Solar Cell IV Curve Tracer


This instructable shows how to build a photovoltaic cell curve tracer using Arduino and OPA549S OPAMPS.

This projects shows how to create an IV (Current and Voltage) Tracer that can be used to teach the electrical characteristics of a solar panel.

This project was created as part of an Electrical and Computer Engineering capstone project at The Ohio State University.

Solar Cell IV Curve Tracer – [Link]

USB curve tracer for NPN transistors


Dilshan Jayakody documented his USB port base NPN transistor curve tracer project:

Curve tracer is an electronic test instrument to analyze the characteristics of transistors and other discrete semiconductors. In this post we construct USB base curve tracer to analyze properties of NPN transistors. This curve tracer is build around Microchip’s PIC18F4550 MCU and it use simple Windows based GUI application to plot captured data of a transistor.

USB curve tracer for NPN transistors – [Link]

Basic Switching Voltage Regulator Tutorial


James Lewis @ discuss about switching regulator types and uses.

A switching voltage regulator is one of my favorite circuits. In school, they were the first circuits I built where I understood how transistors worked. In fact, they were the first circuit I saw an inductor being useful! Switching regulators are incredibly efficient when designed properly. Of course, this detail about design is important.

Basic Switching Voltage Regulator Tutorial – [Link]

Arduino Body Thermometer + LCD I2C


This is a body thermometer using a thermistor sensor, Arduino and LCD display.

I’ve decided to provide a funny Arduino concept thermometer in case its the middle of the night, pharmacies are not working, you are not feeling well and you want to check your body temperature. If you have Arduino by your side, this is a life saver!

Arduino Body Thermometer + LCD I2C – [Link]

Simple circuit provides precision ADC interface


Moshe Gerstanhaber @ provides an simple ADC interface using instrumentation amplifier IC.

Real-world measurement requires the extraction of weak signals from noisy sources. High common-mode voltages are often present even in differential measurements. The usual approach to this problem is to use an op amp or an instrumentation amplifier and then perform some type of lowpass-filtering to reduce the background noise level.

Simple circuit provides precision ADC interface – [Link]

AAduino – Arduino Wireless in AA form factor


Johan wanted to shrink his Arduino based ISM radio node to fit in an AA battery compartment so AAduino was born.

The AAduino is an wireless Arduino clone the size of an AA battery with Keystone battery terminals rotated 180° to act as positive and negative terminals. It is powered by an ATMega328p and is fitted with an RFM69C companion. There is room for two DS18B20 temperature sensors and an indicator LED.

AAduino – Arduino Wireless in AA form factor – [Link]

PIC16F628A Programmable Digital Timer


Raj Bhatt shared another project with us. This time is a programmable digital timer with relay switch based on PIC16F628A.

Programmable relays find use in numerous automation applications such as automatic street light control, watering and pump control, HVAC, home automation, power plants automation in industries, etc. This article describes how to build a fully functional, one-channel programmable relay switch using the PIC16F628A microcontroller. It allows you to set both ON and OFF time. The maximum time interval that you can set for on and off operations is 99 hours and 59 minutes. Another interesting feature of this project is it offers cyclic option, which means you can choose to run it in a continuous loop of ON and OFF cycles. The device can be programmed through 4 push switches. The programming menu and device status are displayed on a 16×2 character LCD. The timing resolution of this relay timer is 1 minute. The timer also saves the user inputs to its internal EEPROM so that it can retain these values after any power supply interrupt.

PIC16F628A Programmable Digital Timer – [Link]

Mini Arduino Lux Meter


Here is a nice build of a LUX meter using BH1750 sensor and a Nokia 5110 LCD. The meter is controlled by an Arduino Pro Mini and is powered by a Li-Ion battery. The LCD backlight is controlled according to environment light and there is graphing capability of the measured light intensity.

That’s when I realized that I had an unused BH1750 light meter module laying around, which I bought some time ago but never used it. So I grabbed an Arduino, a Nokia 5110 LCD, wired everything up on a breadboard and had a functioning lux meter within a few hours. To make it a bit more fancy, I added some graphing functionality and made the LCD backlight switch on/off depending on the light level.

Mini Arduino Lux Meter – [Link]

Control ESP8266 over the internet


Here is a basic tutorial on how to control ESP8266 over the internet using two buttons on a browser window. The article goes through Arduino IDE configuration and example code is included.

There are but a few things better than (succesfully) programming and using your Arduino. Surely one of those things is using your ESP8266 as an Arduino with WiFi!

Control ESP8266 over the internet – [Link]

DIY Morning Feed With LED Matrix


Here is a LED matrix able to show useful information such as weather forecast, temperature and stock updates. The matrix is controlled by a Particle Photon board.

You wake up in the morning. You’re groggy. You grab your phone lazily and start browsing. You check the weather, your stocks, your instagram. Before you know it, you’re running late! Do your mornings look like this too? We’ve been there! We wanted to streamline our mornings so we built a morning feed so that we can get all the info while we brush our teeth.

DIY Morning Feed With LED Matrix – [Link]