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 Robotics / RCX / 1464
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Subject: 
Re: GP2D12 IR sensor RCX active sensor interface?
Newsgroups: 
lugnet.robotics.rcx
Date: 
Wed, 10 Oct 2001 09:46:07 GMT
Viewed: 
2254 times
  
Hi all,

It seems I missed this thread...

Before I go ahead and build it, I though I'd ask is anyone is aware of any similar (simpler?) cicuits for hooking up one of these sensors to an RCX?
As suggested by Rainer, if you use an external battery everything is much
simpler, you could even use a 4.5V battery to avoid regulator.

Unfortanately his circuit board is a little bigger in physical dimensions than I hoped for and I'd like to get the response time up. Browsing around Lugnet there seems to have been several suggestions of diodes and voltage regulators with lower voltage drops, etc
I don't think you can improve this circuit with a simple optimisation of
components (but of course a better design can exist!). What you could do
would be to use SMT components to reduce size (I routinely solder chips with
0.5mm pitch...). And as I used plain vanilla capacitors, you could probably
get parts much smaller.
As for the response time, no hope here, or uses external supply...

And Philo's design switches it on and off every time you need data from the sharp.)

-* (Philo, do you have experiences how your cicuit affects the life time of the sharps ??) *-
IMHO there is no reason this on/off swithching could affect life of GP2D12.
Many designs use such switching to save power and/or multiplex several
sensors to avoid interference between them.

FYI - I just noticed in the component specs from Sharp that the GP2D12 (and GP2D15 for that matter) have a built-in voltage regulator. So is an external regulator a necessary precaution? Just curious...
Documentation calls for a 5V supply, with Absolute max = 7V (AFAIK the
internal regulator is used to provide detection circuitery with clean 3.3V
supply, the illumination Led is powered directly from 5V). So a regulator IS
required if you use higher than 5.5V voltage.

Philo



Message is in Reply To:
  Re: GP2D12 IR sensor RCX active sensor interface?
 
(...) Hi Gareth, maybe you don't need an external regulator ?!?! But, the specs also say that rating of supply voltage is "-0.3 to +7V". Do you know what happens to the sharp if supply voltage rises above +7V ??? (the mux has a supply voltage of +9V (...) (23 years ago, 9-Oct-01, to lugnet.robotics.rcx)

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