digital weighting scale schematics

LCD or LED?

Buffer/Driver?

ASIC

Is your pressure sensor a load cell? see

How many wires do you need to connect to that pressure sensor?

Regards

I made a mistake it's a quad operational amplifier not a hex inverter. I also think it's not a pressure sensor. It's a small 1/4"x1/4" box with a small button on it with a metal lever shrink tubed to the button. The more weight on the lever the more pressure is applied to the button.

Which means that the pressure transducer would be "under the button".

Pre-amp and SigmaDelta A2D. We are doing the same. Commonly done for chip without internal A2D.

Why not? Weight is pressure.

Or a MEMS pressure sensor.

_cell

Three.

From Wikipedia, the free encyclopedia: A transducer is a device, usually electrical, electronic, electro- mechanical, electromagnetic, photonic, or photovoltaic that converts one type of energy or physical attribute to another for various purposes including measurement or information transfer (for example, pressure sensors).

A Micro Electronics Mechanical System (MEMS) pressure sensor qualify as such.

I repeat the question: Is it using LCD? Since "Charder" is in Taiwan and our ASIC supplier is also in Taiwan, perhaps they are related? We are using one of the most popular LCD uC/ASIC from Taiwan.

see

I seems to be just talking to myself, as always. Anyway,

1. Reading from a pressure sensor with an external op amp.
2. Sampling 10 bits A2D by 6 bits PWM and 4 bits software loop.
3. Driving a 3 digits LCD.

// Pressure sensor (Freescale MPX4080D) // 1. Vout 2. Gnd 3. +5

// Op amp (National LM358) // +-----------------------------+ // \\ |\\ | // -|-\\_-- PD0 PS0-- 470K --+-- 0.1uF -+ // Vin-|+/ | // |/ GND

Adjust R and C value for desired readout Connect Vout of MPX4080D to Vin of LM358 PS0 is the PWM output pin 0 PDO is the port D input pin 0 see:

See also:

=A0 =A0 =A0|

=A0 =A0 =A0 =A0GND

Please let me ask a question, I am just curiouos. Is 6502 still in use as a processor for such applications these days? A few years ago I had studied on weighing scales. One such design solution as suppported by Analog devices is using a System on Chip ADuC847:

regards

=A0 =A0 =A0 =A0|

=A0 =A0 =A0 =A0 =A0GND

Yes, it is a very popular processor for low end embedded apps when cost is the major factor.

You have to be careful using them, though. You don't want them to all turn sentient and take over mankind...

Tim

turn

But you can reprogram them to protect mankind, as in T2.

use

l turn

:)

They are sentient, and they love to laugh their little silicon asses off at bad programmers. ;-)

Absolutely. It IS a "pressure transducer". A micro-phone is an "Audio Pressure Transducer".

So is a speaker.