Electronics-Lab.com Blog

Nove Bit from Nick Hardeman on Vimeo.

Nove Bit is an interactive 3 x 3 matrix that allows users to record sequences of light and save them as 9 bit memories. Nove Bit addresses human to computer interaction by allowing the user to physically input the memory as 9 bits, as opposed to the traditional 8 bit computer memory. Nove Bit also touches on the notion of a personal memory by recording a users

thoughts in time and replaying them as a pattern of lights. The visual memories are stored as 9 bits, represented by a corresponding button. Compared to 8 bits, 9 bits also allows for a visually even distribution of the memory as a square. The “Nove” which means nine in Italian, also references the Arduino Duemilnove, one of the two micro-controllers that control the unit.

Nove Bit - [Link] 

An optocoupler volume control! What makes this one neat is that optocouplers are used in the circuit. The optocoupler consists of an LED and Light Dependent Resistor (photocell) in a sealed unit. So by varying the intensity of the LED, you can adjust volume. Also, the volume control has no “contact points” in the signal path. So forget about those scratchy potentiometers and get rid of the contact cleaner. The project as shown is 2 channels, but one could easily scale this one up to control multiple channels which could be useful for a DIY home theater.

DIY Lightspeed Passive Attenuator - [Link]

Ever wanted to build a highly dangerous, inefficient, yet awesomely retro piece of electronics? Well, I have. That’s pretty much what a tube amp is. Vacuum tubes are old electronic components that act like transistors, controlling a lot of current with a little current. You usually hear about tubes being used in guitar amplifiers, because they distort in a way that suits guitar playing. However, tubes can also be used to amplify a stereo signal from another audio source such as a CD or MP3 player. Tube amps, unfortunately, aren’t the most practical things in the world; they consume a great deal of power, get very hot, and are big. That being said, they look damn cool, and some people seem to think they sound pretty nice too.  Kit is also available.

Building A Stereo Tube Amp - [Link]

Even though cooking is an elegant art form, the at-home chef often has a number of fancy gadgets. From counter top grills to USB coolers, high end electronics have made themselves available in most aspects of modern food preparation and enjoyment. In keeping with our DIY spirit, and with Father’s Day and July 4th grilling right around the corner, we decided to build a DIY Digital Meat Thermometer using a temperature sensor, an LCD, and a microcontroller. To our delight, getting this project to work well required some interesting bits of engineering including advanced signal processing. In this video tutorial, we outline the process for building the DIY Digital Meat Thermometer. In order to speed up the measured reading, we estimate what the transfer function of the system is and use a predictive filter to “guess” what the actual temperature is at the tip of our probe. The concepts, and the some of the intuition behind it, are presented in our video tutorial. The meat thermometer can be used with a computer to give a live temperature graph, or be used with just the LCD. Whether it’s a fathers day gift, or just a fun weekend project, this little gadget is sure to draw some attention at the next family cookout.

 DIY Digital Meat Thermometer with Predictive Filter - [Link]

Here is a cool java applet written to help find valid values for 5% and 10% tolerance resistors. Quick clicks to common values and a clickable table of standard values in included. The tool even shows you the resistor code to make ordering parts easier.

Online Resistor Color Code Tool - [Link]

Motors are everywhere! From robots to remote-controlled cars, any DIY hobbyist will very quickly find themselves trying to control a motor with a microcontroller. Luckily, simple control of a brushed DC motor is easy, and only requires a few components. Have you ever tried spinning a motor with the contacts connected together? Or seen sparks as you connect and disconnect your motor? What consequences do those things have on how you control the motor and protect your other circuitry? There are instructions out there that allow you to build a complicated motor controller that might work, however in this video tutorial we take a step back and go over some of the very basic things you need to think about when using motors, because so much is dependent on understanding the details of your specific situation. From stall current, to back-EMF, we present 9 small experiments you should try to get a better sense of how the motor is going to behave in your circuit. The tutorial also goes over how to connect a simple motor to a microcontroller, and turn it on and off using a 2N7000 n-channel MOSFET and a few other parts. The topic of power electronics goes much, much deeper. Often times, it is necessary to consider power dissipation, switching frequencies, gate capacitance, and when trying to drive a motor in both directions, an H-bridge is required. However, we have to start somewhere, and there is nowhere better to start than with experimentation!

Using motors with microcontrollers - [Link]

After finishing a project you may need to add it to an enclosure and drill holes to make external connections or install any control buttons and screens. This proccess can be difficult without any special tools and the result may not look as expected. If you like a profesional result FrontPanelExpert.com offers a complete solution to build your own custom front panel in 3 easy steps. You download Centina CAD free software and install it on your pc. Design front panel layout, calculate cost and finally submit your design for proccessing. You are able to choose front panel material from a range of common ones, like aluminum and plastic and order from prototype to mass production.

Illuminato board project – it’s an Arduino / Freeduino board that has 42 digital IO’s and 64k code space. All of the schematics and files are over here.

Illuminato board project - [Link]

We live in the information age. Your phone knows where you like to eat, computer programs know what movies you like better than you do, and going to a party can mean going in this life, or a Second Life. So why is your message of love still stuck in the 16th century? These days it takes more than a sonnet to melt a girl’s heart. This video tutorial shows step-by-step how to make a Valentine’s Day card for the digital age. The NerdKits team shows how to make an LED Heart Valentine’s card powered by a microcontroller. The heart features an LCD screen for a personalized message, and 20 LEDs around the perimeter that can be programmed to show any pattern. The code provided contains a “twinkle” function that randomizes the process to provide a true star-like twinkle.

DIY LED Heart - [Link]

What do you do if you have a spare LCD module with backlight, a weird 16 button keyboard, and a PIC16F877A microcontroller gathering dust? A monster Martian Clock immediately springs to mind.

You are probably thinking “There are hundreds of PIC clocks on the Net – do we need yet another one?

This clock is quite different than all other PIC clocks I’ve seen in this that it has multiple timers that can work with different speeds (for example, you can have one showing your local time, another working on Mars day time, another showing the moon phase, etc.)

Mars Clock – PIC-microcontroller-based clock - [Link]