This project reads the AC line frequency and displays on a LCD. The 120V AC is first converted to 12V AC using a step-down transformer. With the help of a BJT, the output Sine wave is further converted to 5V square pulses which is fed to TOCKI pin of PIC16F628A. The Timer0 module is used as an 8-bit counter. The counter counts the number of pulses arrived at TOCKI port in 1 sec, which, in fact, is frequency of manis AC, and displays it on a LCD.
Timer0 Counting AC Line Frequency - [Link]
Lithium Polymer Batteries are a very common source of power today. Many electronics gadgets have one inside, and they have some reasonable features. I’ve bought great batteries, with different sizes and capacities for my electronics projects. So long I’m using this batteries, coming the problem: charge them.
USB Single Cell LiPoly Charger - [Link]
This project I made for my little daughter. It is 24 channel light illumination. The schematic is very simple 24 LEDs, 1 MCU and some additional components. The main principle is dynamic indication, which is usually implemented for control of 7-segment digital indicators. Here is the same, as for indicators are used traditional 5-mm LEDs.
LED effects - [Link]
A few years ago I built a keyless entry system for my shop using a keypad, now it is time to update it to use an RFID key-fob. My homemade door actuator was made from parts out of an old VCR. The electronics controlling the system consist of a few components, a NE555IC (timer), a small NPN transistor, and a double poll double throw relay.
DIY RFID Keyless Entry System - [Link]
One of the most common way to interface a microcontroler to a computer used to be serial port. But right now, serial port have been replaced with USB on most computers. A common way to fix this issue is to use a USB to TTL converter or a USB to RS232 converter + MAX232. That’s fine but :
Really cheap USB to TTL on Atmega - [Link]
Instructables user AaronX621 writes:
This will show you how to replace the internal battery on your Sonicare Elite 7300. After having my 2nd one die on me within 3 yrs I figured out how to rip it apart and fix it.
How-To: Replace your electric toothbrush battery – [Link]
Nyle Steiner of sparkbangbuzz built a Simple Homemade T.E.A. Laser using some pieces of scrap aluminum and a moderately high voltage power supply. He writes: [via]
I used to tell people “There is no such thing a true home made laser. There is always a requirement for exotic parts that can only be obtained from a laser manufacturer, and – or there is the requirement to perform exotic high vacuum, glass blowing and gas mixing processes. This would defeat much of the satisfaction of building your own laser.” When I read about TEA lasers recently though, that all changed. Here is a laser that is built from aluminum foil, a dielectric and some pieces of aluminum. It is amazing to think of a laser project where a simple 4 to 6 KV DC power supply is the most elaborate component.
DIY ultraviolet laser made from scrap aluminum - [Link]
A PIC16F628A based digital thermometer reads temperature from a Ds1820 sensor and displays on a multiplexed 4-digit Seven Segment Display. The temperature is displayed in both Fahrenheit and Centigrade units one after the other. PIC programming is done on mikroC, and the temperature resolution is 1 in F and C scales. The range of temperature measurement is -55 to 125 C.
PIC16F628A + DS1820 Thermometer - [Link]