Search Results for : LM317
![Programmable Home Security Alarm System Programmable Home Security Alarm System](https://www.electronics-lab.com/wp-content/uploads/2015/03/autoalarm_final_board.jpg)
Programmable Home Security Alarm System
Introduction In this project we design low cost high performance programmable home security system and there is no need to contact a company like Safemart home security for setup. This system uses a few LDR's as input sensors. When above sensor(s) get triggered system may dial...
Continue Reading![PIR Motion Sensor PIR Motion Sensor](https://www.electronics-lab.com/wp-content/uploads/2015/03/photo_227.jpg)
PIR Motion Sensor
Introduction The objective of this project is to use inexpensive PIR sensor to detect if a human has moved. To build this project I use a PIC18F25K20 microcontroller to detect if the sensor had change state and it will emit a sound from the speaker or piezo, the MCU also detect the...
Continue Reading![Dual Adjustable Power Supply Dual Adjustable Power Supply](https://www.electronics-lab.com/wp-content/uploads/2015/03/004_PIC.png)
Dual Adjustable Power Supply
This project is a solution to power up most of devices or projects requiring dual (+/-) adjustable power supply. Description The circuit is based on LM317 positive and LM337 negative voltage regulators. LM317 series of adjustable 3 terminal regulator is capable of supplying in...
Continue Reading![MCU Controlled Spot Welder MCU Controlled Spot Welder](https://www.electronics-lab.com/wp-content/uploads/2015/03/3d_pcb_1_th.png)
MCU Controlled Spot Welder
This project is a controller for a dual pulse spot welder that has some nice features that are controlled using a LCD interface. Description I always wanted a spot welder, so I decided to built one. I wanted to build a capacitance discharge one but I couldnt afford for the...
Continue Reading![Lead Acid Battery Charger #2 Lead Acid Battery Charger #2](https://www.electronics-lab.com/wp-content/uploads/2015/03/Schematic20.gif)
Lead Acid Battery Charger #2
Description The above pictured schematic diagram is just a standard constant current model with a added current limiter, consisting of Q1, R1, and R4. The moment too much current is flowing biases Q1 and drops the output voltage. The output voltage is: 1.2 x (P1+R2+R3)/R3 volt....
Continue Reading![Simple 78xx Current Booster Simple 78xx Current Booster](https://www.electronics-lab.com/wp-content/uploads/2015/03/Schematic18.gif)
Simple 78xx Current Booster
Description Voltage regulators such as the LM78xx, and LM317 series (and others) sometimes need to provide a little bit more current then they actually can handle. If that is the case, this little circuit can help out. A power transistor such as the 2N3772 or similar can be used...
Continue Reading![LED UV exposure box LED UV exposure box](https://www.electronics-lab.com/wp-content/uploads/2015/03/UVbox12.jpg)
LED UV exposure box
Introduction I have been using the toner transfer method for about 9 years with great results. Occasionally I would need a board with finer traces and I would use UV method. My exposure setup allowed only a single sided board to be made and it was composed of a 30cm UV tube,...
Continue Reading![MCU controlled Bluetooth automation with infrared sensor MCU controlled Bluetooth automation with infrared sensor](https://www.electronics-lab.com/wp-content/uploads/2015/03/image_15.jpg)
MCU controlled Bluetooth automation with infrared sensor
The microcontroller used is 0822 zilog encore! 8k series (soic,28pin) as shown on the figure. Is a programmable microcontroller, the functions used are the GPIO and the UART of the chip. GPIO is used on led indicators, and the UART is used for giving and reading AT COMMANDS to control...
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