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Me and my friend are preparing a senior design project on home automation. I have several things in my mind such as controlling drapes, lights, fans with an IOS application.

We started everything from scratch and came up with a great NTC controlled fan and etched it on a PCB as follows (I can't post more than 2 images unfortunately)

enter image description here

However, here's our bottleneck . Although this circuit works perfectly fine and dandy, this is kind of not we want. We want a user to control the fan, which made us realized this circuit is a total waste because it is independent of the user, turns up the fan when the temperature goes high not when the user wants it to turn up. What we really want to implement is using something that can be controlled with a phone and works as a switch.

How do you think we can do this? We have this in mind : enter image description here

We are writing an IOS app with Xcode and we use ESP8266 Wifi module to bridge our phone to a web server which makes the connection between the phone and system. Do you think we can go from here? If so, what should we do to make this system work ?

Marcus Müller
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Burakhan Aksoy
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2 Answers2

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So far so good. You seem to be on the right track. I am assuming that you are able to send a data packet from your phone to esp module. For ex - You can send a value from 0 to 255 and use it to set the fan speed. 0 being OFF and 255 being ON at full speed.

In your second image, the switch should be replaced with a mosfet which in turn will be switched on/off using a GPIO on esp module. Here is a standard mosfet circuit to get you started:

mosfet

Pin will be connected to a GPIO on esp8266. You drive this pin HIGH, the fan turns ON, you drive the LOW, the fan turns OFF.

+VDD = whatever DC voltage is required for your fan (make sure your mosfet is able to handle the voltage. Also make sure you can drive the mosfet with a 3.3 V signal).

Once you have made the circuit, learn about PWM output on esp pins. To control the fan, the app sends a value to esp and esp sets a PWM duty cycle depending upon the value received.

Whiskeyjack
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    Be sure to specify a MOSFET that will work with the 3.3V drive available from the ESP8266 -- not all of them can. – Dave Tweed Oct 07 '17 at 10:36
  • yeah that too :) – Whiskeyjack Oct 07 '17 at 13:16
  • You mentioned "able to handle the voltage" - it must also be able to handle the continuous and inrush current. It's probably also worth mentioning some sane values of Rin and Rgs, and why they're needed. – Polynomial Oct 07 '17 at 14:12
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To Turn ON And OFF Appliances You Can Use Relay

enter image description here

Connect The Digital Pin Of WiFi Chip To Relay And Power Up The Relay By VCC And GND

enter image description here

Now By Connecting Wifi Chip To Users Mobile, Users Can Switch The High & Low In Digital Pin

And Thats Way You Can Control The Power Of Appliances By Users Control.

Jay Vadoliya
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