Using the OBD-II (On Board Diagnostics) protocol, we can read live information from a car`s computer with our NerdKits microcontroller kit, as explained by our guest star, Elena T. , MIT class of 2011. This uses the port under your steering wheel to receive all kinds of information, and is used by auto mechanics for troubleshooting the `Check Engi
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ne" light, and for periodic emissions tests with onboard sensors. In this microcontroller project, we implement the Variable Pulse Width (VPW) protocol, which is generally found on General Motors cars. Please note that if you attempt this project, your car may have a different signaling protocol, which would not be compatible with our code. The car we used was a 1997 Chevy Cavalier. This was introduced soon after the 1996 law requiring US cars to have OBD-II buses, but there are not many sensors accessible from the data bus. On newer cars, you`d find oxygen sensors (allowing you to calculate MPG), but for our demo, we were able to measure: WARNING: Please note that by attempting this project, there are several risks to yourself and your property. This project involves working in the presence of car battery voltage, which can supply dangerous amounts of current and cause fire or electrical damage. This project involves working with your car computer, and while manufacturers do their best to make them robust, it is possible to irreversibly damage your car`s computer or the vehicle itself. And of course, if you`re the driver, you should be focusing on the road, and not some circuit and LCD on your dashboard. Optocouplers (or opto-isolators) provide a way to transmit information without creating a direct electrical connection. In a single small chip package, they have an LED and phototransistor. Current passed through the LED...
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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