I am working on a sculpture that includes three servos, 4 x 12v motors, and 30 LED's. The three servos are running well on a 6v/1.5 amp wall wart. The additional three motors (12v, 500 mA each) will be ready for testing in a few day. Ideally, I would like to use a single power supply for the entire project. Something ready made wold be great but I see no Wall Wart rated more than 2 Amp. Is there something salvageable? If not, do I have to order a transformer, rectify it from scratch? If the total is 5 amps, do I make a rail and regulate with 78-- or LM317?
A 78-- or LM317 are for 1A or a little more and they get hot, you might need a heatsink.
A DC-DC converter is very efficient.
Do you use an Arduino and a motor driver ?
If the servos are 6V, you could use a DC-DC converter to 6V and use it for the adapter plug (or Vin) of the Arduino and the servos.
If you can power the leds with 12V or a with second DC-DC converter, you would only need a power supply of 12V.
Are the DC to DC converters you describe the same as "buck converters? I am looking at tutorials to understand your suggestion. Are these circuits or a single component?
ifugaopapercraft:
Are the DC to DC converters you describe the same as "buck converters? I am looking at tutorials to understand your suggestion. Are these circuits or a single component?
DC-DC converters is a common name for step-up, step-down, boost and buck-boost converters.
Sometimes it is a small black box (with the components inside), but mostly it is a circuit board.
Some examples: dc dc converter for sale | eBay
To be sure I understand; I could use this AC / DC Adapter For Nakto 48V Battery Electric Bike Mountain eBike Power Supply | eBay and regulate with two or three of these DC to DC 5pcs DC DC Buck Converter Step Down Module LM2596 Power Supply Output 1 23V 30V for sale | eBay?
The second one (DC-DC Buck converter) is okay. If 2A is okay for you.
I have doubts about the first one (switching power supply 12Volt 5 Amp). I bought a few switching power supplies from Ebay, and most of them can not deliver the current and they get overheated and get broken within a few month.
If you would also use a DC-DC converters for the motors, you don't need a regulated power supply. Perhaps you have some DC power supply already ? Or an adaptor of 19V for a laptop.
So if the total amps is around 5, what should I use for a power supply? Hopefully, something I could find at Goodwill?
Did you look at mpja.com at all?
They have high current suppllies available.
You could use a 12V, 4A supply and use smaller switching adapters for the lower voltages
Pololu - Regulators and Power Supplies
Or would this be better? LCD (12v 5a) AC Power Supply Adapter DC 12 Volt 5 Amp 60w for sale online | eBay
The first one depends on the motors. For an unregulated power supply I would prefer to use 15...25 V, and use DC-DC converters to make a good 12V for the motors.
The second one is a brandless cheap switching power adapter again. If you buy that, you probably have to buy a better version soon. Don't try to buy a good 12V 4A power supply for 10 dollars, that's not possible.
If you want something cheap, this one: http://www.mpja.com/12-Volt-Power-Supply-85A-100W-Switching-Hengfu/productinfo/16013%20PS/
But I'm not sure how it will behave without any load.
If you want something better: http://www.mpja.com/12-Volt-Power-Supply-51A-Linear-IHN12-51/productinfo/6609%20PS/
Sorry, a dumb question: What happens to the unused amps? Any problem running these motors directly from the power supply? Can both current and voltage be adjusted? I have ordered DC to DC converters. Thank you so much for the advice. The typical small, Arduino board driven projects I have worked with before have not been so challenging in terms of power supply.