by praveen @ circuitstoday.com:
Digital code lock or digital combination lock are a type of digital locks where a combination of digits/characters or both are used for unlocking the lock. This article is about a simple digital code lock using arduino. Here the code consists of a combination of digits from 1 to 6. There are separate keys for locking and unlocking the system. The system can be unlocked by pressing the unlock button after entering the correct combination of digits. A hex key pad is used as the input device. Only the first two rows of key (1, 2, 3, A, 4, 5, 6, B) are used in this project. A is used for locking the system and B is used for unlocking the system. Read this article Interfacing hex keypad to arduino for knowing more about hex keypad and its interfacing to the arduino. The circuit diagram of the digital code lock using arduino is shown in the figure below.
Simple digital code lock using arduino - [Link]
Once all the components and headers were soldered in, I attached my Arduino and configured it as an ISP. I then burned the bootloader for an Arduino Uno.
I then connected my FTDI programmer and uploaded the blink sketch.Success!
Wow, that LED is super bright! It’s actually blinding and kind of hard to look at. With that, I swapped out the resistor for a 1K one in order to bring the brightness down.
Knowing that the Atmega worked, it was time to solder in the rest of the components, except for the display. Again, I don’t want to come this far and then waste a $15 LCD.
LCD clock version 2 - [Link]
EGYDuino is a DIY Arduino clone made on a single sided PCB board. It’s simple and cheap to build using home PCB fabrication methods and it’s 100% compatible with Arduino.
The features of this board are:
– It’s using ATmega8 as interface IC
– Has USB connection to PC
– Standard RESET button
– 100% compatible Arduino PINs
– 5V regulator
– 3.3V output
– compatible size and design
– All component are TH (through hole) parts
– USB or DC power switch
– LED for PIN13 with Jumper
– LED for power
– ICSP PINs
– easy to build
– ATmega8,168,328 core for arduinoNG
– standard DC power jack
EGYDuino – Arduino compatible board - [Link]
This instructable describes a project named Duinocade, a mini pong arcade game based on the open source handheld Gamebunio. [via]
Duinocade is a very small arcade cabinet (14cm / 5,5inch height). The software and parts of the circuit diagram based on the open source handheld Gamebunio, which based on the famous Arduino platform. The Gamebuino and also our Duinocade uses the knowns Nokia 5110 lcd as screen. At the moment the Gamedunio is an Indiegogo campain and wil be official available in July. But some games for example Pong are finished by the Gamebunio community until now… [...]
The electronic is realized on a breadboard. In the future we will create a pcb layout and perhaps also a DIY kit. In contrast to the Gamebuino we don’t have an lithium battery and an USB port. The Duinocade is powered by an external (wall) power supply. The electronic fits in the slot for the iPhone. We don’t have to made mechanical modifications of the case exept one additional hole for the power socket. We’ve mounted only an 3,3V power supply, the ATMEGA328 microcontroller, SD card socket and the Nokia LCD on this breadboard.
Mini Pong arcade using Arduino - [Link]
Interfacing hex keypad to arduino @ circuitstoday.com
This article is about how to interface a hex keypad to arduino. Hex keypad is a very important component in embedded systems and the typical applications are code locks, calculators, automation systems or simply any thing that requires a character or numeric input. This project will display the pressed key in the serial monitor window of the arduino IDE. The same project can be modified to display the pressed key on 7-segment LED display or an LCD display. Before going into the details, have a look at the hex keypad.
Interfacing hex keypad to arduino - [Link]
by Tony Keith:
You have a project that accepts commands using a 16 button keypad and want to perform validation on the commands as each character is typed. But how? Use state machine logic / programming to solve the problem. If you aren’t familiar with or haven’t used state machine logic in programming, it is the easiest way to to break complex problems into manageable states and state transitions especially for handling serial input. One of the easiest ways to implement a state machine is to use a switch statement. In my opinion it is the only way to implement serial input commands.
Keypad Input Validation using State Machine Programming - [Link]
praveen @ circuitstoday.com build a Digital thermometer using arduino and LM35
This article is about a simple three digit digital thermometer using arduino. Range of this thermometer is from 0°C to 99.9°C. There is also a provision for displaying the temperature in °F scale. Three terminal analog temperature sensor LM35 is used as the sensor here. LM35 can measure temperatures between -55°C to +155°C. The supply voltage range is from 4V to 30V DC and the current drain is 60uA. The LM35 is available in TO-92 package and it is very easy to use. The output voltage of the arduino increases 10mV per °C rise in temperature. That means if 25 °C is the temperature, then output voltage of the sensor will be 250mV. Circuit diagram of the digital thermometer using arduino and LM35 is shown in the figure below.
Digital thermometer using arduino - [Link]
ICStation @ instructables.com writes:
ICStation team introduce you how to DIY this temperature & humidity & smoke alarm system based on ICStation Mega 2560 compatible with Arduino.The working voltage of this system is DC5V.It can measure the current temperature, humidity and smoke. It can display real-time data by the 1602 LCD and can realize the sound and light alarm when in the dangerous temperature and humidity. It is a simply and easily to operate monitoring alarm system about temperature humidity and smoke.
DIY Temperature & Humidity & Smoke Detector - [Link]
singingshark @ instructables.com writes:
Welcome! For our Environmental Capstone class (senior thesis) for St. Olaf College we built a monitor that would effectively monitor how much water a shower uses. For our project we made four different monitors using the same process. This instructable is written as if you were to make a single water monitor. [...]
Shower Monitor Arduino with LCD display - [Link]
praveen @ circuitstoday.com posted a project on a Temperature logger using Arduino:
This project is about a simple USB temperature logging system using arduino uno and the serial monitor function in the arduino IDE. The system monitors the temperature every 2 seconds and shows it on the arduino serial monitor. The temperature is shown in °Celsius and °Fahrenheit. The system is interfaced to the PC through the USB port. LM35 is used as the temperature sensor.
LM35 is three terminal linear temperature sensor from National semiconductors. It can measure temperature from-55c to +150C. The voltage output of the LM35 increases 10mV per degree Celsius rise in temperature. LM35 can be operated from a 5V supply and the stand by current is less than 60uA. The pin out of LM35 is shown in the figure below.
Temperature logger using Arduino - [Link]