using ipod touch to control relays

scott_fx · 03-15-2009, 06:14 PM

Hey guys,

it's been a while since i've been around but i have a new project i want to get started. basically i want to use an ipod touch as a very simple media player on a boat... simple enough. the other thing i want to do is control a ballast system (6 pumps) using the ipod. Are there any applications/hardware that will let me do something like this? My initial idea was to use fusion brain but i'd love to stream line this to an ipod and one other piece of hardware to do the switching as well as having a small display that i can incorporate into the limited space on the dash.

thanks in advance,

scott

scott_fx · 03-15-2009, 07:38 PM

so i think i figured something out. i'm going to use this thread as a brainstorming thread so please, any constructive input will be appreciated.

so to do this i'm going to need a few things:

control interface:
ipod touch

relay board:
infrared remote relay board
or build it myself:
simerec's sis-7c ic
less expensive sony chip with 14 latching outputs

transmitter to be hooked up to the ipod touch:
transmitter

reciever to be hooked up to your computer in order to record the ir signal:
simerec's ir-w
or
38kHz Infrared (IR) Receiver Module

receiver schematics 1
or
receiver schematics 2

use the following documentation to convert wav files into ir 'commands':
use ipod as a remote

now onto the software side of things and seeing how hard it would be to make an application that can play the sounds based on button presses on the ipod touch. again, any help would be greatly appreciated.

the one issue i see here is how to hook up the ipod to the stereo as well as the ir transmitter. I could hook them both up with a toggle switch but there has to be a cleaner way.

more research that is way over my head:
more research that is way over my head
this looks promising but i think you need web access

i'm going to keep updating this post for future developers... most of what i add here is way out of my scope of hacking, so enjoy:
useful development boards for the ipod

Shabaz · 03-16-2009, 12:25 PM

Hiya,

Not read it totally in detail, but you could record a 'command' which is
a high frequency (say 19.5kHz) burst of 50-100msec and a 50-100msec pause, and then repeat a few times. This could be followed by a DTMF tone, which is easily decodable (there are ICs which do this).
The high frequency bursts would be used for detection by a microcontroller, to briefly mute the audio to the amp, so that the subsequent DTMF is not played over the speakers.
The 19.5kHz would not be audible across the speakers, because it is too high (but the line out from the ipod will easily create this frequency, so it is detectable by a circuit).

There are probably other ways of doing this

this was just one idea that came to mind.

scott_fx · 03-16-2009, 12:31 PM

you know... you just gave me a great idea. i wonder if i take ir the commands that are recorded by the computer, alter them so they are above 18khz and then make a simple x-over to filter out anything below 18k and pipe that to the ir transmitter... hmmm...

if it works it won't need the micro controller and should be inaudible/undetectable/uninterrupted

Bugbyte · 03-16-2009, 12:47 PM

To change radio frequencies the original Griffin iTunes FM modulator used a series of high pitched beeps that sounded like very fast Morse code, a space of about 2 seconds and then a final 'confirmation' beep that must have been programmed into the modulator.

Each packet of beeps corresponded to an iTunes music track. You'd select artist Griffin and album Frequencies and every FM frequency would show up as a song. You'd scroll to select the frequency you wanted to transmit on and play it. Then, it would play the beeps and switch the fm modulation to that frequency.

I always thought it was a pretty slick solution to the issue of having no way to interface with the device. Later on, they put a small LCD screen on it and I don't think you had to do that anymore.

rodweb · 03-16-2009, 10:56 PM

You seem to know what you are doing, so have a look at the Arduino an open source embedded controller that you program in C. See www.arduino.cc. There is an example on the Arduino playground of controlling an Ipod using opto isolators soldered onto the Ipod buttons. There is also a library for it to control an LCD display so you could mount a 2 or 4 line LCD in your dash. There are motor controller circuits for it as well.

I've had one for a fortnight or so and they are simply amazing. I think it will do everything you want to do and more. There is a bit of preliminary detail on my worklog about the Arduino.(see my signature)

scott_fx · 03-16-2009, 11:00 PM

thanks, i checked out the arduino (i think i linked it too) but i can't code

I'll research it a bit more.
if you realize, most of my ideas are hacks and smashes of other people ideas

when i get home i'll check out your build, i'm very interested!!

rodweb · 03-16-2009, 11:04 PM

Never too late to learn, you just got to learn how to hack other people's code now

scott_fx · 03-16-2009, 11:08 PM

haha... ok ok... i'll take another look at it... it'll probably blow my budget though!

rodweb · 03-16-2009, 11:21 PM

Here, I'll help:

Ipod control: http://www.jonasolson.se/content/arduino_tutorial/

Triggering relays: http://www.arduino.cc/playground/upl...ain/relays.pdf
but using the solid state relays I used is easier

rodweb · 03-16-2009, 11:25 PM

Sorry, I hit enter prematurely in the post above. The relays will turn your pumps on... the SSR's I use hande 2 amps at up to 50 volts if your pumps draw more than that, trigger a heavier current relay with the SSR.

Of course the LCD now:

http://www.arduino.cc/playground/Code/LCD

Not sure if it is feasible to get the track info from he Ipod, but there is a USB port on board.

scott_fx · 03-17-2009, 12:45 AM

thanks for the link. i think this is getting a bit away from my original concept though. If there was a way that the ipod could interface with the arduino then i think it would be more attractive. The nice thing about the ipod touch is the compact touchscreen. a used ipod touch is about $150 and the components for the rest of the hardware (relay switch board, ir hardware, etc...) will probably cost me under $50. The primary function will be to play music with the ability to control the ballast system. With the arduino board; if i factor in the board, the lcd touchscreen (which is smaller then the ipod touch) and then the relay components... i think i'm looking at more then $400 ($200 for the board and $200 for the screen) plus having to have another device for music and not having it be as friendly as the ipod's music browser. At that point it may be worth while to go with the fusionbrain, fanless via board and a touchscreen.

edit... i dont know what i was looking at but i guess the arduino board is 30 bucks?

now if the link i posted above:
http://www.youtube.com/watch?v=Di8uIf22ufc
didn't require a pc to have the ipod talk to the arduino board... then we'd be in business

rodweb · 03-17-2009, 02:34 AM

Not as far from your concept as you think.

The only thing the Arduino is getting from the PC in that picture would be 5 volt power, but the great thing is that there is also a power socket on board so you can feed 12 volt power (well actually 9-20 volts) into it so you are in business. If you use external power, you only need to use the USB if you want to send data to and from a PC while the Arduino is running and to download programs (called sketches) after you compile them.

As for the LCD screen, I think you are on the wrong track, they are only $13.95 see here: http://www.sparkfun.com/commerce/pro...roducts_id=255

You should be able to source the SS relays for under USD $10 each. (I paid AUD $12 which is about USD $8 each)

And the Arduino itself is only $29.95. This is the one I purchased:
http://www.sparkfun.com/commerce/pro...roducts_id=666

Here is an example of Ipod control over USB

http://www.arduino.cc/cgi-bin/yabb2/...1233793991/5#5

So you only got to find some code that guy with in your link used to do it th eother way via wireless.

Should not cost you more than $100 to do this.

scott_fx · 03-17-2009, 02:39 AM

sorry for my ignorance... but, the ipod is controlling the arduino directly? I was under the assumption that the ipod was connecting to the laptop and the laptop was controlling the arduino.

oh.. and about the lcd screen... i was under the impression that you were tellilng me to scrap the ipod and use the arduino board exclusively... that's where i got the ~$200 for the arduino stealth touchscreen:
http://www.liquidware.com/shop/show/...chShield+Slide

rodweb · 03-17-2009, 02:57 AM

You may be right when I look at the video again as I don't see any sensing components on the breadboard. I don't know anything about the Ipod Touch, but it might be worth searching for the Ipod Accessory Protocol
http://www.ipodlinux.org/wiki/Apple_Accessory_Protocol

This must be wat the Alpines and my Sony stero with the Ipod cradle use to talk to the Ipod.

This may allow you to use some momentary touch buttons and maybe a rotary encoder to control the Ipod from the Arduino which would not be too bad really, particularly if you could get back the track name that is playing and display it on the LCD. You would have the added advantage of powering the Ipod so you don't run out of music....

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