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Hello,
for work i've been building a lego crane, which is used to
attract people to my company's stand at fairs/conferences. One
of the problem is the batteries. It's annoying that every once in
a while someone has to change them. I've heard that version
1.0 of the rcx had a power jack, and that version 2.0 'kinda' also has
one, only it's disabled or obscured (or something).
I've been googling my way through the internet, trying to find some
sort of rcx-modding-guide, but to no avail.
Is there anyone here that has some info on how i can get my rcx version
2.0 to work with an external power supply?
Any help would be appreciated.
Kind regards,
Ilja
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I. Smoltsak wrote:
> Hello,
>
> for work i've been building a lego crane, which is used to
> attract people to my company's stand at fairs/conferences. One
> of the problem is the batteries. It's annoying that every once in
> a while someone has to change them. I've heard that version
> 1.0 of the rcx had a power jack, and that version 2.0 'kinda' also has
> one, only it's disabled or obscured (or something).
>
> I've been googling my way through the internet, trying to find some
> sort of rcx-modding-guide, but to no avail.
>
> Is there anyone here that has some info on how i can get my rcx version
> 2.0 to work with an external power supply?
>
> Any help would be appreciated.
>
> Kind regards,
> Ilja
http://nanobapt.homelinux.com/mindstorms/old/tips_tricks/tips_autres.htm
it's in french but google can understand it ;-)
nanobapt
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Hello Ilja,
>
> Is there anyone here that has some info on how i can get my rcx version
> 2.0 to work with an external power supply?
Here is the method that I used in my motors tests
(http://www.philohome.com/motors/motorcomp.htm), that require no modification to
RCX: use two fake batteries assembled from the sawed ends of old alkaline
batteries, maintained at the right spacing with rods of hot melting glue.
See http://www.philohome.com/motors/fake-batt1.jpg and
http://www.philohome.com/motors/fake-batt.jpg.
These fake batteries are connected to a regulated 9V power supply (red wire
connected to +)
And of course...
Caution: I shall not be held responsible if you burn your RCX with incorrect
voltage or bad polarity
Caution2: batteries contain hazardous chemicals that can be dangerous for your
health. Open them at your own risk and only if you know what you are doing!!!
Philo
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I've done something similar but used wooden dowels cut to size. No harsh
chemicals to mess with. :)
Jim West
www.jameswest.com
The box said Windows 95 or better, so I installed Linux.
---------- Original Message -----------
From: "Philippe Hurbain" <philohome@free.fr>
To: lego-robotics@crynwr.com
Sent: Tue, 25 Nov 2003 19:49:18 GMT
Subject: Re: External power supply ?
> Hello Ilja,
> >
> > Is there anyone here that has some info on how i can get my rcx version
> > 2.0 to work with an external power supply?
>
> Here is the method that I used in my motors tests
>
> (http://www.philohome.com/motors/motorcomp.htm), that require no
> modification to RCX: use two fake batteries assembled from the sawed
> ends of old alkaline batteries, maintained at the right spacing with
> rods of hot melting glue.
>
> See http://www.philohome.com/motors/fake-batt1.jpg and
> http://www.philohome.com/motors/fake-batt.jpg.
>
> These fake batteries are connected to a regulated 9V power supply
> (red wire connected to +)
>
> And of course...
> Caution: I shall not be held responsible if you burn your RCX with incorrect
> voltage or bad polarity
> Caution2: batteries contain hazardous chemicals that can be
> dangerous for your health. Open them at your own risk and only if
> you know what you are doing!!!
>
> Philo
------- End of Original Message -------
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In lugnet.robotics, Philippe Hurbain wrote:
> Hello Ilja,
> >
> > Is there anyone here that has some info on how i can get my rcx version
> > 2.0 to work with an external power supply?
>
> Here is the method that I used in my motors tests
> (http://www.philohome.com/motors/motorcomp.htm), that require no modification to
> RCX: use two fake batteries assembled from the sawed ends of old alkaline
> batteries, maintained at the right spacing with rods of hot melting glue.
>
> See http://www.philohome.com/motors/fake-batt1.jpg and
> http://www.philohome.com/motors/fake-batt.jpg.
>
> These fake batteries are connected to a regulated 9V power supply (red wire
> connected to +)
>
> And of course...
> Caution: I shall not be held responsible if you burn your RCX with incorrect
> voltage or bad polarity
> Caution2: batteries contain hazardous chemicals that can be dangerous for your
> health. Open them at your own risk and only if you know what you are doing!!!
>
> Philo
Philo,
I want to attempt the conversion to an external power source. I have looked at
your page but I have a few questions. Please forgive me that I know next to
nothing about electric power and electronics -- or so it seems.
- Your regulated power supply was able to put out 9v.. at what m/A is
recommended for the RCX 2.0?
- I see "regulated" wall-warts listed at radio shack. Would one of these
suffice?
- In another lugnet posting on this topic, a fellow used a voltage regulator
7809 or 7805. Is this necessary only if using an unregulated dc supply?
- I would still have the issue of having to program once powered by the adapter.
Is there some way to have batteries in it and have it switch. I want to run
some atuomation at a train show and don' have a working laptop.
Thanks
ken
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Hi Ken,
>
> - Your regulated power supply was able to put out 9v.. at what m/A is
> recommended for the RCX 2.0?
Maximum RCX power consumption is 1500 mA (there is a fuse inside rated 1.5A).
Anything rated at least 1A should be OK.
>
> - I see "regulated" wall-warts listed at radio shack. Would one of these
> suffice?
They should, if they are really regulated (some cheap warts advertised as
regulated are not so good...). A LEGO 9V train adaptor could be used too.
>
> - In another lugnet posting on this topic, a fellow used a voltage regulator
> 7809 or 7805. Is this necessary only if using an unregulated dc supply?
If your wart has good regulation, they are not needed.
CAUTION - Don't forget to take care of polarity too !!!
>
> - I would still have the issue of having to program once powered by the adapter.
> Is there some way to have batteries in it and have it switch. I want to run
> some atuomation at a train show and don' have a working laptop.
That's the problem - automatic switching is not so easy to do if you don't want
to do some electronics. Perhaps the simplest solution would be to use a RCX
first version with power input :-/
Cheers,
Philo
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In lugnet.robotics, Philippe Hurbain wrote:
> > - I see "regulated" wall-warts listed at radio shack. Would one of these
> > suffice?
>
> They should, if they are really regulated (some cheap warts advertised as
> regulated are not so good...). A LEGO 9V train adaptor could be used too.
CAUTION!!! The wall-wart that comes with the train adaptor puts out an AC
voltage that will likely damage your RCX if used this way!!! I have read
reports of people burning out their RCXes by connecting the wall-wart to the
battery contacts inside the RCX 2.0, as the RCX without the power jack does not
have any power rectification circuitry inside.
You *might* be able to use the output from the train speed controller, which is
DC, but this could easily backfire if you accidentally hook it up with reverse
polarity or turn the speed control knob in the wrong direction.
> > - I would still have the issue of having to program once powered by the adapter.
> > Is there some way to have batteries in it and have it switch. I want to run
> > some atuomation at a train show and don' have a working laptop.
>
> That's the problem - automatic switching is not so easy to do if you don't want
> to do some electronics. Perhaps the simplest solution would be to use a RCX
> first version with power input :-/
You could use both batteries and a DC adaptor, but not at the same time. You
need to have power leads that allow you to connect your adaptor to the end
battery terminals inside the RCX. Just be sure to remove at least one of the
batteries from the RCX as soon as you connect the external power supply or else
you could start a fire. You can remove a battery just before you connect the
external power supply-- as long as the power is not disconnected for more than a
few seconds, the RCX should retain its memory.
If you are not very comfortable with electronics, your best bet is to track down
a 1.0 RCX with the external power jack, as Philippe suggests.
- Chris.
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>
> CAUTION!!! The wall-wart that comes with the train adaptor puts out an AC
> voltage that will likely damage your RCX if used this way!!! I have read
> reports of people burning out their RCXes by connecting the wall-wart to the
> battery contacts inside the RCX 2.0, as the RCX without the power jack does not
> have any power rectification circuitry inside.
>
> You *might* be able to use the output from the train speed controller, which is
> DC, but this could easily backfire if you accidentally hook it up with reverse
> polarity or turn the speed control knob in the wrong direction.
You are right Chris, the train controller is not a good idea. Indeed all Lego
adaptors (including the one for RCX 1.0) provide AC only. And turning the knob
in the wrong direction is just too easy.
Thanks for correcting my misleading explanations!
Philo
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In lugnet.robotics, Philippe Hurbain wrote:
> Hi Ken,
>
> >
> > - Your regulated power supply was able to put out 9v.. at what m/A is
> > recommended for the RCX 2.0?
>
> Maximum RCX power consumption is 1500 mA (there is a fuse inside rated 1.5A).
> Anything rated at least 1A should be OK.
I ran by Radio Shak today and they had one 3-12v rated at 1A I think. It was
$37!
> >
> > - I see "regulated" wall-warts listed at radio shack. Would one of these
> > suffice?
>
> They should, if they are really regulated (some cheap warts advertised as
> regulated are not so good...). A LEGO 9V train adaptor could be used too.
> >
> > - In another lugnet posting on this topic, a fellow used a voltage regulator
> > 7809 or 7805. Is this necessary only if using an unregulated dc supply?
>
> If your wart has good regulation, they are not needed.
>
> CAUTION - Don't forget to take care of polarity too !!!
>
> >
> > - I would still have the issue of having to program once powered by the adapter.
> > Is there some way to have batteries in it and have it switch. I want to run
> > some atuomation at a train show and don' have a working laptop.
>
> That's the problem - automatic switching is not so easy to do if you don't want
> to do some electronics. Perhaps the simplest solution would be to use a RCX
> first version with power input :-/
I have considered that too. But uncovered another potential complication. In
researching around somewhere... I think at lego.com actually it said that RCX
1.0 does not support variables?! Is that possible? My program is not
complicated but does use a variable. I might be able to restructure, but it
hurts my head.
Another consideration: Please forgive me for not knowing squat about
electronics... or is that "I *know* squat?"
I was reading up on LEDs and so forth and saw something using a transistor.
Wouldn't it be feasible to run power say from a train controller through a
transistor, and use the RCX to turn that flow on/off? The train controller
provides the juice for motors, lights whatver (or rather it's wall awart does)
and the RCX just intervenes. Seems like that would draw a lot less power from
the RCX. I figured this was possible and maybe not hard but did not know what
the component was called that would be used.
Also, maybe someone can chime in, but as to holding the program, I seem to
recall seeing one of the solutions that involved external power invloved
connecting a power jack. The guy said he could just quickly swap the wall wart
and a 9-volt bat(with a plug attached)... he cautioned to have the rcx power off
at the time and said that it woudl allow him to transport. Not sure who that
was and can't find the post or web page again!
Where's the RCX 3.0 when you need it? You know the one with the battery backup
and AC jack, about half the size with 6 outputs and 12 inputs and ... sorry, I
am a bit delerious right now.
> Cheers,
> Philo
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> > Maximum RCX power consumption is 1500 mA (there is a fuse inside rated 1.5A).
> > Anything rated at least 1A should be OK.
>
> I ran by Radio Shak today and they had one 3-12v rated at 1A I think. It was
> $37!
I think you could find something cheaper than that (with a fixed-voltage
output?)
>
> I have considered that too. But uncovered another potential complication. In
> researching around somewhere... I think at lego.com actually it said that RCX
> 1.0 does not support variables?! Is that possible? My program is not
> complicated but does use a variable. I might be able to restructure, but it
> hurts my head.
The RIS 1.0 didn't support variables, but 1.0 bricks can use latest firmware so
there is NO problem here !
>
> Another consideration: Please forgive me for not knowing squat about
> electronics... or is that "I *know* squat?"
> I was reading up on LEDs and so forth and saw something using a transistor.
> Wouldn't it be feasible to run power say from a train controller through a
> transistor, and use the RCX to turn that flow on/off? The train controller
> provides the juice for motors, lights whatver (or rather it's wall awart does)
> and the RCX just intervenes. Seems like that would draw a lot less power from
> the RCX. I figured this was possible and maybe not hard but did not know what
> the component was called that would be used.
As Chris mentionned elswhere in this thread, a train controller is NOT a good
idea to power a RCX since it's just too easy to reverse polarity!
>
> Also, maybe someone can chime in, but as to holding the program, I seem to
> recall seeing one of the solutions that involved external power invloved
> connecting a power jack. The guy said he could just quickly swap the wall wart
> and a 9-volt bat(with a plug attached)... he cautioned to have the rcx power off
> at the time and said that it woudl allow him to transport. Not sure who that
> was and can't find the post or web page again!
Yes, that's a simple method to solve the backup problem. There is a capacitor
inside the RCX that provide enough current to keep memory alive during battery
changes. You have a few seconds to do the swap. Just make sure that the RCX is
powered off or the increased current drain would mean instantaneous erasing!
>
> Where's the RCX 3.0 when you need it? You know the one with the battery backup
> and AC jack, about half the size with 6 outputs and 12 inputs and ... sorry, I
> am a bit delerious right now.
Ah? I thought it derived its power from the built in solar panel ;o)
Philo
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In lugnet.robotics, Philippe Hurbain wrote:
> > > Maximum RCX power consumption is 1500 mA (there is a fuse inside rated 1.5A).
> > > Anything rated at least 1A should be OK.
> >
> > I ran by Radio Shak today and they had one 3-12v rated at 1A I think. It was
> > $37!
>
> I think you could find something cheaper than that (with a fixed-voltage
> output?)
> >
> > I have considered that too. But uncovered another potential complication. In
> > researching around somewhere... I think at lego.com actually it said that RCX
> > 1.0 does not support variables?! Is that possible? My program is not
> > complicated but does use a variable. I might be able to restructure, but it
> > hurts my head.
>
> The RIS 1.0 didn't support variables, but 1.0 bricks can use latest firmware so
> there is NO problem here !
>
> >
> > Another consideration: Please forgive me for not knowing squat about
> > electronics... or is that "I *know* squat?"
> > I was reading up on LEDs and so forth and saw something using a transistor.
> > Wouldn't it be feasible to run power say from a train controller through a
> > transistor, and use the RCX to turn that flow on/off? The train controller
> > provides the juice for motors, lights whatver (or rather it's wall awart does)
> > and the RCX just intervenes. Seems like that would draw a lot less power from
> > the RCX. I figured this was possible and maybe not hard but did not know what
> > the component was called that would be used.
>
> As Chris mentionned elswhere in this thread, a train controller is NOT a good
> idea to power a RCX since it's just too easy to reverse polarity!
Right. But that's not what I was asking or suggesting. The idea was...elave
the RCX2.0 as is on batteries. Run some other devices off of whatever power
source, but control that power source via program logic from the RCX. The RCX
could run relays or whatever the devices would be called. It seems like this
should be simple..? But I know next to nothing of electronics.
In surfing the web... seems like a transistor. It has three 'legs' right?
power flows in one side and out the other and is controlled by power put in on
the middle leg?
Wouldn't this be easy to construct?
Ken
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In lugnet.robotics, Ken Koleda wrote:
> Right. But that's not what I was asking or suggesting. The idea was...elave
> the RCX2.0 as is on batteries. Run some other devices off of whatever power
> source, but control that power source via program logic from the RCX. The
> RCX could run relays or whatever the devices would be called. It seems like
> this should be simple..? But I know next to nothing of electronics.
It sounds like what you're wanting to do is to effectively turn a
battery-powered RCX into the rough equivalent of a multi-function
smart-solenoid. All final output devices (lights, motors, etc.) are powered by
switched 9v AC supplies, and the battery-powered RCX just controls the switches.
> In surfing the web... seems like a transistor. It has three 'legs' right?
> power flows in one side and out the other and is controlled by power put in > on the middle leg?
Yeah, that's a transistor, but from what I can tell you'd need to be able to
switch between negative and positive charges on the third leg to affect the flow
between the other two. Can the RCX do that?
> Wouldn't this be easy to construct?
Without ripping apart other electronic bricks to cannibalize, you're pretty much
stuck working with store-bought transistors. Then it's a question of whether
the RCX can send a negative current down one wire, and whether a transistor has
a default "at-rest" state, or if it always stays permanently switched until it
receives the opposite charge.
I'm not an electronics expert either, and I have no RCX experience at all, but I
do know someone who is an electronics expert. It won't help you out for GATS
this weekend, but I might be able to do some go-between work to figure out what
you'd need to do to make this work for future shows.
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"ken koleda" <kkoleda@co.wayne.mi.us> wrote in message
news:HrD4zL.1sEF@lugnet.com...
<<snip>>
> Philo,
>
> I want to attempt the conversion to an external power source. I have • looked at
> your page but I have a few questions. Please forgive me that I know next • to
> nothing about electric power and electronics -- or so it seems.
>
> - Your regulated power supply was able to put out 9v.. at what m/A is
> recommended for the RCX 2.0?
>
> - I see "regulated" wall-warts listed at radio shack. Would one of these
> suffice?
>
> - In another lugnet posting on this topic, a fellow used a voltage • regulator
> 7809 or 7805. Is this necessary only if using an unregulated dc supply?
>
> - I would still have the issue of having to program once powered by the • adapter.
> Is there some way to have batteries in it and have it switch. I want to • run
> some atuomation at a train show and don' have a working laptop.
>
> Thanks
>
> ken
Hi Ken,
I have been using a Radio Shack Cat #273-1772 with good results. It is a
regulated supply that is rated for 9 VDC 1300 mA. When I read the no-load
output with my DVM it shows 9.4 volts -- close enough for me. I suppose you
could smoke a motor using it if you really loaded the motor up, but I
haven't had any problems. The only issue is that you lose the programming
when you unplug it (though I never considered the earlier reply from Philo
about a capacitor. I will have to see if I can get it unplugged and put
batteries in without losing the programs).
I made dummy batteries as Philo suggested on his website (though mine are
square). I bought a size H female connector also at Radio Shack, which I
epoxied into a hole I drilled intothe side of the rear 'battery'. This
lines up with the notch in the battery case of the RCX. I then cut a
matching notch in the battery cover so I can have the cover on and still
plug in the power supply.
Jim
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lego-robotics@crynwr.com (I. Smoltsak) writes:
>
> I've heard that version 1.0 of the rcx had a power jack,
> and that version 2.0 'kinda' also has one, only it's
> disabled or obscured (or something).
There was a rumour that 2.0 would have a power jack,
which proved to be false when it came out.
Personally I also sometimes use a stabilized 9V 1.5A supply,
but as the others said, be careful with that.
Jürgen
--
Jürgen Stuber <stuber@loria.fr>
http://www.loria.fr/~stuber/
> rot 13 "fr"
"se"
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