The P5 design uses only eight 74HC/AC240 chips which are all octal inverting buffers. Each 74HC/AC240 chip has two groups of four inverters each controlled by a tri-state enable pin (pin 1 and 19). The 74AC240 chips (U1-U5) are used as H-bridge style motor drivers since they have almost double the drive current compared to 74HC240 chips. These mot
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or driver chips are permanently enabled by grounding control pins 1 and 19. The two groups each have four inputs connected in common to a bicore output and the four outputs are connected in common to one motor winding terminal. Since each bicore has two complementary outputs the voltage across the motor winding causes the motor to rotate back and forth. The 74HC240 chips U6 and U7 are each used to form a master - slave bicore pair with reverser. The inverters used for the bicore s are permanently enabled by grounding pin 1. The inverters used for reversing are turned on or off with the tri-state enable pin 19. Only 2 of the 4 tristate inverters are used conventionally for reversing the phase of the slave bicore s while the other two are put to a novel use: one inverter is used to provide positive feedback to the enable pin and the second spare inverter is used to turn on a RED flashing LED when the reverser is active. The flashing LED also provides diagnostic visual indication of the operation of the slave bicore. The 74HC240 chip used for U8 provides a reverser and a slave bicore for the waist motor as well as a monocore (a. k. a High Low Oscillator) photobridge comparator which controls the phasing of the front and rear motors. I) The photobridge comparator uses 2 inverter s from U8 connected in series as an voltage controlled oscillator with complementary outputs to generate three states : If the left photodiode gets...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
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....
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....
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....
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....
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,....
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....
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....
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.....
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