Arduino Fan Control Project

My RC buggy has a brushless LiPo system in it. It can get pretty hot when running bashing hard. The motor tops out at 190F and the battery should stay under 120F. The motor mount comes with 2 pre-drilled fan mounting places which is nice. However I didn't want to wire them in straight and have them run constantly because that would be inefficient and deplete the battery prematurely.

Charging the 6S battery pack on my HPI Vorza

So the solution (which also gives me another project) is to make a temperature control circuit for my Vorza. Having a background in electronics engineering this should be a fun and challenging project.

Here is the scope of the project:

• Temperature monitoring of the motor, battery, and inside the car body.
• Two high CFM fans. One mounted on the motor and one mounted on the car body. The fan on the car body will exhaust hot air created by the ESC and motor fans which gets trapped under the body.
• The fans will turn individually on when the motor and the interior of the RC body reach a TBD temp.
• The battery temp will be monitored and an alarm will sound with a specific series of beeps if it gets too close to over temp.
• The battery voltage will be monitored via the balance connector. A specific series of beeps will alert me of the charge level. 3 beeps for 75%, 2 beeps for 50$ 1 beep for 25%.
• There will be a 7 segment LED panel that will cycle through the temps and the battery voltage.

I plan to use an Arduino Mini Pro for the microprocessor, it's cheap and very small. It will fit into a socket on the circuit board so I can take it out easily for programming changes.

It has more I/O than the project requires, but like I said it's cheap (about $10). I'm designing a circuit board to mount the electronics necessary to switch the fans, measure the temps, and display the processed info. Here is what I have so far. It's a work in progress and I need to change out some of the components for SMD to make it more compact. 

Work In Progress

The circuit board hasn't had the traces routed yet, so disregard the rats nest of lines. I'm using Eagle CAD to design the circuit board. I'm using some fairly basic circuits. So far I have a voltage regulator circuit, 2 relay circuits to switch the fans and some sockets to plug the fans, TMP36 temp sensors and Arduino. 

I haven't figured out how to distribute the power yet. The sensors and Arduino are 5 volts, but the fans are 12 volts. If you have any experience with this please help me out with it.

I found some Sunon fans from Mouser that should be more than enough to keep the motor and interior cool.

The programming should be pretty straight forward, I already have the fan sensor/fan switching code written and working. The next trick is to add the beeps and LED panel code.  

Arduino Home Theater Control

Since I've just upgraded my home theater with a new TV and AVR I have obtained more remote controls. My remote control list includes:
LG Magic Remote
Marantz AVR Remote
Verizon Fios Remote
PS3/Apple TV Universal Remote

For various reasons that I won't go in to now, only one of the remotes are capable of eliminating the need for the other remotes. It sucks that we haven't moved forward enough to create an open standard for wifi control of consumer electronics. It seems like something like this would only benefit the market.

This problem is not new and if you have enough money and time, you can have a very nice control system. You could use Crestron, AMX, Control4, or any other number of vendors that offer iPhone/iPad integration or fancy touch panels.

Not me, I like to do things the hard way. Not to mention I already have all the components lying around.

My initial plan is to just use a simple push button to fire off a macro of IR commands to turn on and change inputs/modes to watch a movie.

That means:
Turning on the TV
Change the TV to the proper HDMI input
Turn on the AVR
Change the AVR to the proper HDMI input (more on this later)
Change the AVR to the proper surround sound mode

At that point I will have to use the AppleTV remote to pick a movie and so on.

It's not much of an advancement but should be a good place to start.

I've found several resources for Arduino code/libraries for this sort of project. I don't have much skill in the realm of coding so I will rely heavily on the web and a buddy of mine that has experience writing code for Arduino.

Here are two really good examples that got me started:
http://www.gamemaker.se/electronics/remote.php
http://www.righto.com/2009/08/multi-protocol-infrared-remote-library.html

So far, with this simple set up, I've been able to send basic IR commands to my LG TV. Off, On , Mute, Volume Up/Down, Input control.