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14 Feb 2012

pcmofo writes:

I wanted to make an easy and secure way to enter my garage. RFID was the best way to unlock my door, even with my hands full I can unlock the door and push it open! I built a simple circuit with a basic ATMega 168 arduino chip and a ID-20 RFID reader to control an electronic door lock.

The circuit consists of 3 separate parts, a Reader to read RFID tags, a Controller to accept data from the reader and control the output of the RGB LED and the Electric door lock. The door lock is first installed in a door and tested with a 9v battery to ensure correct installation. In most cases you want a Normally Open circuit on the door lock, or Fail Secure. This means the door stays locked when no current passes through it. When 12vDC is passed through the electromagnet in the door lock, a plate in the lock gives way and allows the door to be pushed open freely.

Arduino RFID Door Lock - [Link]

11 Feb 2012

dangerousprototypes.com writes:

Tronixstuff has posted a tutorial explaining how to use the Parallax Ping sensor with Arduino. The Ping is an ultrasonic distance sensor from Parallax which retails or about $30.

This segment is the latest in a series of Arduino tutorials posted by Tronixstuff.

Tutorial: using Ping ultrasonic sensor with Arduino - [Link]

11 Feb 2012

Wade made a tiny Arduino compatible board. It has 8 Digital I/O pins, 4 Analog pins, and an on-board lipo charger.  The ATmega32U4 microcontroller has more memory than the original Arduino. [via]

Digital pins 0-7, Analog 2-5, and a RST, V+, and GND pin are broken out to two rows of pins, maintaining about half the pins in a familiar shape and organization. A JST connector for LiPo batteries like the ones available through SparkFun and Adafruit and an MCP73811/2 charger circuit makes the Demiduino well suited for portable applications. On the back, I’ve also included CR1225 clips for ~3v3 power from easy to find coin cell batteries, and a power switch to save battery life.

Demiduino, another tiny Arduino compatible board - [Link]

11 Feb 2012

Eric built himself a battery monitoring system based on the ATmega328 Development Kit. He drained a 9V battery with 100mA of current and monitored the voltage drop until total depletion. He used this data to estimate how much time is left until depletion – [via]

The 100mA constant load was chosen because my ProtoStack Arduino Clone with LCD draws about 92mA and I wanted to write a sketch to display a battery bar and the approximate hours battery life left. Since all batteries have an internal equivalent series resistance (ESR), it is important to take that into account when only using a battery’s voltage to monitor its state of charge. Since we discharged the battery through a load that is similar to the ProtoStack board with LCD, the ESR of the battery has automatically been accounted for in the voltage measurements.

Monitoring battery voltage to calculate capacity with an Arduino - [Link]

3 Feb 2012

dangerousprototypes.com writes:


Here (machine translation) is a DIY single-layer version of the Arduino Leonardo. The blogger goes into detail on how to build one yourself. Everything is covered from preparing and etching your own DIY board, to fine pitch soldering of the ATmega32u4 IC. Once you have built your board, they show you how to upload a bootloader into the microcontroller.


The Arduino Leonardo is a new platform from the Arduino team that uses the ATmega32U4 uC with built in USB capability. This eliminates the need for the expensive FTDI USB-to-serial ICs and keeps the costs down.

DIY Arduino Leonardo clone - [Link]

3 Feb 2012

If your Arduino project has minimal IO needs, you may want to consider shrinkifying it. This video demonstrates High Low Tech’s method for programming an ATTiny with Arduino code. Maker Randy Sarafan has designed an 8-pin Arduino programming shield to make the task easier. [via]

Shrinkify your Arduino project - [Link]

3 Feb 2012

Don built an Amblight for his home theater PC. He put together this tutorial describing his build of a multichannel Arduino-based Ambilight. He estimates the BOM at $40 (in addition to the Arduino). [via]

The bill of materials include 6+ ShiftBrites (your call, I wouldn’t do less than 6 though), a printed circuit board, wire, and headers. Additionally this will require all of the components needed to get over 0.5 Amps at 5.5-9V DC on to the board to drive the ShiftBrites; this cannot be reasonably done over USB power. My ultimate goal here is to give others some ideas on how to go about this project for less money than it would cost to essentially buy everything in a kit. I went in to this trying to be resourceful and I feel pretty good about how it turned out.

DIY Arduino Ambilight using ShiftBrites - [Link]

2 Feb 2012

kalshagar.wikispaces.com writes:

Goal is to replace this Ikea super cheap timer that works … well, as good as something manual that you paied less than 200 JPY (less than 2 euro). Not precise, sometimes doesn’t ring, or ring just the blink of an eye, so easy to miss…

The new timer will:

  • Have a graphical LCD (bought one one year ago, never used it, needed a pretext, so…)
  • Work on battery (1x 9v battery)
  • Play music when it’s time
  • Use a speaker and amp
  • Possibly use a YMZ294 ?
  • In fact something else but much better…
  • Have an on/off system with a push-button, not a open/close switch In fact a tilt switch
  • No arduino, but a simple atmega 328 (more than sufficient)
  • Keep me busy a few days while allowing me to use some parts I bought long time ago and create a un-reasonable and out of price kitchen timer

Arduino KitchenTimer - [Link]

1 Feb 2012

Jaanus has been working on a subminiature Arduino clone which be believes is THE smallest – [via]

Everybody are making Arduino clones. So I thought I should make THE smallest. I took smallest package atmega88 – qnf28 (5mm x 5mm). Routed smallest possible resonator and as much pads as i could fit on in.

His design provides SPI, UART, one LED and breaks out 4 analog and 1 digital IO pins.

tinyDino – smallest Arduino board - [Link]

1 Feb 2012

ibuildthings.ryanblace.com writes:

Remembering to take a vitamin daily is simple enough. Remember to take a vitamin every three days is nearly impossible (for me). I wanted a solution which will remind me to take the pill and require zero effort. This small project holds two bottles in a fairly nice looking box and flashes red until you take the pill. The act of picking up the bottle (the pill ingestion is assumed) is the entire interface.

Arduino vitamin – pill reminder - [Link]





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