One of the goals of Movable Party is to provide an interactive experience for audiences/participants. Since power will be generated from a hub motor attached to the rear wheel of each bike (see this post ), the speed of the rear wheel directly translates to the amount of power generated. Detecting how fast the rear wheel is moving thus seems likethe most obvious/important piece of data to capture
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from these stationary, power-generating bikes. The easiest way to detect the speed of the rear wheel (the way most bike computers work), is to make a tachometer simply put, a revolution counter. By counting the number of revolutions over a certain period of time, we can determine how fast the wheel is turning. Basically, you want to count the number of times a specific spot on the wheel crosses a point of measurement, and divide by some time constant (e. g. Revolutions per Minute, RPMs). Electronically, you are triggering a switch every time this point on the wheel passes a fixed sensor. Because the wheel is turning and the sensor is fixed, using a mechanical switch where there is contact every rotation will not work very well. For example, the mechanical switch will cause friction every rotation. Also, maintaining perfect distance between the wheel and the switch will be difficult. Instead, there are two common ways of detecting rotation that do not require contact between the sensor and the wheel optically and magnetically. Due to my own personal familiarity with magnetic circuits, as well as the expense of using an optical system and concerns about the functionality of that system in ambient light, I have decided to pursue magnetic sensing. To construct a tachometer using a magnet, you attach the magnet to the wheel, and attach a sensor to the fork (at a fixed position). As the magnet passes by the sensor, it triggers a...
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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