Author Topic: Need information on how to control a microcontroller wirelessly  (Read 697 times)

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Offline Victor43Topic starter

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Need information on how to control a microcontroller wirelessly
« on: September 26, 2011, 01:10:13 AM »
Ok I am very new to the electronics terminology so please bear with me if I don't choose the right words. I would like to learn for just the sake of learning and to satisfy my curiosity on how experts like yourselves would carry out such a project. So what we have is say any device like an everyday fan (used to cool you on a hot summer day). Ok then how would someone add a say a component which would allow one to control that device (in this case being a fan) wirelessly ? Now I know that fans do come with a remote these days but this is besides the point (the device could be really anything like a Microwave, Radio, Central Air (thermostats), a portable heater and etc, anything else really). So if someone wanted to control the behavior of that device like our fan (make it turn on, off, higher speed, lower the speed) how can this be done ? How is it possible to add a new electronic component (a wireless receiver) to an existing circuit board that would allow someone to control this fan remotely (wirelessly) ? Please the fan was the only example that I could think of even though I know you can buy one with a remote control. I just want to understand how some one can carry out such a project.

Would you need to understand the existing datasheet of the existing controller to start off ? If so then how can you modify the existing circuit board to add a wireless receiver chip ? My only question is how can someone modify the existing design in order to accomplish what I asking about ? Do you replace an existing chip (of course one would need to understand the existing schematics) with your own that has the wireless receiver chip already built and ready to go ? To replace the existing chip would you not need to know how the existing Miicrocontroller works and its routines are in order to add extra features (like the ones being sent via wireless receiver ? s it fairly easy to have one of these microcontrollers with the embedded wireless receiver manufactured ? Are these Microcontrollers found on any electronic item fairly standard in the routines that they use ?

Thanks for taking the time to read this post. Hopefully I am have made my self clear but if not I would be more then happy to explain myself better.

« Last Edit: September 26, 2011, 01:18:58 AM by Victor43 »

Offline Gertlex

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Re: Need information on how to control a microcontroller wirelessly
« Reply #1 on: September 26, 2011, 12:16:38 PM »
The fan example is nice and simple, so I'll go with that.

There are two ways that I think of, right off:
-Use a "dumb" circuit to respond to a signal, e.g. IR signal like a TV remote outputs.
-Create a "smart" (and not nearly as cheap?) circuit via wireless serial port (e.g. Xbees) or bluetooth serial port

I've never really done the former, but I'll describe the latter process...

The fan is nice, because ultimately it's a motor with a power supply.  In the simplest case, you would have on/off.  I've never taken one apart, so I don't know for sure how the speed control/knob works.  I'm mostly a "combine major components" rather than a "build circuits" guy so that's how I'm approaching this. 

On the fan end, you would have a microcontroller (cheapest you can find, perhaps, since this is such a simple set of requirements), a motor driver (aka motor controller), and some method of remote control (xbee or bluetooth being most common option here).  These devices all need power for the logic circuits (e.g. 5 V from a regulator).  The fan's power supply and motor would be connected via the motor driver.  The motor driver regulates the speed and polarity of the power being sent to the fan motor.  The microcontroller in turn receives input from the xbee/bluetooth, interprets it, and sends the correct commands (actually just PWM signals) to the motor driver.

On your end, you'd have some sort of controller/remote to send the signals to the fan.  This could be a computer, or it could be a black box with buttons/knobs, another microcontroller to interpret button presses or knob positions; and the other end of the xbee/bluetooth connection.  Also a power supply (battery) for the microcontroller route.

With the components I'm familiar with, the xbee/bluetooth is probably the biggest cost (if you have a computer with bluetooth already, this is $20 or so... otherwise a range of > 30ft will need around $80 in stuff =-x ).  The two microcontrollers should be doable for less than $30 (maybe less than $20).  The motor driver would be something under $30, but I don't know how much current typical fans draw - higher current motor drivers = more $$.

There'd be a bit of software involved, too, but this would be pretty straight forward (imo) using Webbotlib.

Again, there's other ways and definitely some cheaper ways. I'm just good at solving problems with money, evidently.


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