Subject:
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Re: Voltage Sensor
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Newsgroups:
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lugnet.robotics
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Date:
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Mon, 16 Sep 2002 17:03:35 GMT
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Viewed:
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724 times
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Are you powering the RCX from this battery?
If so you can use the RCX it'self to monitor the battery.
task main()
{
while (true)
{
SetUserDisplay(BatteryLevel(), 3);
}
}
I use this to detect if my 1.0 RCX is plugged in or on batterys.
Hope that helps.
Dean
"Tom Beattie" <tom@magneticpie.com> wrote in message
news:H2J17p.Ior@lugnet.com...
> Hello fellow Mindstomers,
>
> I am seeking some direction in the development of a Voltage Sensor I wish • to
> use with my RCX.
>
> I have solar cell connected to a 12Volt (1.3A) sealed lead acid battery • via
> a small trickle charger PCB (bought as a kit). The solar cell charges the
> battery when sun permits. Connected to the battery I have a voltage
> regulator (again, bought as a kit) to bring the output of the battery to 9
> Volts, which I then feed to various lego components. i.e motors, lights,
> RCX, etc. This works well.
>
> What I want to do is to be able to monitor the batteries voltage via a RCX
> sensor input
> I have made the following assumptions
> 1 Sensor type should be a "Light sensor" - In order to monitor a 0V - • 5V
> sensor input reading
> 2 Use a General Purpose Analog Interface as per Michael Gasperi's fab • web
> site http://www.plazaearth.com/usr/gasperi/gpa.htm
> 3 Use some sort of 'resistive divider' setup to bring the monitored
> battery output voltage within the 0V - 5V input range of the sensor.
> http://news.lugnet.com/robotics/?n=18648
> 4 Convert the sensor reading within a RCX program to bring it back to • the
> 0V - 12V range
>
>
> My questions are:
> 1 Is this the 'right' way to go about this sort of thing?
> 2 What is the arrangement of the resisters in a 'resistive divider' • setup
> relative to the battery and the analog interface.
> 3 How might these affect the reading generated in the analog interface
> given that it also has a resistor (R1 @ 2.2K)?
> 4 By reducing voltage am I going to overload the sensor input on my RCX
> (i.e fry it with too much current)
> 5 Am I reinventing the wheel here, and a simpler way already exists to
> measure voltage through a RCX on external battery sources.
>
> Thanks for your time
>
> Tom Beattie
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Message has 3 Replies:
 | | Re: Voltage Sensor
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| Hello, (...) This idea, while in itself interesting, will not work when the 12V battery gets regulated down to 9V. This is because these 9V will barely vary across the regulator's permitted input range. If of course the regulator is specifically (...) (22 years ago, 16-Sep-02, to lugnet.robotics)
| | | Re: Voltage Sensor
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| (...) Thanks Dean, I had some thought in monitoring the battery level directly through RCX. But potentially I wanted to monitor multiple battery sources so I thought I might as well as develop an external sensor. Another thought was that the same (...) (22 years ago, 17-Sep-02, to lugnet.robotics)
| | | Re: Voltage Sensor
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| Tom, it is possible to also buy ready made voltage sensors for the RCX, see (URL) have used a most of the sensors from this company for data-logging purposes, but have not yet used the voltage sensor. If you would like more info, I can probably try (...) (22 years ago, 18-Sep-02, to lugnet.robotics)
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Message is in Reply To:
| | Voltage Sensor
|
| Hello fellow Mindstomers, I am seeking some direction in the development of a Voltage Sensor I wish to use with my RCX. I have solar cell connected to a 12Volt (1.3A) sealed lead acid battery via a small trickle charger PCB (bought as a kit). The (...) (22 years ago, 16-Sep-02, to lugnet.robotics)
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