A detailed instructions of how to design a cheap plant watering sensor from LuckyResistor:
I have a couple of plants in flowerpots and this plants not only like some light, they also need water from time to time. Watering this plants is something I often forget, with sad results. There are ready made solutions for this, but I have some objections with all of them. To be clear: There are really smart products out there – it is absolutely nothing wrong with them. It is just as I like to build my own fan controller, I like to build my own plant watering sensor in my very own fashion.
Vadim has posted a tutorial on how to use internal RTC of Stellaris and Tiva Launchpad boards in Energia IDE:
For those of you who still have one of those old Stellaris Launchpads, I’m going to show how to utilize one of its most useful features – real time clock – in a simple way. Actually, the Hibernation module is the same in the new Tiva Launchpad, so it’s supposed to work there as well.
A tutorial on making an LM386 audio amplifier circuit from Afrotechmods:
A tutorial on how to use the popular LM386 class AB audio amplifier IC to build a simple mono 1 watt audio amplifier. It costs less than $3 in parts! There is also a brief discussion of how to use high pass filters to prevent op-amp oscillation and subsequent noise.
BME280 is a fully integrated environmental unit from Bosch that combines sensors for pressure, humidity, and temperature in a tiny 8-pin metal-lid LGA package of size 2.5 x 2.5 x 0.93 mm³. Because of its compact size, ease of use (BME280 supports standard I2C and SPI interfaces), and availability of supporting open-source Arduino libraries, BME280 is very popular among weather enthusiasts. This project describes how to read barometric pressure, relative humidity, and temperature measurements from BME280 using chipKIT Uno32 to make a standalone weather station. The sensor readings are acquired over an I2C bus and are displayed on a Nokia 5110 LCD display.
A how-to on using the BMP180 barometric sensor with the Arduino from Random Nerd Tutorials:
The BMP180 barometric sensor (model GY-68) is the one in the following figure (front and back view). It is a very small module with 1mm x 1.1mm (0.039in x 0.043in).
It measures the absolute pressure of the air around it. It has a measuring range from 300 to 1100hPa with an accuracy down to 0.02 hPa. It can also measure altitude and temperature.
The BMP180 barometric sensor communicates via I2C interface. This means that it communicates with the Arduino using just 2 pins.
Playing with RFID and NFC is definitely fun, and they are everywhere! For a research project I’m exploring different RFID tags and solutions. I several types around for a long time, but never found the time to actually work on it, so last nightI thought I give it a try, and I have it working with GNU ARM and Eclipse, powered by the NXP FRDM-K64F board