The Arduino microcontroller board is able to supply a current of 40mA from its output connections. These digital outputs are fixed at 5V ON or 0V OFF . This is adequate for working with LEDs but devices such as motors, solenoids, high brightness LEDs etc. may require much higher currents and voltages. To achieve this an interface in between t
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he Arduino and the device can be made from locally sourced components. Suitable transistors can be found in a wide variety of waste electronic items. Internet resources are available to check part numbers for a components specification and, interestingly, retail price. In the following example all the components were found in a discarded ATX computer power supply. The circuit can also be used with other inductive loads, such as solenoids and relays. For other, non-inductive, loads (LEDs etc. ) the protection diode D1 can be omitted. In this example the ATX components used were: This circuit has been initially tested with 12V motors drawing 500mA without a heatsink. This is more than adequate for initial experiments in the FabLab, though it may be worth noting that the transistor is rated at 400V and 3A. The H-bridge circuit enables a motor to be spun in either direction and stopped from two control inputs. A steerable robot can be made using this circuit, together with a second circuit and DC motor. This circuit was made using components taken from various discarded sources and previous projects. The LEDs were added to aid debugging and comparing the performance of different DC motors. The transistors used are relatively low current devices but have been tested driving motors sourced from printers up to 250mA. A second, more powerful, circuit will be built when a suitable source of pnp transistors is found to complement...
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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