This project illustrates how to use an ATTiny microcontroller and an RGB LED to create a coloured light that cyles continuously through random colours, but changes colour dramatically at the press of a switch. Why My kids had this $2 novelty pen that did this employing a teensy circuit along with 3x3mm LEDs and some alkaline coin-cells.
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If children will play with this, choose one of the following: ensure your LED is not a superbright, or use a diffuse led, or diffuse a clear one (eg cover it with half a table tennis ball, or enclose it in resin or wax. You could also use higher-value resistors to limit current, or lower PWM_OC_MAX to limit the PWM duty-cycle (LED brightness) via software. The microcontroller should be configured to obtain the system clock from the 8MHz internal RC oscillator. The ATTiny13 factory fuse settings include a divide-by-8 of the RC oscillator giving 1MHz, so remember to change that fuse to get the original 8MHz signal. The overflow interrupt from the hardware 8-bit timer triggers an interrupt service routine (roughly 32000 times per second) which increments each of 3 separate 8 bit counters. These counters, and corresponding "Output Compare" (OC) values are used to generate 3 Pulse-Width-Modulated waveforms, with each counter being associated with a particular output pin. Every time a counter reaches zero, the corresponding pin is turned on. When the counter reaches its PWM_OC value it is turned off. When the counter reaches its PWM_TOP value (255) it wraps around to zero and the cycle repeats. The effect of all this is that each of the 3 output pins is driven with a square-wave having a wave-legnth of 256 timer ticks (about 1/128 of a second), which is equivalent to a frequency of 128Hz (cycles-per-second). The OC value...
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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