Comments for The Handy Board

Comment on What is the difference between a DC motor and servo motor? by waqasalijoya

waqasalijoya — Sat, 13 Aug 2011 04:59:33 +0000

very informative. thanks

Comment on Hardware FAQs by sarvatxo

sarvatxo — Thu, 02 Jun 2011 17:19:49 +0000

How can I connect an I2C device to handy Board? Can I connect it directly or maybe should I use an I2C to serial interface like the BL233? Thanks.

Comment on Purchase by fredm

fredm — Mon, 30 May 2011 17:00:07 +0000

Yes, the DC motor outputs can drive relay coils. Just make sure to use full-power motor commands, or otherwise the pulse-width modulation will be bad for the relay coil.

Comment on Purchase by profco

profco — Mon, 30 May 2011 16:50:08 +0000

Thanks Fredman!

I have a question:
can I connect releys to the HandyBoard ?
to handle high-voltage motors.

thank you very much for the information.

Comment on Purchase by fredm

fredm — Mon, 30 May 2011 12:37:38 +0000

Why don’t you email to each of them and ask their shipping policies and costs?

Comment on Purchase by profco

profco — Sat, 28 May 2011 09:58:53 +0000

Hello,

I want to buy a Handy Board, I live in Madrid Spain, I saw the list of authorized dealers, but none are in Europe.

which vendor would you recommend?

thank you very much for the information.

Comment on Hardware by fredm

fredm — Tue, 26 Apr 2011 14:36:13 +0000

Nominal battery voltage under load is 9.6v. Diode drop is closer to 0.65v.

Comment on Hardware by infiniteloop

infiniteloop — Tue, 26 Apr 2011 14:21:37 +0000

What about when the battery is fully charged? The battery voltage can be more than 10v when fully charged. 10-(.6*5)=7

Am I missing something?

Comment on Hardware by fredm

fredm — Tue, 26 Apr 2011 13:56:50 +0000

When there is a load, the voltage will drop; diodes have a characteristic 0.6v drop under load (e.g., 100 mA or more). The circuit actually has a flaw that unloaded, there is no voltage drop. Some servo motors (particularly, the micro sized ones) can get burned out by the overvoltage. Regular sized servos are fine though, and once the servo starts drawing current, you will see the voltage drop to the intended level (5 to 6v).

Comment on Hardware by infiniteloop

infiniteloop — Tue, 26 Apr 2011 13:53:03 +0000

As an undergraduate studying Electrical and Computer Engineering, I am interested in how some of the handy board electronics work. I looked at the schematic for the expansion board, but I was unable to understand how the diode chain regulates the servo voltage, especially as the battery voltage varies with charge level.

I also probed the voltage on the servo ports with a voltmeter, and instead of getting 6v, I was getting 10v. This measurement was taken while the expansion board was powering a Futaba S3003.

Can you explain to me how this works?