Lego Minifig Multimeter Makes Resistor Sorting A Lot More Fun

March 17, 2011 by Mike Nathan 21 Comments

lego_minifig_multimeter

While there’s typically not much room on our work bench for toys, [David] over at Robot Room has put together a pretty cool multimeter for which we would make an exception.

His Lego Minifig multimeter is constructed using mostly standard off-the-shelf Legos, and a pair of Minifigs he modified to suit his needs. Translucent Minifig heads were sourced online to allow the neck-mounted LEDs to shine through, and each of the bodies were drilled out in several places to accommodate the wires he uses to take measurements.

The multimeter will display the resistance of any item from 10 – 10,000,000 Ω, as well as measure the voltage of any battery you can manage to fit under the Minifig’s metal wrench. The multimeter takes measurements using an ATmega168, and relays that data through a serial to USB converter connected to a nearby computer. The computer is host to a .NET application he wrote which displays and speaks both the resistance and voltage values.

Keep reading to see a quick video walkthrough and a demonstration of the multimeter at work.

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Sleek Numitron Clock Tells The Time And Temperature

March 13, 2011 by Mike Nathan 6 Comments

Instructables user [janw] is a big fan of nixie clocks, but he had never built one before. He decided he would rather start small and build a clock using numitron tubes first, before moving to nixies. He preferred the simpler tubes due to their much lower voltage requirements and the fact that he would not have to use any specialized power supply for his project.

His clock serves double-duty, functioning as a thermometer as well. Timekeeping is regulated with a DS12307, and temperature is monitored using a DS18B20 single wire sensor – both of which are pretty common in these sorts of projects. Both are wired to an Atmega48 MCU which serves as the brain of the clock.

The numitrons were mounted in a handsome 5-layer milled acrylate stand with a pair of buttons mounted on the bottom which allow him to set the time. It really is a spectacular looking timepiece, and a great first effort on [janw’s] part.

Be sure to stick around to see a video of the clock in action.

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Amazing Backyard Rocket Ship Tree House

February 21, 2011 by Mike Nathan 26 Comments

Ravenna_Ultra-Low-Altitude_Vehicle

If you thought you had a cool tree house as a kid, think again. Tasked with landscaping his back yard and building a tree house for his son, [Jon] decided to go all out and build him a rocket ship instead.

Rising 15 feet into the Seattle skyline, the tree house known as the Ravenna Ultra-Low-Altitude Vehicle (RULAV), is sure to be the envy of every kid in the neighborhood. [Jon] and a friend worked for well over a year on their creation, welding, grinding, painting, and riveting their way along. After the structure was built, they fabricated some custom PCBs, using them to build the ship’s 14 control panels. The entire operation is controlled by a custom OS built to run on the three ATmega MCUs that manage operations.

Not content with just a handful of knobs and switches, the ship contains over 800 LEDs among its laundry list of electronics goodies. Compressed air is used to shoot water from positioning “thrusters”, while a paint mixer spins under the ship to simulate the rough and bumpy nature of space travel. The simulated launches are capped off with plenty of authentic NASA-style audio and a sub woofer that gives everything a deep, resonating rumble.

The project is truly amazing, and a ton of work went into every little detail in order to make this the most spectacular tree house ever seen. [Jon] definitely takes the award for “Coolest Dad Ever” for this build, even we’re jealous!

The pictures certainly don’t do it justice, so be sure to check out the video below for a quick introduction and demo of this awesome project.

Thanks to [Jeremy Elson] for the tip.

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Analog To Digital Converter Build

February 20, 2011 by Mike Nathan 13 Comments

analogue_digital_converter

[Daniel Garcia] sent us a quick tutorial he put together demonstrating how to use an ATmega168 to perform analog to digital conversions. This timely tutorial would make for a nice complimentary project for those of you who decided to build your own digital to analog converter after reading our post from a few days ago.

The ATmega168 has six pins that are typically used for digital I/O, but they can be used for analog input as well. In his example, he uses a trimpot as an analog input device, connecting it to one of the aforementioned analog pins. Its value is returned as a 16-bit number which is then displayed on the attached LCD. The LCD display and the breadboard layout used in this project are covered in his previous writeups, so be sure to give those a read through before working through this tutorial.

Simple Household Status System

February 18, 2011 by Mike Nathan 20 Comments

The-Household-Informer

[BrianH] decided that he no longer wanted to venture outside on cold or rainy days just to check if the mail had come, so he built himself a notification system that would alert him if the postman had stopped by. Additionally, he admits to being forgetful on occasion and wanted a way to monitor whether or not he forgot to close the garage door. His Instructable details how he accomplished both of these tasks with the household monitor he built around an ATmega168. His project uses a mailbox mounted photoresistor to determine when the mailbox has been opened, and a reed switch that is triggered when the garage door has been opened. If either of these things occur, a beep is emitted from his notifier, and the appropriate status LED is lit. Simply monitoring whether the garage door has been opened is not all that helpful, so he programmed his notifier to beep persistently at 10-minute intervals if the garage has been left open for more than an hour.

His hack is pretty useful, but he does mention that there is an inordinate amount of wiring that needs to be laid, citing his driveway repaving as a great opportunity to do so.

Voice-controlled Rolling Robot

February 16, 2011 by Mike Nathan 13 Comments

rolling_voice_controlled_robot

[societyofrobots] recently posted an Instructable on how to build a voice controlled robot in just a few hours time. This robot isn’t particularly cheap, weighing in at about $230, but it is a fun project if you have the means. The bot is driven around by a pair of servos, taking their directions from an Axon II MCU. A VRbot voice recognition module is used to listen for commands, enabling the user to record up to 32 custom triggers for directing the robot.

All of the source code for the robot is included, as well as instructions on how to get started programing the microcontroller. The code provides some basic functionality, but there’s likely plenty more that can be done with the powerful on-board ATmega460. While this robot would make for a great beginner/intermediate project as-is, it should be noted that [societyofrobots] manufactures and sells the Axon II, so this Instructable is half guide/half self-promotion. Have any of you had experience with the Axon II? Let us know what you think.

Keep reading to see a video of the build process as well as the robot doing its thing.

Thanks, [Bill Porter].

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Rechargeable Battery Capacity Tester

February 10, 2011 by Mike Nathan 21 Comments

Rechargeable-Battery-Capacity-Tester

If you are like most people, you likely have a mixed pile of rechargeable batteries sitting around with no idea as to what kind of charge they can hold. You could watch a voltmeter for a few hours while you drain each and every battery, noting when it drops below its stated voltage – but then again, you have a life. Instead of wasting away in front of his multimeter, [BrianH] decided he would build an automated battery capacity tester to do the job for him.

He created a simple circuit that drains any AA battery, NiMh or NiCd, and records its useful capacity in milliamp hours. Since the ATMega168 microcontroller used has 6 analog/digital converters on board, he figured that he might as well design his tester to measure the capacity of three batteries simultaneously. [BrianH] wired the meter up to an old Nokia LCD, then moved his project to a perfboarded ATMega, freeing up his Arduino for other tasks. Once he had things reassembled, he packed it all into a handsome wooden box.

His writeup is chock full of details and source code, so be sure to check it out. We have video of the charger in action after the jump.

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