When you are working with electronics or simply building stuff, you probably always end up testing one or several components for their faults or making sure parameters are within specs. Most of those tasks can be done with multimeter. Obviously any multimeter have resistor and capacitance testing modes. Anyway, there are more components that may be tested and using multimeter might require some setup. Baweja_akshay have built pretty universal component tester which is capable of testing most of non power electronics components.
I is capable of testing resistors, capacitors including ESR, BJTs, FETs, MOSFETs, JFETs, Thyristors (SCR, DIAC, TRIAC), IGBTs, diodes. Additionally tester is capable of measuring voltages up to 50V, frequency and even generate signals. Optionally there is an IR code detector. The tester is based on Atmega328 microcontroller which drives all testing logic and displays results on LCD screen. After building first version and seeing what needs to be improved, he plans on building second tester version which is going to be more compact and feature rich.
Wearable electronics is commonly used in many areas. We are not talking about professional stuff like medical devices, but more hobby corner. But who knows where is a limit. Today anyone can assemble wearable projects with cheap building blocks that are mostly based on Arduino. AwesomePCB have shared his instructable on how to build a wearable OLED display covered with leather frame that blends pretty well on fabric.
He used small SSD1306 128×64 OLED display which is connected to small Attiny85 Arduino compatible board. Coin cell battery is enough to power it for quite some time. He paid some attention to details on how display is attached to leather piece and how this piece is snapped to clothes. You can do many fun stuff with the display including a temperature monitoring by attaching thermometer, it simply do rudimentary activity tracker with accelerometer or display current your mood with smileys which can be changed with single button press.
In this project, the user can ask the ball a yes/no based question and the ball will display the answer in form of a sphere which is achieved using persistence of vision. The sphere display has been created by spinning semi-circle shaped LEDs around a central motor shaft. The rotational speed of the LED’s is fast enough such that the human eye perceives a two dimensional image. The software part of the project basically calculates the refresh rates of the LED so it seems like a 2D figure.
There are 19 LEDs consisting of the semi-circle and the entire display area is mapped to a 19 by 90 matrix where each element in the matrix represents a pixel. The device is powered by a ATMEGA128p connected to Led subsystem and the mic circuit. Whenever the Atmega detects an end of the question, the sphere displays a randomly generated yes/no as an answer to the question. Another feature about our device is that the LED array can generate quite bright light, people can see the display without having to turn off the light. A project which can be made to amuse people in your free time and also to learn the concept of persistence of vision.
This project is for the people who faces difficulty in waking up early in the morning or have the habit of snoozing the alarm. In short, this alarm clock runs away from the user as he tries to snooze his alarm. The whole unit is mounted on a chassis with caterpillar-style wheels driven by two small DC motors. The runaway feature is implemented using a proximity sensor which is placed near the snooze button. It has all the features of a “regular” alarm clock: settable time and alarm, snooze, and alarm on/off.
The project is divided into four levels namely the clock feature with display. The alarm feature motion control and proximity detection. The alarm tone is generated using a 555 timer while a real timer kernel is implemented on the Atmega MCU to run each of these tasks independently and simultaneously on the microcontroller. The display is built out of seven segment LED’s running on the principle of persistence of vision. The accuracy of the clock is pretty good, and the speed of the bot can be raised up to 10m/s. The source code of the project is available on the project website along with the necessary libraries.