LCD + Sharp GP2D120 = haywire

Started by arnajon October 5, 2005
Hi,

I'm trying to use a standard LCD (16x2) to display a reading from a
sharp gp2d120 distance sensor but having poor luck. The LCD works
great but when I plug the sensor to the circuit the screen either
hangs up or displays nothing or nonsens. I also noticed that
programming the pic (via ICSP) fails while the sensor is connected.
I'm aware that the gp2d120 is both power hungry but I'm pretty sure
that my power supply can handle the load. I've also read that the
sensor is a noisy device but adding the recommended caps across v+ and
gnd does no good.

Thanks in advance,
Arnar B.
Iceland


--- In piclist@picl..., "arnajon" <abj@f...> wrote:
> Hi,
>
> I'm trying to use a standard LCD (16x2) to display a reading from a
> sharp gp2d120 distance sensor but having poor luck. The LCD works
> great but when I plug the sensor to the circuit the screen either
> hangs up or displays nothing or nonsens. I also noticed that
> programming the pic (via ICSP) fails while the sensor is connected.
> I'm aware that the gp2d120 is both power hungry but I'm pretty sure
> that my power supply can handle the load. I've also read that the
> sensor is a noisy device but adding the recommended caps across v+
and
> gnd does no good.

At a minimum you need 33 ufd across Vcc and Gnd where the sensor
connects to the PCB (or whatever). These devices are used on robots
all the time and they are known to work quite well. But only if there
is a large capacitance where the device receives power.

>
> Thanks in advance,
> Arnar B.
> Iceland