help with building compact radio

[TxBoy09]

I would like to build a radio in a waterproof pelican case. I will mount waterproof speakers on the lid of the box and use it on the river.

I have seen this done but did not look at what kind of amplifier or what other components i will need.

I will use a 12V battery out of a jump start/booster pack.

Can anyone help me with what type of amplifier will work for me so that I can hook my ipod up to it, then control the volume from the outside of the box?

Thanks,
Brandon

 

[55pilot]

Are you looking to build a radio or an amplifier for an ipod?

If it is an amplifier for an ipod, how are you going to waterproof the ipod if you leave it outside the case?

---55p

 

[TxBoy09]

i apologize...it will not be a radio...it will play music from the ipod...

My intentions are to leave the ipod inside the case....but i would like to have a volume knob that will stick out of a hole in the box...assuming that i can find a waterproof knob

Any suggestions on where I can buy the small amplifier?

 

[55pilot]

There is one more critical issue that you need to decide early one. Do you want this thing to be waterproof as in "dunk it into water is OK" or do you want it to be water tolerant where it does not mind getting wet, but will get into trouble if it is submerged? Water tolerant is a lot easier than waterproof.

I am not familiar with waterproof speakers. A quick google search suggests that they are the "don't mind getting wet" type and not really waterproof. You will have to cut a hole in the box and mount them with appropriate gaskets etc to make sure the box is not flooded.

You can buy any old portable ipod amplified speaker and take out the amplifier from it. Or you can do a google search for "audio amplifier" and get dozens of hits. You will need to do the wiring for the battery and the ipod connector. You may need a power supply board to get the 12V battery to a lower voltage. You can buy or build that depending upon your level of knowledge and ability. But I suspect you should not have a problem getting an amplifier that runs directly off a car battery.

Getting a pot to be waterproof or even water tolerant is not an easy task. There are audio pots available that have environmental seals in them. They are not cheap or easily available. You can mount one of those through the box. You would be better off finding an audio amplifier that has "volume up" and "volume down" buttons rather than a pot. That makes life a lot easier because it is much simpler to have a waterproof push button switch.

You need to be really careful about mounting and securing the battery. If there is a shock, you do not want the battery to come loose and touch something that shorts its terminals. That could result in a fire or maybe even an explosion, which is never good.

I am sure others will have other ideas or more specific recommendations.

---55p

 

[(*steve*)]

One option is to mount a speaker inside the case so that it vibrates the case -- generally speaking you'll need to cause the piston action of the speaker to deform the case -- possibly by pressing the speaker against the case and sealing it. Naturally you'll want to do this without putting holes in the case.

You *might* be able to wire up some touch switches to increase and decrease the volume.

With controls like that your system would be a watertight as a pelican case. Whether it would sound any good is another issue.

I have visions of you watching forlornly as your case, still playing your favourite music, floats slowly toward a waterfall...