Pages: 1 [2]   Go Down
Author Topic: Can I build a project using 4 AA batteries with a 5V Arduino board?  (Read 1787 times)
0 Members and 1 Guest are viewing this topic.
Global Moderator
Boston area, metrowest
Offline Offline
Brattain Member
*****
Karma: 524
Posts: 26420
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

I have  not done any testing Lefty. I don't have any of the new boards with the later regulator to try this with.

I do see that some of the arduino pages have this added now "Supplying voltage via the 5V or 3.3V pins bypasses the regulator, and can damage your board. We don't advise it. "

I was thinking perhaps connected but unpowered walwarts while powered from USB could be the culprit, but the reverse polarity protection diode should provide Vin isolation in that case.
Logged

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Left Coast, CA (USA)
Offline Offline
Brattain Member
*****
Karma: 361
Posts: 17262
Measurement changes behavior
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I have  not done any testing Lefty. I don't have any of the new boards with the later regulator to try this with.

Me neither.

I do see that some of the arduino pages have this added now "Supplying voltage via the 5V or 3.3V pins bypasses the regulator, and can damage your board. We don't advise it. "

Yes, I've seen that. I guess my question would be did they add that because of the recent change of voltage regulator or just because it's not a good engineering practice in general as I talked about below? Does anyone have a contact with a Arduino designer we could ask to find out their reason for posting that 'new' caution/recommendation?

I was thinking perhaps connected but unpowered walwarts while powered from USB could be the culprit, but the reverse polarity protection diode should provide Vin isolation in that case.

Yes, the Vin isolation diode would prevent any current flow from the board to anything connected to the external power connector, powered or off.
Lefty

Logged

Global Moderator
Boston area, metrowest
Offline Offline
Brattain Member
*****
Karma: 524
Posts: 26420
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Quote
PS:  And yes, like you my favourite way to power a standard arduino board with an external regulated +5vdc source is to take a spare USB cable, lop off the PC end and extract the power and ground wires and wire that to the external 5 vdc power supply.
I'd certainluy go along with that as a recommendation. The few times I use an actual arduino (as I usually have my own design going) I am powered via PC/USB cable for software download/test.
In my designs, I bring in 5V from a walwart to power the card. Or 12V if  LED strings are being powered, and use a 7805 regulator.
Or I bring in power via FTDI Basic for bootloading via MKii.
Logged

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Global Moderator
Boston area, metrowest
Offline Offline
Brattain Member
*****
Karma: 524
Posts: 26420
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Quote
Does anyone have a contact with a Arduino designer we could ask to find out their reason for posting that 'new' caution/recommendation?
I believe they did respond here a while ago, when the issue of bricked Mega's started coming up.
Logged

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Left Coast, CA (USA)
Offline Offline
Brattain Member
*****
Karma: 361
Posts: 17262
Measurement changes behavior
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Quote
Does anyone have a contact with a Arduino designer we could ask to find out their reason for posting that 'new' caution/recommendation?
I believe they did respond here a while ago, when the issue of bricked Mega's started coming up.

Did they state a reason?

Lefty
Logged

Pages: 1 [2]   Go Up
Jump to: