Tech4all group blog

Re: [tech4all] 8085 -indicator

On 6/11/05, b_prasana <b.prasana@sify.com> wrote:
> Dear Friends
>
> I am a E.C.E. student entering in to third year. I want
> to do a project ,i.e.,
>
> A water level indicator using 8085 microprocessor and
> 8255 interface.
> Can anyone help me in this regard, like how to get
> about it?
> With regards
> B.Prasana
>

I suspect - as this is a sensor based question, that posting on both
the OrionRobots forums (http://orionrobots.co.uk/forums.php) and the
DPRG list would get a response from people who have done this before.

Just out of interest- why choose the 8085? Or was that determined by
the course? I would have chosen a PIC for this you see.

What do you intend for the water level sensor?

You could use a discrete set of conductors - which would then be
conducting when they are each below the water level. In which case -
although it is digital, you may want to clean up the signal between
the water and the 8255 with a single transistor.

You could also use a float, with a rotation sensor - like a variable
resistor. You would then use an A to D between this and the 8255, or a
biased transistor to switch when it reaches a certain level.

One well documented property of water is that the interface between it
and air causes light to refract - so by calculating (or measuring) the
angles, you could set up an IR based system that will detect when the
light is reflected at a certain angle form the bottom of the tank, the
angle is determined by the refraction - which is determined by the
water depth. This could be done with a single IR Led, and a
Phototransistor - keeping the electronics simple. You would then use
guides to ensure the angles the light is being emitted and received.
You will need to ensure the bottom of the water container is
reflective.

If you use the electronics to set a threshold, then you could use the
8255 in mode 1 or 2 and use control signals to interrupt the CPU, and
respond to that.

However- if you want the A to D continuous based monitoring - then you
are better off writting a program to regularly poll the port and test
the values on that.

Good luck,
Orion
--
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posted by Bharath @ 12:44 PM