The infra-red receiver requires the infra-red light to be modulated at 38 kHz, this is quivalent to a period of 26 µs. The specifications on the receiver suggested using a 50% duty cycle. We found however that this did not work the way we intended. To overcome this we reduced the duty cycle to 5%. The infra-red sources used were 6mm infra-red (88
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0 nm) LEDs. Using a bank of four of these LED`s across the front of the robot gave an even coverage in the sensor ’s field of view. To modulate the light we drove the infra red LEDs using a 555 timer chip. This timer was tuned using a trimpot to give exactly 38 kHz, which is the receiver ’s centre frequency, however the receiver is susceptible to frequencies between 25 khz and 60 kHz. The output pin of this timer chip drove the two infra-red LEDs. An ATMEL 89C2051 micro controller was used to control the operation of the dieBot. The benefit of using a micro controller is that the function of the robot can be reprogrammed. This allows for easy design, redevelopment and dubugging. The two inputs to the micro were the outputs from the left and right infra red sensors. There were four outputs from the micro that were connected the motor driving circuit (L293E). The logic of the controller was simple, if the robot sensed a object on the left it would turn right and visa versa. We found difficulties that the robot was very apprehensive when it approached an obstacle. It was found that the ouput signal from the infra red receivers was a digital signal and flickered greatly before changing state. Some form of filtering had to be performed on the input signal. A crude form of filterering was achieved by waiting for the transmitter to detect high for a period of 0. 1 seconds before actually sensing an object. This method of filtering...
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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