Power question

Hi guys,

I just started testing out the Arduino platform. Very fun I must say :slight_smile: anyway I have not been able to find a simple and good solution to supplying power.

I will also add it is kind of a low budget project. So the solution cannot cost allot of $$$ Below 50$ I am aiming for.

Project will run leds, audio and servos for several weeks so I am thinking a wall outlet and not battery’s is the way to go?

E.g. 5 volt for the Arduino and 7.2 volt for the servo.

Are there power supply’s that output multiple voltage?

What are my options?

/Johan

Use one voltage and then convert that to the different voltages required.

EG, 12v for LEDS, and 5v for Arduino. Get a 12v supply and 5v switch mode converter for 5v.

Weedpharma

Thanks weedpharma,

So maybe something like this?

http://www.aliexpress.com/item/L155-Free-Shipping-DC-4-0-40-to-1-3-37V-LED-Voltmeter-Buck-Step-down/32320558392.html?spm=2114.01020208.3.148.IsHjRu&ws_ab_test=searchweb201556_3,searchweb201644_4_10001_10002_10005_10006_10003_10004_62,searchweb201560_1,searchweb1451318400_6150

Johan

And a power supply like this one

http://www.aliexpress.com/item/1Pcs-AC-DC-Adapter-Converter-DC-12V-5A-60W-Power-Supply-Charger-for-5050-5630-3528/32357549959.html?spm=2114.01020208.3.29.zG8xc5&ws_ab_test=searchweb201556_3,searchweb201644_4_10001_10002_10005_10006_10003_10004_62,searchweb201560_1,searchweb1451318400_6150

/Johan

I use LM7805 for 5vdc regulation, circuit is simple, I use the Kiwi Patch board to build power supplies (ignoring the "Picaxe 08M" comment) but these are easy enough to build up on a prototyping shield.

The supply and converter should be fine (assuming they are suitable for your load).

Using a LM7805 is not a good idea. The power loss bringing the voltage from 12v to 5v means the regulator will run hot. LM7805 is only really suitable for low current (when used at 12v) or for a lower input voltage of about 7.5v.

Weedpharma

Thanks guys!

/Johan

weedpharma:
The supply and converter should be fine (assuming they are suitable for your load).

Using a LM7805 is not a good idea. The power loss bringing the voltage from 12v to 5v means the regulator will run hot. LM7805 is only really suitable for low current (when used at 12v) or for a lower input voltage of about 7.5v.

Weedpharma

Interesting to note, I have never had an issue with these but typically I am only running the microprocessor ( up until now I have been using another type of hobbyist processor) and a few LED's and transistors to switch relays so very low power requirements.

D.C. to D.C. converters tend to be expensive down here, hence the building of low cost stepdown power supplies.

Is that servo rated for 7.2 volts? I only ask because most hobby-grade servos work on 4.8 to 6.0 volts. While there are servos designed to run on higher voltages, they aren't as common.

Kiwi_Bloke:
D.C. to D.C. converters tend to be expensive down here, hence the building of low cost stepdown power supplies.

The rest of the world has access to a thing called the Internet. Does it not work in Kiwi land? :slight_smile: :slight_smile: :slight_smile:

Weedpharma. (From the other side of the ditch)

I think it works with a input range. But as i undersand it it has maximum Torque at 7.2V

Size:402040.5(servo)
6455.620(Assembly the metal brackets size)
Weight:60g
Wire length:320mm
Speed: 0.16sec/60 degree at(6v)
0.14sec/60 degree at(7.2v)
Torque: 15kg.cm.at(6v)
17kg.cm.at(7.2v)
Voltage: 4.8v-8.4v

weedpharma:
The rest of the world has access to a thing called the Internet. Does it not work in Kiwi land? :slight_smile: :slight_smile: :slight_smile:

Weedpharma. (From the other side of the ditch)

It does, its great for looking up things like Rugby World Cup records, Bledisloe Cup holder etc. :slight_smile:

You could just hack a old used computer power supply, it has all the volts but the 7.5 but you could just use a resistor to drop it down from one of the 12VDC if the amp draw is not to high.

If you have a spare computer ATX power supply you can buy an ATX breakout board, or build your own.

I've got one of the Dangerous Prototypes ATX breakout boards, but there's a couple others out there. Plus tonnes of DIY

Laptop power supplies sometimes output ~19v with good current values. UBEC voltage regulators are good for voltage reduction to 5/6v.

Double check the particular laptop supply details of course - many are 19.5V nominal, designed to
charge 5 Li-ion batteries in series (I believe), but manufacturers do vary in their battery systems.

Also for a couple of amps step-down the LM2596 boards from eBay are priceless (I mean very cheap!), for instance:

http://www.ebay.co.uk/itm/LM2596-DC-DC-Switching-Adjustable-Step-Down-Voltage-Regulator-Converter-UK-/271995607118?var=&hash=item3f5433984e:m:mrSWUkPe83-Eb-dJMD-6hpw

(There are lots of suppliers, some even do one's with a voltmeter built in!)