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Topic: hacking digital scale (Read 2744 times) previous topic - next topic

loewenbrau

Hi,

Having been inspired by casainho's bluetooth-enabled scale (http://code.google.com/p/casainho-projects/wiki/SdCardBathroomScale) I'd thought I would have a go at my own cheapo digital scale. However I've been having some problems identifying the components on the board. I'm guessing that the microprocessor is hidden underneath the black blob and that the 8 pin IC marked ISSI 546 406-26DL is an EEPROM. The real question is, what is the 14 pin IC marked AA|324 503BN (the logo is a swirly A)? Is it the op-amp? And in that case where can I find the datasheet for it? Can I assume that it is pin-compatible with an LM324?

Also I'm curious about the flat metal disc on the reverse side of the board, what is it exactly?

Thanks for your help!

Chagrin

The 14 pin chip does look like an amp. I'd suggest setting your multimeter to voltage and probe the pins while pressing down on the scale. Or post a less blurry picture for suggestions on which pin is likely the output.

The flat metal disk is a piezo disk. In this case it is being used as a speaker to produce a "beep". https://www.google.com/search?q=piezo&tbm=isch

Zapro

The 14-pin IC is a LM324, yes.

// Per.

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