Trinket Uses RF To Track You Through The House

January 24, 2015 by 52 Comments

If you carry a cell phone with GPS, you always know where you are on the planet. But what about inside buildings or even your own home? Knowing if you’re in the kitchen or the living room would be a great feature for home automation systems. Lights could come on as you enter the room and your music could follow you on the home audio system. This is exactly the what [Eric] is working on with his Radiolocation using a Pocket Size Transceiver project. [Eric] started this project as an entry in the Trinket Everyday Carry Contest. He didn’t make the top 3, but was one of the fierce competitors who made the competition very hard to judge!

The heart of the project is determining Time Of Flight (TOF) for a radio signal. Since radio waves move at the speed of light, this is no small feat for an Arduino based design! [Eric] isn’t re-inventing the wheel though – he’s basing his design on several research papers, which he’s linked to his project description. Time of flight calculations get easier to handle when calculating round trip times rather than one way. To handle this, one or more base stations send out pings, which are received and returned by small transponders worn by a user. By averaging over many round trip transmissions, a distance estimation can be calculated.

[Eric] used a Pro Trinket as his mobile transponder, while an Arduino Micro with it’s 16 bit counter acted as the base station. For RF, he used the popular  Nordic nRF24L01+ 2.4 GHz transceiver modules. Even with this simple hardware, he’s achieved great results. So far he can display distance between base and transponder on a graph. Not bad for a DIY transponder so small if fits in a 2xAAA battery case! [Eric’s] next task is working through multipath issues, and testing out multiple base stations.

Click past the break to see [Eric’s] project in action!

Continue reading “Trinket Uses RF To Track You Through The House” →

joystick plus arduino

Arduino + Servo + Scotch Tape == An Interesting Conversation

January 24, 2015 by 41 Comments

If one could temporarily remove their sense of humor and cast a serious look into a Rube Goldberg machine, they would not say to themselves “well that looks simple.” Indeed, it would almost always be the case that one would find themselves asking “why all the complexity for such a simple task?”

Too often in hacking are we guilty of making things more complicated than they really need to be. Maybe it’s because we can see many different paths to a single destination. Maybe it’s because we want to explore a specific path, even though we know it might be a little harder to tread. Maybe it’s just because we can.

rubegoldberg

But imagine approaching a hack as simply a means to an end. Imagine if you did not have all of that knowledge in your head. All of those tools at your disposal. How would this change your approach? When [yavin427] decided to automate the leveling up process in his favorite video game, odds are he had never taken a game controller apart. Had never touched an oscilloscope. Indeed, he might have no knowledge of what a transistor or microcontroller even is. While many of our readers would have taken the more difficult path and tapped directly into the TTL of the controller to achieve maximum efficiency; it is most likely that [yavin427] would not have known how to do this, and thus would not have seen the many other paths to his end goal that would have been obvious to us. Yet he achieved his end goal. And he did it far easier and with less complication than many of us would have done.

Thoughts?

Continue reading “Arduino + Servo + Scotch Tape == An Interesting Conversation” →

PS3 Controller

Get Better At Mortal Kombat By Hacking Your PS3 Controller

January 24, 2015 by 12 Comments

Fighting games like Mortal Kombat provide you with a variety of different available moves. These include kicks, punches, grabs, etc. They also normally include various combination moves you can perform. These combo moves require you to press the proper buttons in the correct order and also require you to time the presses correctly. [Egzola] realized that he could just hack his controller to simulate the button presses for him. This bypasses the learning curve and allows him to perform more complicated combinations with just the press of a single button.

[Egzola] started by taking apart his Playstation 3 controller. There were two PCB’s inside connected by a ribbon cable. Luckily, each individual pad for this cable was labeled with the corresponding controller button. This made it extremely simple to hack the controller. [Egzola] soldered his own wires to each of these pads. Each wire is a different color. The wires then go to two different connectors to make them easier to hook up to a bread board.

Each wire is then broken out on the breadboard. The signal from each button is run through a 4n25 optoisolator. From there the signal makes its way back to various Arduino pins. The 4n25 chips keeps the controller circuit isolated from the Arduino’s electrical circuit. The Arduino also has two push buttons connected to it. These buttons are mounted to the PS3 controller.

Now when [Egzola] presses one of the buttons, the Arduino senses the button press and simulates pressing the various controller buttons in a pre-programmed order. The result is a devastating combination move that would normally require practice and repetition to remember. You might say that [Egzola] could have spent his time just learning the moves, but that wasn’t really the point was it? Check out the video below for a demonstration. Continue reading “Get Better At Mortal Kombat By Hacking Your PS3 Controller” →

A Primer On Buck (and Boost) Converters

January 24, 2015 by 13 Comments

We all know that the reason the electrical system uses alternating current is because it’s easy to step the voltage up and down using a transformer, a feature which just isn’t possible with a DC system… or is it? Perhaps you’ve heard of mysterious DC-DC transformers before but never really wanted to look at the wizardry that makes them possible. Now, SparkFun Director of Engineering [Pete Dokter] has a tutorial which explains how these mysterious devices work.

Known as buck converters if they step the input voltage down and boost converters if they step the voltage up, [Pete] explains how these circuits exploit the properties of an inductor to resist changes in current flow. He goes into exquisite detail to explain how components like transistors or MOSFETs are used to switch the current flow to the inductor very rapidly, and just exactly what happens to the magnetic field which makes these devices possible.

The video gives a good amount of background knowledge if you’ve always wanted to understand these devices a little bit better. There are also a few projects floating around that exploit these devices, such as one that uses an AVR microcontroller to perform the switching for a small circuit, or another that uses the interesting properties of these circuits to follow the I-V curve of a solar panel to help charge a bank of batteries. The possibilities are endless!

Continue reading “A Primer On Buck (and Boost) Converters” →

NES Controller

Turning A Classic NES Controller Into A Bluetooth Controller

January 23, 2015 by 12 Comments

[Pietronet] is like many of us in that he enjoys playing some classic console video games from time to time. He usually plays them on his PC using a Wiimote as a controller. The Wiimote has most of the classic buttons in a comfortable configuration. Plus, it’s got Bluetooth built-in, which makes it easy to pair up to your PC. [Pietronet] decided to take it a step further, though. He managed to cram all of the guts from a Wiimote inside of the original NES controller for a more authentic feel.

The first step was to crack open the Wiimote and locate pads for each button. Once they were located, [Pietronet] used a Dremel to cut the board into a smaller size. He cut off part of the circuit board that contained the directional pad as well as the connector for the nunchuck. Next he had to solder very thin wires to each of the button pads he located earlier.

The original NES controller has a very limited number of buttons, and [Pietronet] wanted to modify the original controller as little as possible. Therefore, he attached a magnetic reed switch to the Wiimote’s sync button. This way if he ever needs to sync the Wiimote to a new console, he can do it by holding a magnet in the right place. This is a function that isn’t often used, so the inconvenience should be negligible.

The next step was to connect the buttons from the original NES controller up to the wires that were added to the Wiimote. [Pietronet] left the original circuit board mostly intact. He did have to cut a small chunk of it away in order to make room for two AAA batteries, but this didn’t affect the functionality of the controller.

The inside of the NES controller had to be cleaned out of various standoffs and plastic bits to make room for all of the extra components. The Wiimote has an LED to indicate that the controller is connected properly. [Pietronet] soldered a red SMD LED in its place on the end of two thin wires. This LED was then placed on the bottom left side of the directional pad. It’s visible through a translucent filter. This allows [Pietronet] to see when the NES controller is synced up properly.

The case fits back together and everything is held in place. The result is what looks and feels like a classic NES controller, only this one has Bluetooth connectivity and a vibration motor. Check out the video demonstration below to get an idea of what it looks like in use. Continue reading “Turning A Classic NES Controller Into A Bluetooth Controller” →

A low cost power supply unit with displays

A Low Cost Bench Supply

January 23, 2015 by 27 Comments

Everyone needs a power supply on their bench, but a standard lab supply isn’t cheap. [ludzinc]’s PSU Console is a cheap alternative, which provides the basic features you’d expect in a lab supply.

The basis of this PSU is a DC/DC module based on the LM2596 step down switching regulator. These modules cost less than a single LM2596, but have all the required components for a buck DC/DC converter. Sure, they might not last forever, and they’re not the most efficient regulators, but the price is right.

The front panel has four displays for voltage and current, which are just low cost voltmeter displays. The potentiometers are used for adjusting the voltage of the DC/DC, and controlling the current limiter. This limiter monitors current through a shunt, and shuts off a MOSFET when the limit is exceeded.

The final product looks like something that’s ready for daily use, and was much cheaper than most supplies with these features. These low cost DC/DC modules are worth a look if you’re considering a similar build.

LVBots CES Open House: Tabletop Challenge And Clothes Bot

January 23, 2015 by 3 Comments

LVBots, a club for robot building enthusiasts in Las Vegas, held an open house the week of CES. This was the only trip [Sophi] and I took away from the conference halls of The Strip and it was a blast! The group holds meetings twice a month in a space provided by Pololu — a well-known robotics and electronics manufacturer headquartered just south of McCarran International Airport.

[Claire] demonstrating robotic closet demo and app
The mechanized racks of the automated closet
Line-following robot demonstration
Sumo robots about to rumble

Before the formal part of the gathering started there were several builds being shown off. [Claire] and [Brian] recently participated in an AT&T sponsored hackathon. Their creation is a robotic closet. The system involves moving racks of clothing which are tracked by a smartphone app. Interesting features discussed for the software include monitoring when each garment was last worn, last washed, and if it is appropriate for current weather conditions. Dig into the code in their repo.

In other parts of the room a pair of line-following robots did their thing, and a couple of sumo-bots competed to push each other out of the ring. A large group was gathered around the projector watching videos of robots of all types, brainstorming about the difficult parts, how they were overcome, and how these methods may be applied to their own build. I can attest that hanging with a group of people who are trying to cue up the most amazing robot demonstrations makes for amazing viewing!

As the organized part of the meeting began I was delighted to hear about a standing challenge from the LVbots group. The Tabletop challenge has multiple phases that serve to encourage builders to start modestly and then iterate to achieve new goals:

Phase 0: bring a robot to LVBots
Phase 1: travel back and forth without falling off
Phase 2: find an object and push it off
Phase 3: push object into a goal

[Nathan Bryant] and robot
[Joe Carson] and robot

[Nathan Bryant] was one of the two robot builders trying out the challenge on this night. He built this hexapod from balsa wood and three servo motors and was testing Phase 1. The bot includes a sensor dangling out in front of the robot to detect then the table surface is no long below. At that point it backs up a few steps, turns in place, and proceeds in the opposite direction. [Nathan] mentions that he worked out all the movements in a spreadsheet and that future firmware upgrades will dramatically increase the speed at which the bot moves. We love the audible cadence of the bot which is easily observed in the video above. At one point a leg dangles over the edge and it looks like [Nathan] pushed the bot back but I don’t remember him actually touching it so I’m calling this a trick of camera angle.

One phase further in the Tabletop Challenge is [Joe Carson]. He exhibited a wheeled robot he’s been working on that includes a gripper arm on the front. The robot looks around the table for a predefined color, in this case provided by a highlighting marker. When found the bot approaches, grips, and then proceeds to move the marker over the void where it is dropped out of existence; at least from the robot’s point of view.