Crazy big project

Hi everyone.

Newbie here. Since I was able to make my first project a success (still working on part 2 of it), I would like to keep going.

Although mear size of this is scary to me.

I would like to make an interactive device that does all of the following, in steps (versions). Can you recommend which modules to use and if I will be able to do everything in one device below?

Rules: Must be battery powered, rechargeable.

Version 1: 1. using flex switches, it triggers specific mp3's to play. 2. Lights RGB LEDS and changes color with the music. 3. It listens to background sounds, if the sounds are loud enough, it triggers an mp3 and the RGB shines a specific color.

Update 2: 1. Can recognize its name (hopefully by a few different voices), triggers mp3 and RGB LEDs

Update 3: 1. Accelerometer detects when it is swiftly moved, triggers mp3 and RGB LED

Update 4: 1. RFID Integration: plays specific MP3's and RGB LED based on rfid token.

Update 5: 1. GPS Integration: checks every set period of time to see its location. If within a specific region, it triggers an MP3 and RGB LED. If entering a different region, it triggers a different mp3.

What do you think? Is all of that possible for one device by a newbie as long as I go in small stages listed above? If all good, how do you recommend I start on version 1? Which hardware do you think I should order from sparkfun or other electronics site?

ALSO I am going to create a blog update every step of this project and what exactly this mysterious device will be! :)

Thank you!!!! :) Cant wait, just bought another Uno just for this project so I dont have to tear down my other project.

Number 2 could be possible with something like this: You'd just get different people to say the same thing as different 'words' on the device. If you fill up all of the 32 triggers with different people saying it, it should be able to pick up the single word/phrase pretty well.

The battery life bit will be a problem - can you just attach it to a car battery? That's rechargeable and a battery...


Thank you for the reply.

1) Exactly what do you mean by "flex switch"? Please cite an example. How are they actuated? 1a) How many of these switchtes? 2) How many RGB LEDs? How big/bright? 3) One MP3 or many? 4) How big is your proposed gadget? How long do you want for battery life?

1.) I found these at sparkfun: I am hoping that embedded into something like a pillow, if squeezed it will trigger on the Arduino. 1.a.) 2-3 2.) I wanted a handful, but as I am researching battery power, it might have to be just a few. Maybe 3 or 4, small, but bright enough to shine through the skin of the pillow? 3.) Many MP3's, I found this on sparkfun which gives me 18 triggers: 4.) As small as I can get it. I would like battery life to last as long as possible, a full day if possible. It wont be triggered throughout the day.

Hi mowcius,

I saw that on sparkfun. Looks great! And I think you are right, if we all program a separate trigger saying the same thing, it is bound to pick it up.

However the battery issue is a big one. Cant be a car battery. More like 6 rechargeable AA. or a small 12v rechargeable.

but bright enough to shine through the skin of the pillow?

Have you just given it away? :D

The mp3s could be done with something smaller and cheaper than that board - you have a microcontroller in this thing so you don't need digital triggers, you can just tell the module (whichever one you get) to play the mp3. You're also going to need speakers & possibly an amp circuit depending on how loud you need the audio (and how large the speakers can be).

Battery is going to be a problem. People don't think of it initially so it often catches people out. Ideally you want something that's at 5V or something like some lithium packs with a boost converter making it 5V.

I'm not saying the voice recognition will work, if you have a lot of different people record triggers then it may start to pick up other words from different people, confusing them with what someone else has said.

What requirements do you need for flex sensors? Flat surface? Flexing in more than one direction?

I have an arduino, but willing to get a different one. I would love to use something that didnt have the same price as that board. I am on a limited budget. But on the other hand, I am such a newbie, I figured it would be the easiest. Is this where that book "making things talk" comes into handy? Havent read that one yet.

The MP3's playing will be spoken voice and maybe some music following the voice on the same track.

The speaker can be a cheap speaker, doesnt have to be too loud, just loud enough to hear from 2-3 feet away.

For Power I bet I could use those 3.7v lithium batteries. They last a long time, 900 mah. And if I am not using that board I will be saving power.

Imagine 3 flex sensors from, embedded into a pillow, one on the right, one in the middle and one on the left. If you were handling this pillow and you hugged it, I would want one of the sensors to trigger the arduino telling it which sensor was triggered. Therefore the arduino would play the mp3 designated to that sensor. Example the left one. "Hello, you have just pressed the left flex sensor". Is there a better alternative to the flex sensor?

Thank you so much.

  • I meant Arduino Uno. Sorry.

Hmm, well firstly with limited space and as something you don't want to spike you when you squish it, you want to go with something smaller than an arduino uno.

For the audio, if it's going to be through a cheap speaker then quality doesn't need to be fantastic presumably - perhaps a device which plays .wav files rather than .mp3

The lithium ion batteries are probably a pretty good bet, with some careful power consideration a 900mA could last a day (depending on how many times the device is played.

The flex sensors are a bit of an issue, perhaps something like this would be more suitable - could be sewn in and can flex in any direction but if the whole of the 'device' was compressed then it would not really be 'flexing' anyway which could be a problem.


That could possibly work. Only issue is I would have to cut out any music or long speech since it is capped at 64 seconds. Unless I can ad an SD card to it.

I am doing a RBBB next time for sure, or one of the mini's as soon as I get the hang of this. I could always use one of my 2 UNO's to programe the chip right?


I dont think quality will matter as long as it is understandable.

I agree with you on the flex sensors. In fact they are not rated real well on their reviews either. I like your suggestion, I have never seen anything like that before. Great find.

Question, if we avoided the mp3 trigger shield, and went the Arduino route, how or where do you think I should look to learn how to build one?

Thank you!

Well there are MP3 playing modules which are very similar but normally smaller and cheaper as they just have a data interface rather than lots of connections for digital input triggers.

With regards to the flex sensing, you'll have to think carefully about how you can mount them so they will be able to detect enough flex when the device is squished.