The circuit comprises two sections: charger power supply and LED driver.The charger power supply section is built around 3-terminal adjustable regulator (IC1) LM317, while the LED driver section is built around transistor BD140(T2). In the charger power....

Very little extra circuitry is needed to do both forword and backword walking sequences along with a few other tricks. The PIC16F818 has a lot of features that work well in this situation. As you can see from the Schematic and Source Listing, position....

For normal use it`s necessary to connect the battery, when the jumper is connected. Please take care, that the transmitter is on and the throttle is set to "power off"...

Transient overloads are not short circuits but can push the power supply above its nominal load value. This scenario occurs with typical loads such as printer heads and small motors. When facing such a load profile, the power supply can easily trigger its....

Me and a friend are both trying to build a millipede. Because of obvious reasons, the millipede is NOT going to have 1000 feet!!! Instead, it`s going to have 16 pager motors as feet. It will also have 3 MicroMotors to ``bend`` towards light, and a backup....

This application note describes how to implement a compact size and high-speed interrupt driven step motor controller. Step motors are typically used in applications like camera zoom/film feeder, fax machines, printers, copying machines, paper feeders/....

This circuit has been designed to alert the vehicle driver that he has reached the maximum fixed speed limit (i.e. in a motorway). It eliminates the necessity of looking at the tachometer and to be distracted from driving. There is a strict relation between....

The 555 Stepper Pulse Generator kit will help you with the pulse required to drive your favorite DC Servo Motor application. This kit uses the famous 555 timer IC for generating the Stepping Pulse...

This FM transmitter has a number of features, with a volume control to adjust the input level and a small, neat box to make it easier to attach to a guitar. The volume control is positioned at the end and when turned up fully, the transmitter provides fuzz....

This is easy to install to the usual system. You have to find a wire which has a voltage in position `1` and then You cut that wire. After that You install the "ADAPWIPE" between the break of wire just like the circuits diagram....

In Fig.1 A precision DC under?voltage relay switch. The opamp is wind as a voltage comparator, with a reference voltage applied to pin 2 and the test voltage applied to pin 3: the relay turns on when the pin 3 voltage exceeds that of pin 2. The circuit can....

From 230 V AC a DC supply of + 5 V is obtained. The power supply is given to the other blocks. The pulse generator at a particular frequency generates the clock pulses. The clock pulses are counted by a counter and gives output after every 10 pulses. The....

Sensing unit consists of infrared emitter OP295 to produce the infrared beam, & two detectors in front of the emitter to detect the infrared beam OP598. Since the main idea in this device is to know person direction; and so, to get this approach, we have to....

This circuit leads palmorefmata coils,, engine. Each coil is driven by a transistor type Darlington. Darlington Transistors internally comprise two transistors connected in series. The "hfe" Darlington is equal to the multiplication of "hfe" of both its....

In order to simplify the transmitter design, we've used the new pll circuit from Motorola :the MC145170. This PLL includes the prescaler and a serial standard bus called SPI. We advise to use the P2 version that fixes some init issues during the Power Up.....

The interface uses a PIC16F876 microcontroller and not much else. It performs channel mixing, current limiting, and noise rejection. Push the stick forward, both motors move forward, move the stick to the left and the robot moves left. It makes the robot....

The circuit in Figure 1 uses a Centronics printer port to interface an eight-channel, 8-bit ADC to a PC. The circuit cuts the cost of addressing and decoder circuitry and saves one expansion slot for interfacing. The design uses three of the subport`s....

The diac is a common component used to trigger triacs. The construction of a diac is similar to that with a transistor, but with both junctions doped to similar levels so that the two junctions' revers break down characteristics are similar. This is a fun....

This project provides an simple F1 motor racing style 5 light race start sequence with a random delay that you can use on a real race track, kart circuit or even your slot-car circuit. Operation is simple; when the start button is pressed all the LED....

The heart of the clock is a PIC 16f628A microcontroller (PDF). This microcontroller has an internal oscillator however an external 20MHz crystal oscillator is being used since it will have to accurately keep track of time for weeks and months. The....

This is a very simple circuit to interface a current loop sensor to an input which is designed for a voltage, such as that from a standard potentiometer. This page is technical so that interested persons can build the circuit themselves, but 4QD can also....

A motor driver! I'm sure you knew that already but that's what it is. A motor driver is required in pretty much all walkers including all of my CW series walkers. You need to use it any time you need to supply more current to the motors because the circuit....

The target of this project was the design of a small portable mixer supplied by a 9V PP3 battery, keeping high quality performance. The mixer is formed assembling three main modules that can be varied in number and/or disposition to suit everyone needs...

This encoder can transmit the state of up to 16 TTL digital inputs using an RF or infrared transmitter. When enabled, the included modulator automatically generates the 38kHz IR carrier. Containing a PIC microcontroller, the circuit is very flexible. You....

The circuit below provides the horizontal drive voltage. The supply voltage on one end, +135 to +165, is made variable for the horizontal position control...

Controlling a small dc motor without speed control sounds like a trivial task; a switch or a relay should suffice. However, several problems accompany this approach. For one, the switch, because of the inductive load and the low starting resistance of the....

Figure 2 is a diagram of the control circuit built on a 1.45 X 1.8 inch PC board. IC1 is an LMC555 CMOS timer that generates a 200 microsecond wide clock pulses to step the motor and control its speed. The speed can be varied by changing the pulse....

The output voltage is = 0.707 x Vin, at the center posititon. The output voltage is = Vin, at either extreme position...

During the development of systems that include small motors, a simple, bidirectional motor controller with speed adjustment may be helpful. Figure 1 shows such a controller. The circuit uses everyday components whose tolerances and ratings are unimportant as....

This board is designed specifically to control the 5-motor Robot Arm sold by Baycom Technologies. It has no input facilities, but it is less expensive than combining the I/O Board with the Relay sub-Board. If you need lots of relays and no input, this is the....

I have had requests to add a VHF FM transmitter, to the QRP collection. This project is a simple transmitter using only one crystal and will cover 145.00 to 146.00 MHz. The crystal is a 44.9333 MHz crystal for 145.500 receive, as used in the Trio (Kenwood)....

LVDTs (linear variable differential transformers) are electromechanical measuring devices that convert the position of a magnetic core into electrical signals. You generate these signals via excitation on the primary side. The results on the secondary....