Hi olimex,check this out: https://www.kickstarter.com/projects/pnmini/pnmini-positive-negative-power-supply-module-for-m?ref=home_locationAlthough it is rated at 2A, but from their test data, it supports up to 3A for positive output, and 2.5A for negative output. Looks like a good fit for your project.https://www.dropbox.com/s/n4q602ssehkyu82/PNMini%20Datasheet.pdf
No, I wouldn't automatically think so. http://chrisgammell.com/switching-regulators-and-switching-noise/Depends on what you are doing.
Provide a different regulator or converter for the 5V high-current stuff. Keep highcurrent ground+supply wiring away from the Arduino or sensors.
Actually my problem remains the GSM Shield, it drains a lot and I don't know if it can be affected by an switching regulator
Quote from: olimex on Mar 21, 2014, 09:30 amActually my problem remains the GSM Shield, it drains a lot and I don't know if it can be affected by an switching regulatorGet a volt meter/amp meter combination, and put it between the power source and your Arduino to measure what the current draw is, and then you can use that in terms of sizing your voltage regulator.
Unfortunately that doesn't work for GSM shields. GSM transmits in timeslots (usuallyfor 1/8th of the time), so the peak current requirement of a GSM shield can be lotsmore than the average (which is all a multimeter will give you). You must read the datasheet for the shield and provide a supply that can give at least as much current as the maximum it lists. It can be several amps.
If it is several amps, you likely will need to get more serious about the batteries, than using plain multi-cell li-pos.
Its a possibility, but you need around 10,000uF which is a tad too large really.(for a max drop of 0.1V over a 577us timeslot at 2A).