For what it is worth, you may get better battery life using a buck regulator, as they are more efficient, something like an LM2596, which you can get as a module...
Hi there, yes the voltage regulator is very inefficient. That's why I went to the http://www.ti.com/product/ptn78060w because it is a bucking/switching power regulator. From the site: High Efficiency (Up to 96%). The LM7303 I had was not efficient at all and in fact got very hot, but it worked. Once I get a 12v gel cell for this setup, I should be able to take photos for days on end 
BTW that one with the blinkenlites is pretty cool! +1 for blinkenlites
Just a few notes for anybody else following this topic.
Theory.The "blinknlites" version uses the
LM2596 which should according to the datasheet be able to push out 3A at 3.3V (you may need an additional heatsink to push it any harder than 2A according to some sources, but that would most probably only be true for higher output voltages), so it should be able to cope with any of the CHDK capable cameras.
When setting up, I would use a dummy load across the output to set the voltage. Something as simple as a 100 Ohm 1/2Watt resistor should do the trick (they only cost a few pennies). ( I=V/R so that should draw I=3.3/100 or about 33mA which should be fine for adjusting the voltage on load).
The input voltage (for the versions of board I checked) should be a minimum of 2V more than the output voltage, and shouldn't exceed the maximum rating on the suppliers spec, or the maximum in the TI spec if the supplier doesn't make this clear (35V DC seems to be safe maximum value for most designs with this regulator, so you should be able to power your camera from that old Dell laptop power supply that is gathering dust in the cupboard(19V DC at 4A), or hook it up to a car battery (around 13,2V and lots of amps) with little fear of damage, of you are careful when setting things up.
Some boards state the input voltage can be less than the output voltage, and while this is theoretically possible, I suspect that the board is not actually configured to allow this, your mileage may vary of course as there are several different designs out there.
Setting up.Adjusting the voltage with the camera connected would be a bit risky.
If you opt for the non blinkenlites version, you will of course need a DC volt meter or multimeter to set things up.
When using with an Ixus or Powershot A series and a dummy battery I would start with the voltage set for 3.3V, if this proves unreliable, maybe push it up to about 3.7v (or whatever figure is quoted on the Canon battery).
For other cameras (those that use AA or AAA cells), Adjust the output to the voltage stated on the Canon accessory power supply for your particular model (assuming you are plugging in to the DC power socket on the camera, and not using a dummy battery). Google for that voltage, and go with the figures quoted on the Canon web site, as some of the cheap clone power supplies are a little on the unreliable side, both in terms of electrical safety, and written specifications an the supplier's web pages. If you are using some sort of dummy AA cell replacement, adjust for the voltage of the appropriate number of AA or AAA cells. Assume between 1.2V and 1.5V per cell, so for two AA cell, adjust to 2.4V and push up to no more than 3V if this is unreliable.
SafetyWhile the voltages we are dealing with here are relatively low and therefore fairly safe, the currents (and therefore the power output) can lead to some problems, insulate everything well and don't be tempted to try connecting this contraption up directly to your LiPo battery to charge it... It may kinda work, but it may also kinda blow up the battery spectacularly.
One more word of caution, once set up, if you don't have the LED voltmeter of the 'blinkenlights" version, and you have more than one camera, label your creation with its output voltage, and the camera it should be used with so you don't accidentally connect it to the wrong camera.
If in doubt about what voltage to try, start by adjusting to the voltage shown in the CHDK battery indicator when running on a fully charged battery, and only increase (in small increments) if this proves unreliably low.
In everyday use, I would recommend an in line quick blow 3A fuse on both the input and the output to protect both the camera and the regulator. The same precaution is justified for any of these buck regulator modules, as shorting out the input battery pack without any protection can lead to thermal runaway and some very interesting smoke signals
.
From memory the Ixus 60 has an internal
2A SMD fuse, so perhaps even a 1.8A external fuse on the regulator output would be wiser, fuses are much cheaper than zapped cameras and exploding batteries after all.
Now I just need to put my money where my mouth is and rig a couple of these up and post the results
