Arduino Gives Your Toilet Options

August 9, 2014 by Bryan Cockfield 60 Comments

toilet water saver

With the severe drought going on in California with no end in sight, [TVMiller] decided he could put an Arduino and a toilet together to try and save at least a few gallons of water per day. The invention fills a toilet to the minimum level, saving around two gallons per day for the average “user”.

A typical toilet functions by using gravity and moving water to create a vacuum, sucking the waste down and out of the toilet. As long as there is nothing, uh, solid in the bowl, the toilet will be able to function on the reduced amount of water. The Arduino cuts the flow of water off before the toilet fills up the entire way.

In the event that anyone -ahem- needs the toilet’s full capacity, there is a button connected to the Arduino that fills the reservoir to capacity. [TVMiller] notes that if 1,825 hackers installed this device on their toilets, we could save a million gallons of water per year and be well on our way to saving the planet.

The project site is full of more information and puns for your viewing pleasure. We might suggest that the “2” button would be very easy to integrate with the toilet terror level indicator as well.

Hacklet #10 Cryptography And Reverse Engineering

August 8, 2014 by Adam Fabio 25 Comments

In honor of DEFCON, this week we’re looking at some cryptography and reverse engineering projects over at Hackaday.io Every hacker loves a hardware puzzle, and [Tom] has created a tool to make those puzzles. His Hardware Reverse Engineering Learning Platform consists of a shield with two ATmega328 chips and an I2C EEPROM. The two Atmel chips share a data bus and I2C lines. Right in the middle of all this is an ST Morpho connector, which allows an ST Nucleo board to act as a sniffer. The platform allows anyone to create a reverse engineering challenge! To successfully reverse engineer a board, it sure helps to have good tools. [coflynn] is giving that to us in spaces with The ChipWhisperer. ChipWhisperer is an open source security research platform. The heart of the system is a Xilinx Spartan 6 FPGA. The FPGA allows very high speed operations for things like VCC and clock glitching. ChipWhisperer is an entire ecosystem of boards – from LNA blocks to field probes. The entire system is controlled from an easy to use GUI. The end result is a powerful tool for hardware attacks. On the Encryption side of the house, we start by keeping the Feds at bay. The [Sector67] hackerspace has collectively created NSA AWAY. NSA AWAY is a simple method of sending secure messages over an insecure medium – such as email. A one-time use pad is stored on two SD cards, which are used by two Android devices. The message sender uses an Android device to encrypt the message. On the receive side, the message can be decoded simply by pointing an android device’s camera at the encrypted data. So easy, even a grandparent could do it! Next up is [Josh’s] Bury it under the noise floor. “Bury it” is an education for cryptography in general, and steganographic software in particular. [Josh] explains how to use AES-256 encryption, password hashing, and other common techniques. He then introduces steganography by showing how to hide an encrypted message inside an image. Anyone who participated in Hackaday’s ARG build up to The Hackaday Prize will recognize this technique. [yago] gives us encrypted voice communications with his ZRTP Hardphone. The hardphone implements the ZRTP, a protocol for encrypted voice over IP communications. The protocol is implemented by a Raspberry Pi using a couple of USB sound cards. User interface is a 16×2 Line character LCD, a membrane keypad, and of course a phone handset. Don’t forget that you need to build two units,or whoever you’re trying to call will be rather confused!

Finally we have the Mooltipass. Developed right here on Hackaday by [Mathieu Stephan] and the community at large, Mooltipass is a secure password storage system. All your passwords can be stored fully AES-256 encrypted, with a Smart Card key. Under the hood, Mooltipass uses an Arduino compatible ATmega32U4 microcontroller. UI is through a OLED screen and touch controls. That’s it for this week! Be sure to check out next week’s Hacklet, when we bring you more of the best from Hackaday.io!

The Fridge Hacking Guide By BrewPi

August 3, 2014 by Matt Terndrup 20 Comments

brewpi-fridge-conversion-51

The team behind BrewPi are at it again! This time they have created an online guide showing how to convert a min-fridge into a Raspberry Pi & Arduino controlled fermentation chamber. In it, they describe 3 possible options:

Option 1: Make a simple switched power cord, without hacking into the fridge electronics.
Option 2: Make a switched power cord, but also override or remove the thermostat.
Option 3: Rip out the thermostat and fully integrate the SSRs into your fridge (which is what [Koen] and [Elco] did).

First things first though. They had to clean the fridge. And depending on where they got it or how long it has been unplugged for, the inside might have been pretty rank and disgusting from mold growing out of every corner. This took a good hour or so to clean properly lest the brewing process get infected with external grossness. This is all worth it because a well-controlled fermentation chamber results in a superior batch of beer.

They put their laser cut case on top of the fridge, holding an LCD, Raspberry Pi, Arduino and the BrewPi Arduino shield. The Arduino reads the temperature sensors inside the fridge, the beer and the ambient temperature. Then it controls the SSRs they added to switch the compressor and a heater. Then, the cables were routed through the fridge and take control of the compressor.

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Repurposed Laptop Batteries With A Twist

August 3, 2014 by Bryan Cockfield 14 Comments

Arduino with lithium ion battery

Lithium ion batteries are becoming more and more common these days, but some of the larger capacity batteries can still carry a pretty hefty price tag. After finding Acer’s motherboard schematics online and doing a little reverse-engineering, [Tiziano] has found a way to reuse batteries from his dead laptop, not only saving the batteries from the landfill but also cutting costs on future projects.

These types of batteries have been used for many things in the past, but what makes this project different is that [Tiziano] is able to monitor the status of the batteries and charge them using I2C with an Arduino and a separate power supply, freeing the batteries from the bonds of the now-useless laptop.

With this level of communication between the microcontroller and the battery pack, there is little chance of the batteries catching on fire when they’re used in another project. Since the Arduino can also monitor the current amount of charge in the batteries, there is also a reduced risk that they will be damaged from under- or over-charging.

This wasn’t just as simple as hooking up the positive and negative leads of a power supply to the battery. [Tiziano] also had to model the internal resistance of the motherboard that the battery expects to see, and get the supply voltage just right so the battery’s safety protocols wouldn’t kick in to prevent them from charging. After a few other hurdles were jumped, [Tiziano] now has a large capacity lithium ion battery at his disposal for any future projects.

Solar Powered Lawn Mower Cuts The Grass So You Don’t Have To

August 1, 2014 by Matt Terndrup 23 Comments

MowerFea2

It takes a lot of power and energy to keep grass levels down to an appropriate level; especially when it’s hot out. If cool glasses of lemonade aren’t around, the task at hand may not be completed any time soon causing the unkempt blades of green (or yellow) vegetation outside to continue their path of growth towards the sun.

Instead of braving the oven-like temperatures which will inevitably drench the person in sweat, this solar powered robot has been created ready to take on the job. With the heart of an Arduino, this device shaves down the grass on a regular basis, rather than only chopping down the material when it gets too long. This helps to save electricity since the mower is only dealing with young and soft plants whose heads are easily lopped off without much effort.

Internally, the robot’s circuitry interfaces with an underground wiring system that defines the cutting zones within the lawn, and proves to be a simple, accurate, and reliable approach to directing the robot where to go. If the device travels under a shaded area, a battery kicks in supplying energy to the engine. When sunlight is available, that same battery accumulates the electricity, storing it for later.

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Arduino SPI Library Gains Transaction Support

August 1, 2014 by Edward Becker 32 Comments

To prevent data corruption when using multiple SPI devices on the same bus, care must be taken to ensure that they are only accessed from within the main loop, or from the interrupt routine, never both. Data corruption can happen when one device is chip selected in the main loop, and then during that transfer an interrupt occurs, chip selecting another device. The original device now gets incorrect data.

For the last several weeks, [Paul] has been working on a new Arduino SPI library, to solve these types of conflicts. In the above scenario, the new library will generate a blocking SPI transaction, thus allowing the first main loop SPI transfer to complete, before attempting the second transfer. This is illustrated in the picture above, the blue trace rising edge is when the interrupt occurred, during the green trace chip select. The best part, it only affects SPI, your other interrupts will still happen on time. No servo jitter!

This is just one of the new library features, check out the link above for the rest. [Paul] sums it up best: “protects your SPI access from other interrupt-based libraries, and guarantees correct setting while you use the SPI bus”.