This is the main building block of the home automation system. My goal here was to design one circuit board that could be customized for different functions by selectively populating the board, adding daughter boards, and changing the software. Currently, this board is used to implement the functionality of a network connected light switch, a ther
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mostat, interfacing a keypad to the CANOpen network, and implementing basic analog and digital I/O functionality. In terms of form factor, the board is a drop-in replacement for a decora style light switch, and can be used with any decora trim plate you pick at your favorite retail store. The actual switch plate seen on the right is a 1/8" (3mm) thick piece of acrylic, which can be custom engraved if desired. Since it is translucent, you can see the status LED`s through the plate - and yes, pick any color you like. The rest of this document describes the electrical and mechanical design of the board populated as a switch The schematic below shows the essential components of the circuit, the Thermostat specific components in the red box are not populated if you are building a switch: The CPU that is used for this module is either a PIC 18F248 or 18F258. While they are pin compatible, the latter has twice the amount of memory available, and is required if you want to implement more complex software. The former is a little cheaper but will only allow you to implement the functionality of the basic switch described here. Currently, Microchip seems to be phasing out both of these chips and replacing them with the PIC 18F2480 and 18F2580. While these are supposed to be compatible with the -248 and -258, I have not tried to recompile and run any of the software for these newer chips. The CAN bus connector is a MTA type polarized...
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....
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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....
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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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