Briefly, the circuit works as follows; the clock signal drives 4 D-flipflops in the control section which store the on/off state of each of the current directions for the two stepper motor coils. The flipflops comprise a FSM (finite state machine) which advances to the next step of a half-stepping sequence on each rising clock edge. The drive sect
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ion provides the current-driving capabilities to turn the control signals into coil-driving currents. The drive section also includes protection diodes to prevent back-EMF from the motor coils from destroying the NTE1749/L293 IC. This circuit is designed to power a 12V stepper motor, and use 5V for logic. If your stepper is not 12V capable the circuit will require modification. The circuit can be powered with a standard 12V lead-acid battery. Stepper motor speed is controled by how fast the current direction is switched through the coils (hmm, current direction switched, sound familiar like AC power ). The first step in controlling stepper speed is to generate a clock signal to run the d-flipflops in the control section. The frequency of this clock signal controls how fast the motor steps. The clock generation circuit shows one way of generating a square-wave signal (clock) at a specific freqeuncy. There are many good sites which describe the operation of the 555 timer IC used in this circuit, such as this one at the university of Guelph. The frequency of the square wave produced by the 555 is controled by the 0. 18uF capacitor and the 10k pot / 23k resistors. Timing is generated from the charging and discharging of the capacitor through the resistors. The switch between 2. 2k and 23k for R1 selects track (noraml) or slew (fast) modes. The 10k pot allows fine adjustment of the exact tracking speed. The 10nF capacitor...
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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