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Electronic switch for external power

Discussion specific to the intelligent brick, sensors, motors, and more.

Electronic switch for external power

Postby achechin » 21 Apr 2013, 10:41

Dear All!
I am using Mindsensors 8 channel servo controller(http://mindsensors.com//index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=93) to run multiple servos. It required external 6 Volt power and I am using Mindsensors 4AA Battery Holder with NXT Mount (http://mindsensors.com//index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=147). On this holder there is on/off button. The idea is to replace the button to some sort of electronic switch to be able to turn power off from NXT when off servos are not required.

Would you please suggest me an idea how to implement it?

I thought about Mindsensors Relay Driver for NXT (http://mindsensors.com//index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=140) or PCF8591 set (http://mindsensors.com//index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=92).

Thanks and regards,
Alex
achechin
 
Posts: 8
Joined: 04 Nov 2012, 03:38

Re: Electronic switch for external power

Postby h-g-t » 21 Apr 2013, 12:37

You could connect a standard relay to a motor port.

Dual-relay versions specifically for LEGO are available - http://www.techno-stuff.com/relay.htm and - http://www.mindsensors.com/index.php?mo ... AGE_id=140

Latter advertised as a relay control but it is actually an electronic relay. Both models connect one set of 'contacts' with a 'motor forward' and the other with a 'motor reverse' signal.

Alternatively, you could use a 'latching relay'. These switch on with one power pulse and off with another. One type uses successive +ve pulses whereas another switches on with a +ve pulse and off with a -ve pulse. You could run two of the first type from one motor port using diodes to separate the voltage direction. Both have the advantage of not requiring power all the time.

All of these could also be driven from a sensor port using a PCF8574 - http://www.futurlec.com/Mini_PCF8574.shtml.
A sophistical rhetorician, inebriated with the exuberance of his own verbosity, and gifted with an egotistical imagination that can at all times command an interminable and inconsistent series of arguments to malign an opponent and to glorify himself.
h-g-t
 
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Re: Electronic switch for external power

Postby achechin » 22 Apr 2013, 10:00

All of these could also be driven from a sensor port using a PCF8574 - http://www.futurlec.com/Mini_PCF8574.shtml.


h-g-t, thank you for the answer. Could you please explain how power could be driven from PCF8574? I have several PCF8574 sets from Mindsensors so could use one of them instead of Mini board.
achechin
 
Posts: 8
Joined: 04 Nov 2012, 03:38

Re: Electronic switch for external power

Postby h-g-t » 22 Apr 2013, 12:04

You could use one of the motor ports.

http://www.philohome.com/nxtpwr/pwr.htm
A sophistical rhetorician, inebriated with the exuberance of his own verbosity, and gifted with an egotistical imagination that can at all times command an interminable and inconsistent series of arguments to malign an opponent and to glorify himself.
h-g-t
 
Posts: 548
Joined: 07 Jan 2011, 08:59
Location: Albania

Re: Electronic switch for external power

Postby h-g-t » 26 May 2013, 14:52

It so happens that I have some small latching relays which might be suitable for this sort of application.

Model number is ds1-ml-dc6v and you can get the data sheet here http://www.datasheetcatalog.com/datashe ... DC6V.shtml

On sale here http://www.babelduck.biz/product/sds-re ... -1-ml-dc6v for £0.99 plus shipping and taxes.

I would sell at 2 for £1.50 plus postage if anyone was interested.
A sophistical rhetorician, inebriated with the exuberance of his own verbosity, and gifted with an egotistical imagination that can at all times command an interminable and inconsistent series of arguments to malign an opponent and to glorify himself.
h-g-t
 
Posts: 548
Joined: 07 Jan 2011, 08:59
Location: Albania


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