These are the RFID readers I used. http://www.parallax.com/product/32390
Arduino RFID Card Door Lock System - [Link]
Rechargeable batteries save us a lot of money but take a lot of time. What if you could recharge a battery in seconds instead of hours?
Rechargeable batteries save us a lot of money these days but for the savings, we give up some of our time, waiting for them to recharge. What if though. What if there was a rechargeable battery that took seconds to recharge instead of hours? That is exactly what I’ve invented and I need your help to bring this to the masses and show the world that we no longer need to waste hours of or lives waiting for a battery to charge.
With the leaps and bounds being made today with capacitors, they’ve gone from being able to store a tiny potential of energy to now, being able to store enough energy to be considered a power source. These high Farad capacitors are known as super capacitors and aside from providing electricity for an extended period of time, they can also be charged very quickly. Recently, there’s been another development, combining the technology of super capacitors with lithium ion batteries. The usually downside to super capacitors from batteries is that they don’t provide electricity for nearly as long. However, with the advent of the lithium ion capacitor, that is quickly changing.
30 Second Charging, Rechargeable Battery - [Link]
This is Part 2 of a series of blogs regarding the development of a wall-mounted server based on the Raspberry Pi, featuring WiFi and a colour touchscreen. Part 1 can be found here.
The enclosure I’m using, a re-purposed room thermostat casing, places some very tight constraints on the dimensions of the Raspberry Pi and PiTFT board.The plastic used in the case is quite sturdy, and is at least 2mm in thickness. Therefore the real inner depth of the case is about 12mm. As for the width of the Pi, we need to shave at least 4mm from the side. The Pi itself is 86mm wide, same with the PiTFT board, so we will need to find a way of making it closer to 82mm.
Pi On The Wall – wall mounted home server - [Link]
by JamecoElectronics @ instructables.com:
Build a DIY geiger counter that uses a PIN photodiode as a substitute for an expensive Geiger-Mueller tube. It detects alpha and beta radiation particles. The circuit is soldered onto a small protoboard and everything is placed in an aluminum enclosure. Copper tubing and a piece of aluminum foil is used to help filter out noise and RF interference.
Pocket Photodiode Geiger Counter - [Link]
Here’s a cool Solar scare mosquito project by Gallactronics. He writes:
So I built a device that generates air bubbles at regular intervals and effectively produces ripples up to a radius of 2 meters (sufficient for most urban water bodies). The device automatically switches on when it comes in contact with water an alarm alerts if the water body dries up or someone tries to remove the device from water. At less than $10, the device is cost effective and being solar powered, it is energy independent and maintenance-free.
Solar scare mosquito - [Link]
by ASCAS @ instructables.com:
Have you ever wanted to broadcast your own radio station within the neighborhood? Ever get curious on where people get those “Surveillance Bugs” from spy and action movies? This small and simple FM transmitter is the toy that geeks have always wanted.
FM transmitters can be complicated to build, that’s why I’m teaching you how to make a foolproof FM transmitter. There’s no need to buy kits, this tutorial includes the PCB layout and the schematics. It has a range of up to 1/4 mile or more. It’s great for room monitoring, baby listening and nature research.
The Ultimate FM Transmitter (Long Range Spybug) - [Link]
When you start hooking peripherals such as keyboard, WiFi dongle and mouse to a Raspberry Pi it’s not long before you run out of ports and need a USB hub, preferably powered so that it can supply the RPi as well. At this point cabling starts to take over your workspace.
The Raspiado board, launched on Kickstarter should help cut down on the tangle; it has the same dimensions as the RPi board and mounts on its underside via two (stackable) standoff pillars to leave the top GPIO and camera connectors open to whatever you’re building so that it won’t impede the RPi’s connectivity options.
Raspberry Pi without the Spaghetti - [Link]
by BasinStreetDesign @ instructables.com:
I had a bunch of random inductors in some random drawers and I wanted to know what values they were. These values are quite often not obvious by looking at the device. Colour codes for old ones were not standardized and some of the coloured rings on inductors can be faded or discoloured so that its impossible to tell what they are. Others may be unmarked and any that are hand-wound are just guess work without a meter. So I decided to make an inductance and capacitance meter which would be fairly accurate and work over several decades of value from a few nano-Henries to a few milli-Henries and also from a few pico-farads to about a micro-farad (hopefully). Sounded easy – what could go wrong?
Inductance/Capacitance Meter Saga - [Link]
Programmable DC, AC, current- and high-voltage power supplies, electronic loads, UPS, inverters and chargers of small and high power suitable for production and servicing – this is Elektro Automatik.
When we establish a production or testing workplace, we usually can´t omit a suitable power supply. Sometimes a „universal“ like 2x30V/3A is sufficient, but often not. It´s well known fact for those of you, who produce devices various devices requiring higher current or higher voltage. Typical representatives are equipment for automotive industry, various drives, backup sources, solar devices etc. In these case tens to hundreds Amps and/or hundreds to thousands of Volts are no rarity.
Right for these purposes, German company Elektro Automatik produces devices and systems for power supply and simulation of conditions in a real operation. Adjustable DC and AC power supplies, current sources, electronic loads and other devices can serve for a thorough examination of your devices even in “border conditions” and they can help to discover eventual hidden faults which might occur later in a real operation. Many Elektro Automatik products are programmable and they´re also connectable to some of common buses like CANopen, Profibus, ProfiNet, DeviceNet, Modbus, Ethernet and also RS232. Also interesting are for example electronic loads with energy recovery, where the lost energy doesn´t transform to heat but returns back to mains line with efficiency of about 93%.
Upon request, we´re able to provide you with any product from the Electro Automatik catalogue (14,5 MB).
Where common power supplies end, there the Elektro Automatik begins - [Link]
by Annikken @ instructables.com:
This waveform generator is based on the work by Amanda Ghassaei. Waveform generators (or function generators) are used for testing and debugging circuits. e.g. frequency response of op amp or sensors. This waveform generator is powered by Arduino with Annikken Andee shield – a device that lets users create iOS/Android interfaces without iOS or Android programming at all. It outputs sine, triangle, saw and square waves. Frequency is controlled by means of a slider (on iOS/Android device) and wave type is selected using on screen iOS/Android button. With a iOS/Android interface, you can add certain features not possible with hardware buttons. E.g. displaying different ranges of frequencies for each wave type, displaying meaningful controls for certain wave types. For example, the pulse width modulation slider is only visible for square wave types, its not visible for sine, triangle or saw wave forms.
IOS-Controlled Arduino waveform generator - [Link]