12V Lead Acid Battery Monitor is a simple project which tells you the voltage of your Lead acid battery visually with the help of 10 LED’s. This project is based on the popular LM3914 IC from Texas Instruments.
The LM3914 senses the voltage level at the input pin and drives the 10 light emitting diodes based on the voltage detected on input connector. Circuit works on same battery, doesnt not require separate supply input. Jumper is used to select the DOT mode or bar graph mode.
12V Lead Acid Battery Voltage Monitor – [Link]
by TheSpodShed @ instructables.com:
This is a magic box which will let you monitor the power consumption of your house from anywhere on the Internet! It measures both true power (Watts) and apparent (VA) power, it keeps a running total of electricity units used, and measures mains frequency as a bonus.
The project uses a Particle Core(*) module – a little board with an ARM microprocessor and a Wi-Fi interface – to do all the hard work. To build it, you’ll need to be able to solder and follow a simple circuit diagram. At UK prices, total parts cost should be no more than £50.
Internet connected home energy monitor – [Link]
by SwitchDocLabs @ instructables.com:
WeatherPi is a solar powered Raspberry Pi WiFi connected weather station designed for Makers by SwitchDoc Labs. This is a great system to build and tinker with. All of it is modifiable and all source code is included.
WeatherPi – Solar Powered Raspberry Pi weather station – [Link]
Dilshan Jayakody has published a new project, a DC millivolt source:
DC millivolt sources are often used for thermocouple simulations, DMM, ADC and analog circuit calibrations and fault findings, etc. Most of the DC millivolt circuits are based on expensive (and sometimes hard to find) operation amplifier like OP7, LT1077, etc. In this article we introduce low cost DC millivolt source based on commonly available LM308 precision operational amplifier, ICL8069 low voltage reference and 78L05 voltage regulator ICs. This millivolt source is design to obtain 200mV – 700mV DC output with 100Ω impedance. At the time of writing we spend Rs.800.00 (LKR) to complete this project.
Low cost DC millivolt source – [Link]
0-10V Volt monitor project has been designed around LM3914 IC, It is an easy and less expensive project which instantly visualizes voltage level. The project is based on the popular LM3194 IC from Texas instruments. Handy 0-10V DC Voltmeter can be used as a voltage tester.
The LM3914 senses the voltage level at the input pin and drives the 10 light emitting diodes based on the voltage detected on input connector. Circuit works on 12V DC. J1 Jumper is used to select the DOT mode or bar graph mode.
0-10V Voltage Monitor – [Link]
This is a variable range LED bar graph voltmeter project. It is a simple and less expensive project that displays voltage of a given source with the help of 10 LEDs. The project is based on the famous LM3914 IC from Texas instruments.
Variable Range LED Voltmeter – [Link]
by kkingsbury @ instructables.com:
Back in late February I saw this post on the Raspberry Pi site.
They had created Raspberry Pi Weather Stations for Schools. I totally wanted one! But at that time (and I believe still as of writing this) they are not publicly available (you need to be in a select group of testers). Well, I wanted on and I didn’t feel like shelling out hundreds of dollars for an existing 3rd party system.
So, like a good Instructable user, I decided to make my own!!!
Complete DIY Raspberry Pi Weather Station with Software – [Link]
by PiJuice @ instructables.com:
Spurred on by the completion of my two previous projects, the Compact Camera and Portable Games Console, I wanted to find a new challenge. The natural progression was an outdoor remote system…
I wanted to build a Raspberry Pi weather station that was able to sustain itself off grid and send me the results through a wireless connection, from anywhere! This project really has had its challenges, but luckily powering the Raspberry Pi is one of the main challenges that has been made easy by using the PiJuice as a power supply with it’s added solar support.
Raspberry Pi Solar Weather Station – [Link]
The circuit shown is a microcontroller based Energy Meter that uses MCP3905A as its main component, which is an energy-metering ICs that supplies average power information through a pulse with direct drive for mechanical counter. It includes a higher-frequency output supplying instantaneous power information for calibration while conforming the IEC 62053 International Metering Standard Specification. The energy meter provides exceptional accuracy in measuring the amount of energy consumed by an electrically powered device. It can significantly read immediate power usage, which may be used to perceive future energy consumption.
Microchip’s MCP3905A energy meter reference design is a standalone, single-phase residential meter for active energy meter design. In addition, MCP3906A can be used in the project. For calibrating the frequency output, a voltage divider calibration circuit was optimized. Each meter must be calibrated using the voltage divider circuit going into Channel 1 of the MCP3905A/06A. The MCP3905A/06A has appropriate bypass capacitors on VDD coming from the DC power supply circuitry and has its input logic pins connected to user-selectable jumpers, with the exception of the HPF pin. For this system, the HPF is turned ON with this pin connected to VDD. Moreover, the DC power supply is created from a half-wave Zener diode limited AC signal feeding a 7805 +5V regulator. The Zener diode D2 however, limits the peak voltage to 15V while the optical isolator is included in the reference design as an additional level of protection for other circuitry.
Energy meter system had been widely used to measure the energy consumption to residents, industries and businesses benefiting the power usage. It is typically calibrated in billing units such as kilowatt-hour and periodic readings of electric meters, which establishes billing cycles and energy used.
Energy Meter based on MCU – [Link]
While trying to create a circuit that detects whether water is flowing through a pipe by measuring the vibration with a piezoelectric sensor, just to see what happens I taped the sensor around my finger and – to my surprise – got values that were a very noise-free representation of my heart rate!
Measuring Heart Rate With A Piezo – [Link]