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[cougar]

Cougar:

> Message:
> Background:
> I have a quick question about the project im just about finish with.
Im creating a voice activated remote control for Panasonic TVs and im
using an IO pin to output an infrared signal. I have a npn current
amplifier to boost the signal from 10 [mA] to 100[mA].
>
> Question:
> When I power the VR Stamp kit with my laptop with no power supplies
cord , the VR Stamp works fine but for some reason the IO pins are not
functioning. The IO pins still work but for some reason it cannot
control TV.
>
> Now when I just plug in the power supplies to my laptop, the IO pins
do work fine and is able to control my TV.
>
> Is there a ground issue involved that does not let the IO pins to
function correctly?
>
> I had seen this problem like 2 months ago but did not bother to mess
with it at the time, and now that Im trying to power my system with
batteries, it is not able to control a TV.



Bruno:
>Hi David,
>
>I seems that the I/O configuration of your MCU is not correctly set.
A good configuration should work on battery, any ground you may have or not.
>
>Can you please be more specific in a public message in forum, since it could interest other users too ?
>
>Thanks !
>
>Best regards,


Thank your for your fast reply:

Would the problem be related to my file config.mca or would it be the

cmpCtl |= 0x07;
p1CtlA = 255;
p1CtlB = 255;

I am using P1 port as my output.

Well once again thank you for your interest in helping me.

[BrunoG]

Hi David, thank you for posting here.

I assume you are using mikroE Easy VR Stamp dev. kit, correct ?

What do you mean by "The IO pins still work but for some reason it cannot control TV" ?

Did you check the USB power line voltage with and without power supply cord, maybe your laptop does not source enough current to feed both development board and your IR circuit ?

Is it possible to see your circuit schematic ? You can send it to me by email if you want.
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BrunoG, Administrator

[cougar]

Hi Bruno , thanks again for replying fast.

I am using the Easy VR Stamp kit.

What I mean about the I/O pins is that I still read a signal from the output pin and the VR stamp voice recognition still works fine. But now that I think of it I have not really checked the exact difference of the signals on the oscilloscope, I might start there.

Well my IR circuit is really simple : P1.1 is connected in series with a small resistor which is then connected to the base of the transistor(NPN), the emitter is grounded, and the collector is pulled up with 50 ohms of resistance connected in series with the IR led which then connects to 3.3 V as the source.

It drives about 100 mA., the output from P1 max is 10 mA, that cannot really drive anything.

The problem might be in the power supplies, but then again I cant use a power supplies. I need to use batteries. My infrared signal is a 50 bit signal modulating a 32 kHz signal.

well Im running out of ideas of what the problem is , hopefully I find it soon. anyhow thanks for all the help.

[cougar]

I just found out that my remote controller does work with batteries, as long as my battery ground is connected to earth ground.

Does this make sense?

[BrunoG]

How do you power your Easy VR Stamp board ? with external power supply socket ?
What is your battery voltage ?
Is the VR Stamp output correct anyway ?

The last time I needed to ground a circuit to earth was when I was young and doing some radio experiments
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BrunoG, Administrator

[cougar]

I am powering the Easy VR stamp kit with a laptop.

The output of my VR Stamp is not correct when it is not grounded.

Im able to power the VR Stamp only(not kit) with 3[V](2 AA). And when I ground the negative part of the battery, I get the output to work fine. Without the ground, I get a noisy signal.

So my output signal is not correct with a 3[V] from batteries. This is without the kit.

Well hope this makes sense. If not I will send you the schematic of the project.

[cougar]

Nevermind, problem has been fix, actually I made a simple mistake, and had different grounds on my remote.

Thanks for the help Bruno.

[BrunoG]

Hi David, glad to know it works. sometimes just talking about a problem helps to find a solution
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BrunoG, Administrator

[shamillion]

Okay, so I'm trying to find a way to define a pin as a two directional port. I have a temperature stamp that has a bidirectional data pin which sends and receives data. I was wondering if there is a way to set a particular pin in the stamp as such or if a particular pin has to be used. If anyone may have clue, could you shed some light. Thanks!

[BrunoG]

Hi shamillion,

Any VRSTAMP PORT pin may be used as an I/O pin, but depending on your hardware and your development board, you have to check if it is free or not.

I suggest you to have a look at the config.mca file of your project.

What is your temperature stamp data exchange protocol ?
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BrunoG, Administrator