It’s just as simple as this, the LDR reacts when it gets less light than the laser-dot in the center of it. Which is when something comes in the lasers way. So then you know when something passes the invisible line between the laser and the LDR.

Lets begin with what components you need:

1x Laser Emitter/Pen
1x LDR
1x Resistor 10k (doesn’t have to be 10k ohms)
1x Piezo Buzzer (you can use a LED or anything else you want)

And of course a Arduino board of your choice, and some wires.

Lets wire it all up like this:

Things to notice, buzzer is grounded and the + wire is on the digital 10. Laser is just ground and +5v to make it light constantly. The LDR is in a voltage divider with a resistor, we take out the readings in the middle where the yellow wire is, and it’s attached to the analog 0.

A picture of the LDR.¨

When all this is wired up, just put this code and run it.

And yes! A very nice shield for use with the pico, Pico Protoshield Kit!
Of course the small breadboard and the pico arduino is sold separately!

Netduino is an open source electronics platform using the .NET Micro Framework.

Featuring a 32-bit microcontroller and a rich development environment.

Suitable for engineers and hobbyists alike.

Netduino is an open source electronics platform using the .NET Micro Framework.
Featuring a 32-bit microcontroller and a rich development environment.
Suitable for engineers and hobbyists alike.

Specifications are:

Atmel 32-bit microcontroller
Speed: 48MHz, ARM7
Code Storage: 128 KB
RAM: 60 KB

all 20 digital and analog pins: GPIO
digital pins 0-1: UART 1 RX, TX
digital pins 2-3: UART 2 RX, TX
digital pins 5-6: PWM, PWM
digital pins 7-8: UART 2 RTS, CTS
digital pins 9-10: PWM, PWM
digital pins 11-13: SPI MOSI, MISO, SPCK
analog pins 4-5: I2C SDA, SCL

And for only 34,95 USD it’s very interesting

Due to a user one the forums asking me to add some keys I decided to make it a release.
And add some more features!

Current & new Features:

NEW, F Key, +, -, Scroll Lock, Num Lock, Space, Print Screen
NEW,  More delays, 5 to 60 minutes!
BUG, Customs keys fixed! 0.4 to 0.41

Backspace & Arrows up down etc. Also Alt + F4.
Option menu.
Click sound (can be turned on/off)
You can now hide it from taskbar.
Many different intervals for buttons to be clicked.
Custom buttons, lets you write you’re own button combination to be pressed.
Default buttons, like enter, page up etc.
Minimize to tray, hides it while running if you want.
Also logs how many key presses made.
Delayed start.
F1-F12 and more predefined buttons.

Of course it’s freeware, and you might download and share it as much as you want.

Download KeyPresser 0.41

I’ve just recently discovered this awesome game. It’s a combination of Garrysmod/Cortex Command/Dwarf Fortress/Clonk, and Blockland.

To keep it short, you mine blocks to get different materials or building blocks. Then you can farm, hunt, craft etc. That is if you bought the game and get to test out the indev version. If you haven’t bought it, you can try out the survival mode. Or the sandbox single-player or multi-player where it’s all about building and digging. Which is also very fun, especially in multi-player mode. Read more about the game here.

To keep it short, you need to give it a try!

A few screens:

Overview of my farm, on the walls are torches to light it up when night time comes sneaking.

The “inventory” where you can see my armor, and all my slots for weapons etc.

And a happy new year!

I got the RF sender & receiver from Sparkfun today!

RF Link 2400bps Receiver – 315MHz
RF Link Transmitter – 315MHz

Also a 20×4 serial LCD, gonna be useful for advanced applications. Anyhow, if you got the RF kit, and was like me wondering how to get it working. I found this nice guide at LMR.

Now it’s just to find a nice way to use the RF links, it’s only one-way communication, but it’s gonna be awesome to use it as a remote for one of my robots!

http://stigern.net/forum/index.php

Botty 2:

This is the most advanced robot I’ve built, but it’s not nearly finished.

It’s current task is to drive straight forward until it senses a object with it’s IR-sensor, then drive away from it until it’s cleared, and continue in that direction. Really simple

It uses a Sharp-IR sensor, mounted ontop of a servo, so it scans the horizon while driving forward. The sonar in the picture isn’t in use, since I actually like the IR sensor better.

BewBit:

Simple and yet fun to make arduino bot. Just follows the strongest light source. Using two LDRs, a modified pico and 1xAA and 2xAA battery packs, to give out 4,5 volts. Just enough to power theSN754410 and motors. But it gets around. It also includes a low-voltage alarm, which beeps when the voltage goes low.

Had a little accident, it drove over a carpet, or it came about 30cm into it and some funny gear-whining noise came A lot of hair in the gearbox, had to take it apart and clean it.

Future plans:

* Crash sensor, a small micro switch in front.
* Speaker, plays sound according to light source
* Better code

I just want to write a few words for those new to Arduinos, or those looking for tutorials, guides etc. If you haven’t got a Arduino board yet, you can get one from several places, I’ll list some of my favorite shops. And of course you also need the Arduino Software!

Sparkfun
Seeedstduio
Adafruit

Or, Modified Electronics for the great Pico! (not recommended for beginners, you’ll be better of with a normal board).

What you are looking for is the Arduino Duemilanove, the USB board. Which will suit most your needs. It’s very easy to use, and wires can be plugged right into it. Later on you might want a Boarduino or maybe a Pico as mentioned above, they are great for using in combination with breadboards! Alternatively you can get the Starter kit, almost all shops got these. Sparkfun got a nice kit, which is worth a look.

If you should want more I/Os, or just more space for code the Arduino Mega is a great choice! Or the Sanguino!

Parts!

You will always need parts, resistors, leds, breadboards, wires etc. I’ll list up a few shops that I use the most.

Futurlec

Lots of cheap basic parts! recommend the resistor packs, and they also got cheap breadboards. And all of the shops mentioned above stock parts too. For jumper-wires I recommend these at seeedstudio. Futurlec also got some nice jumper-kits. For extra small breadboards these at Seeedstudio are very nice!

Pololu

Great site for robotics, motors, gearboxes etc. They also got a nice tracked chassis. They got a lot great products, sensors, motor controllers, etc.

Tutorials/Guides/etc

1. The basic guide, from sparkfun. You should start with this!

2. The Complete Beginners Guide to The Arduino

3. Adafruit’s Arduino Tutorials

4. Arduino.cc`s Tutorials

5. Arduino.cc Reference! Not tutorials, but handy!

Also the Libaries page at Arduino.cc is great! I’m sure you’ll find something to use in several projects!

Well, thats all I’ll write for now. I’m sure I left out alot, and will update this post when I find something new to add

PS. If you got any questions etc, please take it in my forums post here.