Tag Archives: receiver

Simple Infrared Barrier


by Maurizio @ dev.emcelettronica.com:

Although a remote control is not so difficult to design and build, there is an even simpler option: the IR barrier. This consists of a constant IR signal permanently going from an emitter to a receiver, both of them being in two different places (a few meters apart). When an obstacle comes in between the emitter and the receiver, the IR signal is blocked and the receiver senses that it is missing, flagging the event in an appropriate manner (figure 1).

The principle of operation is simple enough, and with most components taken off the shelf, it is easy to design the schematic. The IR element in the emitter is a simple IR LED. This behaves absolutely like any other LED, with the sole exception that it emits light in the infrared spectrum. The emitted light is thus invisible to human eye, but it is meant to excite the infrared receiving element on the other side of the barrier. One important element of this LED is the wavelength of the emitted light, of which we already know that is in the infrared spectrum.

Simple Infrared Barrier – [Link]

Simple Acoustic Guitar Sound Receiver

This design of acoustic sound receiver features low power operational amplifier. It has rail-to-rail input/output and 0.85mA supply current per amplifier. It uses piezo speaker as its microphone that can be attached to easily due to its size and dimension.

The circuit is comprised of MCP6L91RT-E/OT 10 MHz, 850 µA operational amplifier that is used to amplify the sound signal. The low-pass filter is used to allow low frequency signal to pass while attenuating high frequency signal or above cut-off frequency of the system to prevent distortions and unnecessary signal. The piezo speaker is used as a microphone or a sound receiver in this circuit. Its size and dimensions is well suited for this application.

The circuit is suitable for different types of acoustic guitar. Since it can be attached easily, the old and other traditional instruments can be developed and modified so that it can continue its service even for the digital era. It can be interfaced to different applications which is not limited to musical instrument.

Simple Acoustic Guitar Sound Receiver – [Link]

VHF Aircraft radio communications receiver


Dilshan Jayakody published a new build, a VHF Aircraft radio communications receiver:

This is simple radio receiver project which is capable to receive aviation radio voice signals which are transmit between 118MHz to 138MHz in AM (A3E). We got initial idea of this project by reading Sverre Holm’s (LA3ZA) article about “cheap VHF receiver project

Simple Lightning Detector


Lightning detector that flashes when lightning strikes nearby.


This circuit picks up and amplifies signals in the 300 kHz range, where lightning makes a lot of noise that can be picked up with a radio.  The antenna and receiver are tuned to 300 kHz, with the receiver’s output connected to an amplifier that drives the lamp flashing circuit, alerting you to lightning in the area.

Use the potentiometer to reduce the sensitivity to noise and still be able to detect lightning strikes.  In addition to lightning, this circuit will also respond to noise from motors inside appliances like refrigerators, washers, and air-conditioners.  Another easy way to affect the sensitivity is to take off the antenna, or lengthen it depending on the conditions.  To get some confirmation while tuning the detector, you can tune an AM radio to the bottom the of the dial as well.

You can use this circuit to track weather, and be prepared for it. The circuit is small enough and can be placed in a project box or waterproof container to use, on a boat for instance.  The lamp can be replaced or even used alongside a buzzer in this circuit to give an audible alert as well, so that constant monitoring of the circuit is not necessary.

Simple Lightning Detector – [Link]

Simple AM Receiver Project


A small, simple AM receiver project.  This AM receiver can pick up medium wave stations in your area


This circuit can use general purpose transistors, and in this example there are 3 BC109C transistors.  In this schematic and BOM there is a 200uH inductor and a trimmer 150-500pF capacitor, though these parts can be salvaged from an old AM radio, to preserve the directional nature of a tuning coil, and an adjustment knob (plate capacitor) that work well for radio reception.

The 120k resistor is for regenerative feedback between the Q2 NPN transistor and the input to the tank circuit.  The value of this resistor is important to the performance of the entire circuit.  In fact, it may be better to replace the fixed value with a variable resistor paired with a fixed resistor to adjust the oscillation and sensitivity of the circuit.  All the connections in this circuit should be short to minimize interference.

Performance of the circuit will vary depending on stray capacitance in your layout, the inductor winding/core/length, etc.  Changing values of some of the capacitors, or adding them, as well as a potentiometer in the feedback loop can help with the performance of the receiver.  With such a small circuit that is affected so much by its construction and its environment, a lot of hand tuning and experimentation will be fun, instructive, and possibly necessary to make it work best.

Simple AM Receiver Project – [Link]

Turn an Old DirecTV Receiver into a Hard Drive


With DVR becoming increasingly common over the last few years, DirecTV has sought to distinguish its offerings on that front with multiple levels of service. At the top of the DirecTV DVR receiver options, the Genie offers a huge array of features on a powerful piece of hardware. You can get the newest Genie by signing up for DirecTV using www.SaveonTVDirect.com.  For the average user, this means a better viewing experience; for the advanced user, this means the opportunity for interesting hacks; for the enterprising salvager, this means useful parts to collect from an unused or broken unit.

So let’s talk about all the uses you can get out of a Genie, whatever your experience level or goals. Continue reading Turn an Old DirecTV Receiver into a Hard Drive

VHF FM Aircraft receiver


VHF FM Aircraft receiver:

VHF FM Aircraft Receiver is a superregenative receiver developed for listening to FM transmitters but also tunes the aircraft band and the top portion of the FM broadcast band. Receives both AM and FM (107mHz to 135 MHz). You can use this receiver with the any FM transmitter. The receiver is amazingly simple using only one transistor for the receiver section and one IC for the audio section. This circuit is a self-quenching regenerative RF receiver also known as a superregenerative receiver.


VHF FM Aircraft receiver – [Link]