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 Robotics / RCX / 227
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Subject: 
Re: RCX motor voltage
Newsgroups: 
lugnet.robotics.rcx
Date: 
Tue, 9 Nov 1999 03:31:43 GMT
Viewed: 
1536 times
  
Terry King wrote:

Wes, relays would work pretty well.

(Still, how much current do your motors draw???) The
LEGO motors draw about .35 Amps (350 Milliamperes)

I am using the motors that came with the RCX.

You could connect two 5V coil relays , each with a diode in series with
the coil, connected oppositely to each other. The nominal 7 volts
or so from the RCX, minus about .7V across the diode would be
pretty close.  "Forward" would operate one relay, "Reverse"
would operate the other, and Off or Float would turn BOTH
relays off.  THe relays would need to have two poles.  You
need to make SURE that a relay has time to drop out, before
activating the other, or you'll short out your battery supply.
Waiting 1/10 of a second should be plenty.

Hmmm - do you propose to ensure the delay in the relay circuit or
programmatically?  If in the circuit, how?

This is (sort of) like connecting two back-to-back LED's
to an output, and lighting up one or the other with
Forward/Reverse.



Message has 1 Reply:
  Re: RCX motor voltage
 
The simple thing would be to do the short delay in the software. Identical relays usually 'make' faster than they 'break' due to energy stored in the magnetic circuit. It's hard to do this without active components. If you use a typical small (...) (25 years ago, 9-Nov-99, to lugnet.robotics.rcx)

Message is in Reply To:
  Re: RCX motor voltage
 
Wes, relays would work pretty well. (Still, how much current do your motors draw???) The LEGO motors draw about .35 Amps (350 Milliamperes) You could connect two 5V coil relays , each with a diode in series with the coil, connected oppositely to (...) (25 years ago, 9-Nov-99, to lugnet.robotics.rcx)

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