Posted on Wednesday, April 9, 2008 • Category: Antennas
If you have a shortwave or high-frequency receiver or scanner that is struggling to capture signals with a short, whip antenna, and you'd like the kind of performance that a 60-foot 'longwire' antenna can provide but lack the space to put one up, consider building the AA-7 HF/VHF/UHF Active Antenna described in this article. The AA-7 is a relatively simple antenna that is designed to amplify signals from 3 to 3000 MegaHertz, including three recognized ranges: 3-30Mhz high-frequency (HF) signals; 3-300Mhz very-high frequency (VHF) signals; 300-3000MHz ultra-high (UHF) frequency signals. Those bands are typically occupied by shortwave, ham, government, and commercial radio signals.
Posted on Wednesday, April 9, 2008 • Category: Remote Control
On these pages, I will introduce Remote Controller with Radio Frequency. The electric wave sending-out is controlled with the code by PIC for transmission and the code is deciphered by PIC for receiving.
Posted on Wednesday, April 9, 2008 • Category: USB Interface Adapters
This article contains information about getting a USB interface working between an 18F4550 PIC and a PC using C# .NET 2.0, using the Microchip-supplied driver mpusbapi.dll. In this article, the PIC is configured using some (slightly modified) demo code originally for the PICDEM FS USB demo board, in which it is configured as a generic class device, with one IN + OUT interrupt endpoint. The device is set up with a bootloader, allowing the PIC to be programmed through software after the initial programming.
Posted on Wednesday, April 9, 2008 • Category: AC / DC Innveters
This is 100W inverter circuit. It uses 4047 IC and IRF540 Mosfet instead of 2N3055 transistor. Power output is 100W from 2-3A transformer.
Posted on Wednesday, April 9, 2008 • Category: LED
It's a little wisp of a circuit that allows you to drive a blue or white LED from a low voltage. Normally, if you want to light up a blue or white LED you need to provide it with 3 - 3.5 V, like from a 3 V lithium coin cell. But a 1.5 V battery like a AA cell simply will not work. But using the Joule Thief, it works like a charm. Not only does it work with a brand new battery, but it works until the battery is nearly dead-- down to 0.3 V. That's well below the point where your other toys will tell you the battery is dead, so it can steal every last joule of energy from the battery (hence the name). To learn how to make one, watch the video, which is available in a variety of formats.
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