Vacuum Tubes Valves
Musical & effects
Yagi Uda Antennas
Metal Detector Circuits
Liquid Sensing Circuits
Light Sensing Circuits
Voltage Detector Circuits
Air-Gas Detection Circuits
Human Sensing Circuits
RF & Radiation
Optical Sensing Circuits
Free Energy Circuits
AC to DC & DC to DC
Solar Cell Circuits
Micro Power Circuits
Switching Power Supplies
Light Laser LED
Digital to Analog
Analog to Digital
Data Bus Circuits
Voltage to Pulse
Current to Voltage
Frequency to Voltage
RF Converter Circuits
Sine to Square Wave
Voltage to Current
voltage to frequency
Period to Voltage
Video Wall circuits
TV Video Circuits
Motor Control Circuits
8051 / 8052
PCB CAD Software
Car bike Circuits
555 Timer Circuits
Remote Control Toy
H Bridge Circuit
DIY HV Variable Cap
DIY PMA alternator
Interconnection & Timing
Digital Signal Integrity
Digital & Bipolars
Sensors & Detectors
Regulated Power Supply
4 Band Resistor
5 Band resistor
6 Band resistor
RC Model Toy Circuits
RC Model Toy Circuits
Model rocket launcher
The circuit consists of the launch timer itself and an automatic-off timer. When power is applied to that IC, the countdown LED's sequence is on until they are all lit. When the last one LED1, is fully lit, transistor Ql saturates, energizing RY2. When that happens, a circuit between the lantern battery at the launch pad and the nickel-chromium...
Simple Utility Mixer
Here"s an interesting mixer circuit. With it you can effectively combine signals from audio to high-fre-quency RF. Als
Model Train And Slot-Car Controller
As shown, a 555 timer (Ul) is configured as an astable multivibrator (oscillator) with a 400:1 duty cyc
Model Railroad OdometerCar
The Car shows the distance a train travels on a 5 digit LCD display. The distance is indicated down to 1/100th of a mile (about the length of a 50 foot car) with an accuracy of approximately plus 2 percent using a standard 33 inch freight car wheel. Simply stated, the Odometer Car counts the number of revolutions of one of the axles,...
Speed Controler for R/C Models
Here`s how you can make an electronic speed controler (ESC) for your remote control car, boat or even an airplane using an old servo and some MOSFETS. Please note that this ESC has a very limited control range. Meanining that it will act almost like but better then a switch.
High Speed NiCd Charger for R/C
It can safely charge a 7-cell RC2000 pack in about 14 minutes, and an RC2400 or CP2400SCR pack in about 17 minutes. As a NiCd cell is being charged, two things happen which affect its temperature. Due to resistive losses within the cell, some of the charging current is converted to heat (I2R losses). At the same time, the chemical reaction that...
R/C Thermal Peak Detection NiCd Charger
The charger described in this article can charge packs of 4 to 7 cells with capacities ranging from 600mAh to 2Ah. The charger automatically begins charging when a pack is connected. It charges at a (nearly) constant current (adjustable), and terminates the charge when the pack begins to get warm (a NiCd pack begins to warm up when it has...
Infra Red Switch remote control
This is a single channel (on / off) universal switch that may be used with any Infra Red remote control using 36-38kHz. (This is a very common remote handset frequency). Any "button" of any remote control may be used to work this universal switch. The button must be pressed for about one and a half seconds (determined by R3 and C2) before the...
Hot Wire Foam Cutter project
I leave it to the reader to supply their own power supply. I am using a supply from an old external SCSI drive. My cutter runs from the five volt supply and 25cm of nichrome wire pulls about 900mA or 4.5 watts. That is actually running a little hot and I plan on building a temperature control circuit shortly. I have read that the key to...
Hot Wire Foam Cutter
Hot wire foam cutters are used by hobbyists of all stripes to contour Styrofoam into a vast array of shapes for a wide variety of uses. Model railroad builders shape foam into landscapes. RC plane builders shape foam into aircraft wings and fuselages. Stagehands shape foam for theatrical sets and props. And because Fiberglas can be applied over...
A signal braking module
M½´rklin`s signal braking module, number 72441, solves this problem by introducing a short transition track between ordinary and braking section, and additionally offers a emergency stop section with cut off power in case a loco does not brake in appropriate distance. Let me call this kind of braking module a "conventional brake module". My...
Model Railroad Group SCR Throttle
It was designed for use on a "The London Model Railroad Group`s" large O scale layout located at London, Ontario, Canada. The prime requirements for the club throttles were that they be rugged, reliable and produce as little heat as possible. Throttles of this type have been in service at the club since 1987 with excellent results. The throttle...
8 Pad Launch Controller
The overall design went through a number of design changes as I tried one option after another and in the end, the simplest one won out. I had tried to utilize all electronic (no relay) circuitry but creating the high power circuits was too much of a challenge and so I reverted back to a mechanical relay design.
IC 2 tones Siren
Double-tone Police sound Single-tone old ambulance sound This circuit is intended for children fun, and can be installed on bicycles, battery powered cars and motorcycles, but also on models and various games and toys. With SW1 positioned as shown in the circuit diagram, the typical dual-tone sound of Police or Fire-brigade cars is generated,...
R/C On/Off Motor Controller with Brake
A relay-based on/off controller on the other hand can be very efficient. A typical relay has a contact resistance of 3 milliOhm. At 20A, this translates to a voltage drop of 0.06 volts, with a power loss of 1.2W. The relay itself typically consumes around 0.4W. And, by using a double throw relay, one gets a brake for free.
Incline Railway Project
The drawings and photos below are for an operating incline railway that was built by the London Model Railroad Group for its `O` scale model railway club located at London, Ontario, Canada. This is a single car model loosely based on a double car incline that operated at Port Stanley, Ontario. The mechanism is driven by a geared slow speed...
Pine Racecar Victory Judge
I have received countless emails asking for a circuit to tell the user which car won in a pine car (also called Pinewood Derby, Cub Car, Scout Car, etc.) race. This simple circuit takes care of the guesswork, lighting the appropriate LED to indicate the winner.
Model rocket launch controller
Eight LED`s are used to indicate the pad currently selected. These LED`s are connected to a decade counter, which sequences the LED`s when it receives a clock pulse.Only one LED can be lit at a time from the decade counter, so although this circuit contains many LED`s only a small drain us placed on the battery. The clock pulse for the decade...
Multi Rocket Launcher
This launch controller can be used with low voltage battery igniters, which fire rocket engines in model rockets such as the Estes range. These circuits are electrical, only switches and contacts are involved. First the circuit for a single rocket.
model train detector using photocell
This photocell is best mounted at tie level between the rails. The variable resistor adjusts the sensitivity of the circuit. This circuit can be powered by either 6 or 12 volts - BE SURE to use the proper relay;
Miniature High-Rate ESC with BEC and Brake
This electronic speed control (ESC) for brushed motors combines the features of two of my earlier designs. One was a high-rate 30A ESC with a brake, and the other a high-rate 12A ESC with a BEC (receiver battery eliminator circuit).
Motor Speed Control with Battery Eliminator Circuit
This design is based on one published by Milan Lulic in the German magazine elektroModell. Mr. Lulic`s design is for surface mount technology (SMT) construction, whereas mine uses standard off-the-shelf components, and is therefore better suited to construction by the hobbyist.
Model Aeroplane Navigation Strobe
If you are interested in model aeroplanes and have the capital, a radio controlled electric park flyer is a must have. An RC aeroplane under 400 grams floats around like the rubber models of my youth and contact with the ground doesn`t seems to involve that sickening crunch that comes with larger models. Finding a deserted park in which to fly...
Model Train Diesel and Horn Circuit
The main power supply to the system must be a regulated 12 volts DC with a minimum input from the train control AC or DC power supply of 13.5 VAC connected to pos 3 and 4 of the rectifier bridge . The ground bus of the regulated 12 volts supply must be connected to the system ground , The independent speed reference voltage is taken directly...
Altitude recording altimeter PIC16c54
No description available.
Hot wire foam cutting
Getting the power from your 110 volt receptacle to a suitable foam cutting format presents several problems. A standard light dimmer can be successfully used to vary the heat, but it can`t heat the wire in a direct circuit. With a light dimmer powered by straight line current, you are taking a great risk of electric shock. Also, a guitar string...
Knightrider lights for model cars
This simple circuit drives 6 LEDs in `Knightrider scanner mode`. Power consumption depends mainly on the type of LEDs used if you use a 7555 (555 CMOS version).
R/C Airplane LED Flasher
This was designed to flash a pair of LEDs to be mounted on the wing tips of a Parkzone Citabria R/C (remote control) airplane. The unmodified Parkzone Citabria only weights 20 grams (about 0.7 oz), so weight, and therefore the number and size of the electrical components for the flasher are critical. Another major constraint was the range of...
autopilot with rev 2.2 board
The servo driver is just simply two 4017 decade counters and lots of 0.1" headers. Only populate the A side headers; the B servo bank is optional and will require a few more header pieces. If you received 20 headers, you'll be short two of them. If you received 25 headers, go ahead and fill it up. You will have to cut the headers to get the 2...
RC transmitter with MC68HC711
The first SUPERTEF version was using a 68HC11 microprocessor in extended mode i.e. with an external memory program which necessitated many integrated circuits (IC) such as the 74C138, 74C373, 68HC24 and 27C64 making the printed circuit board densely populated and prone to defects. Now, SUPERTEF 96 uses a 68HC711E9 that is to say the same basic...
Radio Control Motor speed Interface
The second half controls the steering. The mechanical design is a 3 wheeled caddy with the ´single wheel´ actually a closely spaced pair of wheels which are driven by the main drive motor top provide motive power (this is the motor controlled by the first circuit). However the pair are on a motorised swivel arrangement: this second motor is the...
Batteries for Model Aircraft
A new type of NiMH battery known as HeCell has recently been developed, which is claimed to allow higher discharge rates than the conventional ones (about 12 - 16C).
555 Timer Circuits
H Bridge Circuits
Ultrasonic distance finder circuit
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
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