MP3 control Hack using a motion sensor and a Microcontroller
   
   
Using a microcontroller is not as hard as you might think. For an introduction to microcontrollers please click the Microcontroller 101 link below. I would like to thank Otaku and Bourno for the information on the work they did for there MP3 Hacks. There web links are here.

Otaku's MP3 Hack
Bourno's MP3 Hack
   
Microcontrollers 101    
   
Now do not run screaming to the door. The picaxe microcontroller is very easy to use. I have been using them for several years now and they have really helped me take my prop control to another level.  They program is basic just like a basic stamp but cost about a tenth the price. The software and the manuals are free. If you do not know anything about electronics do not worry there is a lot of information available to help you look in the links section for a free online electronics course. Send me an email and I can help you get started with electronics or microcontrollers. In this How-to I used a picaxe 08M (about $3.50) to control the now infamous 5 dollar MP3 player. I am also using the parallax motion sensor to trigger it. The picture below is the actual circuit that I made on a prototype board. With this chip I can control the start, pause, and stop functions. You can start the player have it play for a long as you like, also you can pause it as many times as you like and then shut it down until the next trigger in order to save battery power.





This picture below is how it is connected to the MP3 player. The red and black wires sticking up from the circuit board is the negative and positive battery connections for the circuit board. The gray wire is soldered to the switch in the MP3 player. I have also tapped off the battery connection inside the MP3 Carrier so that I can use a larger battery. Even though there are two batteries in the holder they are both facing the same direction so it is still 1.5 volts. The batteries are in parallel.





Here is the circuit schematic and how to connect the MP3 player to the circuit. The Picaxe 08M has 5 pins that can be used as inputs or outputs. The pins are labeled 0 to 4. The pins do not match with the chip pin number (this is common of all microcontrollers). For example output pin 1 is pin 6 of the chip. Keep this in mind when you read the schematic so that you do not get confused. The output pins 1 to 4 are labeled. Pin 0 is also used for programming the chip. I try not to use output 0 unless I have to. There are many other larger picaxe chips all the way up to 40 pin units. Everything to the right of the chip is for programming except the cap which is to keep the chip stable. Just 2 resistors are needed to program the chip and a 3 pin header. The circuit for the programming cable is there as well as a 7805 regulator circuit if you want to use a wall wart. Input 1 is connected to the other 3 pin header which connects to the Parallax motion sensor. The 220 ohm resistor is to protect the chip input from over current. Output 2 is connected to a NPN transistor through a 1K resistor to limit the current on the transistor base. The transistor shorts the MP3 player switch to ground effectively pushing the button.   The program for the chip can be seen here.
   

 MP3 control program with motion detection    








I forgot to take a picture of the solder point inside the MP3 player so I borrowed a picture from Bourno's web page. the point indicated in the picture is the exact same spot that I used.






   
Go to page 2 to see the Motion sensor and board mounting --