Hi all-
I wanted to make a "mobile" which is basically a spinning device that plays music on a crib for my new son. You can buy ones for $50 but they suck, so I thought I'd make a cool one. However, I ran into some electronic problems and was looking for some help.
Here's the plan:
1) Have a toy 12V motor power the spinning rocket ships I tend to attach to the motor. Power the 12V DC motor with a 12V AC-DC converter. This was a snap.
Here's the problem...it spins WAY too fast. So I was wondering, in order to slow it down, should I put a resistor or variable potentiometer in front of it? I know in theory this would reduce both the current and the voltage across the motor (slowing it down???). Or is there a better way to do it?
2) Have an old portable MP3 player play the music. It has a 1.5V battery. I soldered terminals onto the battery leads and attached them to a 1.5V DC current. It ran fine. The problem is I'd like the whole thing to be powered by one power source. So in parallel, I need to change the 12V from the AC-DC converter to 1.5V only across the mp3 player and NOT across the 12V motor. I discovered I needed a DC-DC converter for the second parallel circuit. The problem is, at Fry's and Radioshack the only DC-DC converters they sell are for Cars and they are enormous. Does anyone know where to buy a small-low voltage 12V-1.5V DC-DC converter or how to make one that's reasonably small and not terribly expensive?
3) play the mp3 through a small 2-1/4" 8 Ohm speaker. So I bought a mini-jack plug and soldered the terminals of the speaker onto it. I can hear faint music when I crank the MP3 player to the maximum but it needs to be louder. The trouble is that it was meant only for headphones. How do I amplify the signal from the MP3 player before it reaches the speaker...preferrably also using the same 12V DC source.?
Is any of this possible?
Any help would be appreciated including links to resources on how I can solve these problems myself. I've been searching the internet for information but I can't seem to find where I can buy some of these things such as a small-low cost DC-DC converter or small speaker amplifier or how to make them. I unfortunately majored in Biology in college which really doesn't help here =)
Thanks again for all your help.
Vik
I wanted to make a "mobile" which is basically a spinning device that plays music on a crib for my new son. You can buy ones for $50 but they suck, so I thought I'd make a cool one. However, I ran into some electronic problems and was looking for some help.
Here's the plan:
1) Have a toy 12V motor power the spinning rocket ships I tend to attach to the motor. Power the 12V DC motor with a 12V AC-DC converter. This was a snap.
Here's the problem...it spins WAY too fast. So I was wondering, in order to slow it down, should I put a resistor or variable potentiometer in front of it? I know in theory this would reduce both the current and the voltage across the motor (slowing it down???). Or is there a better way to do it?
2) Have an old portable MP3 player play the music. It has a 1.5V battery. I soldered terminals onto the battery leads and attached them to a 1.5V DC current. It ran fine. The problem is I'd like the whole thing to be powered by one power source. So in parallel, I need to change the 12V from the AC-DC converter to 1.5V only across the mp3 player and NOT across the 12V motor. I discovered I needed a DC-DC converter for the second parallel circuit. The problem is, at Fry's and Radioshack the only DC-DC converters they sell are for Cars and they are enormous. Does anyone know where to buy a small-low voltage 12V-1.5V DC-DC converter or how to make one that's reasonably small and not terribly expensive?
3) play the mp3 through a small 2-1/4" 8 Ohm speaker. So I bought a mini-jack plug and soldered the terminals of the speaker onto it. I can hear faint music when I crank the MP3 player to the maximum but it needs to be louder. The trouble is that it was meant only for headphones. How do I amplify the signal from the MP3 player before it reaches the speaker...preferrably also using the same 12V DC source.?
Is any of this possible?
Any help would be appreciated including links to resources on how I can solve these problems myself. I've been searching the internet for information but I can't seem to find where I can buy some of these things such as a small-low cost DC-DC converter or small speaker amplifier or how to make them. I unfortunately majored in Biology in college which really doesn't help here =)
Thanks again for all your help.
Vik