Asked
— Edited

I have a Bluetooth speaker that runs on a lipo 3.3v battery. do I need a 3.3v regulator to run this speaker off of ez-b power? if so, could you recommend one?(looking for a specific name)
lm3940
You'll save around $1 at most by building the circuit yourself, if it works right away. For me it's better value to by a DC-DC converter pre-made.
Plus they work at very low drop out better then most dc-dc converters some will as low as 3.4 volts with 3.3 volts out.
What is means is that you battery will last much longer.
Look at the 3 pin 3.3 volt LDO that EZB uses super simple only 3 pins ,input,output and ground ,cant get more easy then that.
Some at a 4th pin for shutdown if it does just ground it.
PLUS should only need one cap at the output ,since the 5 volt regulator has one.
Spec sheet tells how easy to wire it up and pinout.
Another item about using it very tiny size compare to DC-DC CONVERTERS
i THINK the bluetooth speaker draws at least 500 ma if not more.
THAT link that ROBOT-DOC gave is 9-35 volts in at 3.3 volts out,so will need to hook it up to a higher battery supply.
And at 9 volts when the battery goes down some i wounder will it still regulate,(like about 7 volts)
whats good about the dc-dc converter is they are adjustable.
And in ebay search if you put in LM2596 you will see a lot of the same one at lower cost.
@Technopro just do a quick search on Ebay for LM2596 or voltage regulator and choose the one that fit your need. They are less than $5 including shipping. I also use
this one since it display the output voltage. most of them are like your h-bridge motor controller, can be solder or come with a cable.
www.ebay.ca/itm/5pcs-LM2596-1-23V-30V-DC-DC-Buck-Converter-Step-Down-Module-Power-Supply-/121106457242?pt=LH_DefaultDomain_0&hash=item1c3281e29a
Also, a further thought, if it is charged via USB you can just modify a USB cable and power from 5V since USB is 5V. It may be worth looking at that method (like DJ's method for the camera)
Edit: Big correction, the speaker has a 3.7v 450mah battery.
it's a delicate speaker so I need to wire it up to the correct voltage. if I use the regulator I found, it wont cause the ez-b to overheat, right?(in theory)
LiPo batteries come in 3.7v denominations. But fully charged are 4.2v. 3.7v when you should charge. Under 3.0v and it's ruined. Under 3.5v and it's being damaged. So with that in mind you can use anything from 3.3v to 4.2v without it being a problem. 3.7v is ideal though, 4.2v wont kill it. You could get lucky and try a 5v supply but it's at your own risk.
If you use a regulator I would advise connecting it to the battery not the EZ-B. No chance of it doing anything to the EZ-B in that case.
So you will not have a problem,i have a bluetooth speaker that uses USB input also,haven't had a chance to hook it up yet.
Reason is that you using a battery to charge a battery ,5 volt usb input charging 3.7 volt battery
So the solution is remove the battery and attach 2 wire to it from the regulator board and have the board adjusted at 3.7 .
They work great and are fully adjustable.
I did, as Rich says, connect to the battery and not the EZ Board.
Good luck with your build!
Second i would remove the 3.7 volt battery you don't want to charge a battery with another battery.
hope this helps you TECHNOPRO
@Technopro, stick with your last thought, the 3.7v to 4v regulator. 3.8v is probably the best voltage to set it to since this is the "official" rating of a LiPo cell. Although a week since your post I assume you may have tried this already? Have you had any luck or any further problems?
Don't forget to mark this one as solved once it is solved
RICH is correct on the official rating of the battery
BUT since the board is adjustable can set at 3.6 volts or 3.8 volts.
The old saying goes "better to be safe then sorry" so at 4 volt it may or may not hurt it
Everyone helped me out, and I thank everyone for that, but rich's responses answered the questions I had in the best understandable way. Thanks!