With a bit of adeptness, you can build an electronic scales based on a servo motor. Depending on the type of servo you use, it can measure weights of up to around five kilograms (11 lbs) with reasonable accuracy. If you examine the operating principle of a servo motor in more detail (Figure1a), you can see that in simple terms, it consists of a control loop that
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uses a potentiometer to convert the motor position to a voltage that is compared to the voltage from a PWM converter. Based in this information, the motor is rotated so that its measured position corresponds to the desired position (U2 = U1). As can be seen from Figure1, all you need for a scales based on a servo motor is a square-wave oscillator that supplies a signal at a constant frequency of around 50 Hz with a f ixed duty cycle of approximately 10%. This defines a fixed setting for the position of the motor axle. If a mechanical force tries to rotate the motor axle in this situation, the servo control loop adjusts the drive signal to the motor to counteract the rotational force. The motor thus has to supply an opposing force, and that costs power, with the result that the current through the motor increases. With a type RS-2 servo, this current can rise to as much as 1 A, while the quiescent current is no more than a few dozen milliampG¨res. If you attach an arm to the motor axle and fit it with a weighing pan, and then connect an ammeter in the servo supply line, you have a sort of simple electronic scales. The scales can be calibrated using a reference weight, with the length of the arm set to produce a certain amount of current with a certain weight, such as 0. 5 A with 1 kg. Two kilograms would then draw 1 A, and so on. The scales can also generate a voltage out-put if you measure the voltage across a sense...
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....
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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....
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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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