Arduino Projects of note

• Arduino temperature controlled PC Fan.

• Tutorial: Arduino and the I2C bus – Part One

• Arduino Mini Pro + RTC DS3231 + I²C LCD backpack / I²C scanner + LCD clock demo code: [1]

• cheap good rtc http://www.dx.com/p/ds3231-high-precision-real-time-clock-module-blue-3-3-5-5v-222910#.VGg-R_nF98E

RTC

I have some zs-042 RTC , it has a DS3231 RTC and what looks like an ATmega32 on it.

https://edwardmallon.wordpress.com/2014/05/21/using-a-cheap-3-ds3231-rtc-at24c32-eeprom-from-ebay/

http://misclab.umeoce.maine.edu/boss/Arduino/bensguides/DS3231_Arduino_Clock_Instructions.pdf <- this worked.

used this: https://github.com/JChristensen/DS3232RTC ( worked )

also on board "AT24C32 EEPROM" https://breadboardtronics.wordpress.com/2013/08/27/at24c32-eeprom-and-arduino/ ... a place to store data.

LCD

Liquid Crystal Display

Some notes:

• http://tronixstuff.com/2011/01/08/tutorial-arduino-and-monochrome-lcds/

Voltage Comparator Based Sensor

Picked up a soil moisture sensor from Deal Extreme ad 2.23 USD$

http://www.dx.com/p/soil-humidity-moisture-detection-sensor-module-blue-black-white-200142

It's based on a lm393 voltage comaparator. Many variation exist, for things like sound and light aswell.

This is an analog to digital sensor NOT a 1 wire sensor, so it soaks up an analog pin.

Resources:

Arduino Code example:
http://arduino-info.wikispaces.com/Brick-LightSensor-Analog-Digital

LM 393 Datasheet:
http://www.ti.com.cn/cn/lit/ds/symlink/lm293-n.pdf

From analog to digital

So you got a bunch of cheap sensors, but they are all voltage oriented, like lm 939 and tmp36 and lm35, but you want to hook up a pile of them. wouldn't it be great if you could "convert" the voltage changing sensors to 1 wire or I2C ?

By using a buss ( like I2C ) you can attach many sensors to a single pair of arduino digital pins.

You can! Some notes so far below.

Analog to I2C

http://www.ti.com/lit/ds/symlink/ads1000-q1.pdf

I2C What resistor

http://electronics.stackexchange.com/questions/1849/is-there-a-correct-resistance-value-for-i2c-pull-up-resistors

level shifting : http://playground.arduino.cc/Main/I2CBi-directionalLevelShifter

one I2C device many outputs

• pca9685 ic