How to make the hardware connections between the Raspberry Pi and the house wiring. Check out this post if you want a PCB that does the connections for you. In my house (and the vast majority of others) the thermostat wiring runs at 24V AC. There`s a live wire (or two, depending on the setup) coming into the thermostat, and several others leaving to control
Click here to download the full size of the above Circuit.
the different components of the HVAC system. The thermostat`s job is to close the circuit between the live wire and the appropriate control wire based on the temperature. A relay is an easy way to do it, but I find relay`s cumbersome with their (usually) breadboard unfriendly pin layout and larger-than-can-be-supplied-by-gpio switching current requirements. I have found, in my opinion, a much better way of switching AC current: the TRIAC. If you`ve ever used a MOSFET for DC current switching, a TRIAC is similar in application (but not physics), only for AC current. There are some important differences, however. Probably the biggest difference is that once a TRIAC is activated, it will not deactivate until the current through it drops below some small threshold current, and I`m not talking about the gate current. Because of this the TRIAC is pretty useless for DC since once there`s current flowing it will never drop (unless you have another switch somewhere, which kinda defeats the purpose, or the battery dies. ). In AC, the voltage (and hence current) will go to zero twice every cycle, so shutting the thing off is not an issue. An important side effect of this is that it`s impossible to switch a TRIAC faster than the frequency of the AC line it`s connected to, so you can forget about using it for PWM. But you CAN control when in the cycle it turns on to control the average current flow available to whatever it`s connected...
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.....
characters left: