A team of Columbia Engineering researchers, led by Mechanical Engineering Professor James Hone and Electrical Engineering Professor Kenneth Shepard, exploring the properties of graphene have demonstrated a new electro-mechanical resonant component.
The resonator’s structure consists of a 2-4 micrometer long strip of graphene suspended over a metal gate electrode. The strip of graphene has a natural resonance governed by its physical dimension and is used in the demonstration as the frequency determining element in an RF feedback oscillator circuit. Applying a voltage to the gate electrode stresses and deflects the graphene strip changing its resonant frequency. The team applied baseband audio and tones to the gate electrode to produce a 100 MHz FM signal.[via]
Tiny FM Transmitter uses Voltage Controlled Graphene Resonator - [Link]
This is a VCO FM Transmitter with range 500m – 4km depending on antenna used
- Power supply: 12-14 V stab., 100 mA
- RF power: 400 mW
- Impedance: 50-75 ohm
- Frequency range: 87,5-108 MHz
- Modulation: wideband FM
FM VCO Transmitter - [Link]
Ray Wang writes:
Hi, I recently built a reflow toaster oven using an Arduino. I know it’s pretty standard stuff, but my version has an automatic oven door opener (using a servo) and circulation fan to speed up the cooling time, and remote notification using an RF transmitter
Reflow toaster oven using an Arduino - [Link]
The compact FPV system I have built is only about 20g, now even my mini quadcopter and micro hexacopter can carry this FPV camera and video transmitter. In this post I will share with you what are the parts you will need and how I made it.
Super light weight RC FPV quadcopter DIY solution - [Link]
This is a small circuit with two maxim’s ic, MAX4467 as microphone amplifier and MAX406 as VCO FM transmitter. It’s suitable for short range FM transmittion aka wireless FM microphone.
Here is a very simple, inexpensive and interesting project which provides lot of fun to a home experimenter or hobbyist. This simple transmitter can transmit speech over a short range. It can be used as a simple cordless microphone. The circuit uses two integrated circuits from Maxim. IC1 a MAX4467, is an amplifier raising the microphone signal to a level suitable for frequency modulation (FM). IC2 is a voltage-controlled oscillator (VCO) with integrated varactor (a.k.a. varicap diode).
FM Transmitter MAX4467 & MAX2606 - [Link]
This article shows you how to build a very simple FM transmitter from thirteen components, a Printed Circuit Board (PCB) and a 9v battery. This project was designed to be mounted on a PCB, however you don’t have to. You could construct the project on Vero board (strip board) or any other 0.1” pitch style of project board. If you just want to experiment with this circuit, you don’t even need a board; you can just solder the component s together and let the completed project just rest on the work top. No matter which style you choose, try to keep all component leads nice and short. You could also make the PCB much smaller than the one shown here which is approx. 3 cm square. This is a good size to keep the unit small but nicer to work on for beginners. If you wanted to make one really small, you could use all SMT parts.
Simple FM Transmitter - [Link]
This project goes through the process of designing and building a simple RF transmitter and RF receiver pair that operate at 27 MHz. Only basic parts like 555 timers and 2N2222 transistors are used to make the modules, so it’s generic but fun.
PureVLC brings its first Visible Light Communication (VLC) product to the market. VLC transmits data wirelessly using visible light as its medium instead of radio waves. VLC was demonstrated over a year ago when Harold Haas, professor of Mobile Communications at the University of Edinburgh, successfully demonstrated the technology at a TED conference. He streamed a HD video to a screen using a LED light bulb as transmitter.
Using the visible light spectrum to transfer data wirelessly will ease the burden on the overcrowded radio frequencies. The visible light spectrum is 10,000 larger than that of radio. VLC can potentially realize ultra-high-speed transfer rates and high data density. [via]
LEDs Just Got Brighter, They Now Talk Too - [Link]
Scott @ swharden.com writes:
Last week I spoke with a student in the UF aerospace engineering department who told me he was working with a group of high school students to add a payload to a high-altitude balloon being launched at (and tracked by) NASA. We tossed around a few ideas about what to put on it, and we decided it was worth a try to add a transmitter. I’ll slowly add to this post as the project unfolds, but with only 2 days to prepare (wow!) I picked a simplistic design which should be extremely easy to understand by everyone.
High Altitude Balloon Transmitter - [Link]
This small transmitter can reach more than 1 km under good conditions . The input can either be an electret microphone or other audio source. The frequency is given by CV (trimmer common 2-20 or 3-30pF) and L1 4 or 5 turns of 22 AWG enameled wire with a diameter of 1 cm with air core.
FM transmitter with 2N2218 - [Link]