sends the I2C command to select and trigger a sonar module, and a couple of interrupt routines watch the “echo” line to figure out the time of flight, and thus the distance.

Having two sonars on each side of a rectangular robot allows it move parallel to a wall in a straightforward fashion: steer toward or away from the wall until they match. Watch the video below for a demo of this very simple setup. (But also note where the robot’s 45-degree blind spot is: bump-bump-bump!)

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