I am doing a simple student project (weight watcher digital scale) that will recognise 10 users by a keypad through a password (#1234) to give each user the difference between the current weight and the past wight with the time difference.

any way, I need to bay a special bathroom scale that I can read its output (the weight) by a microcontroller. I dont know if this scale is provided or not? if yes, where? if not, guide me please.

 

Hello

That type of scale is quite common in the race car or go kart industry. Check the net - you will find many suppliers with scales. race car scales, go kart scales.

thanks [email protected]

 

You can buy balances that have RS-232 interfaces. But, these will cost more than your average bathroom scale that you can get at Wal-Mart. If you want to keep the cost down, get a digital one that you can take apart. Connect the microcontroller inputs in parallel with the 7-segment LEDs, and determine the actual weight by translating the 7-segment codes into integers.

 

The race cars scales are also quite expensive compared to a Wal-mart type scale, but if you still need a lead there, check out stockcarproducts.com .

I like the reading-the-7-segment outputs idea. Or how about an array of photo-diodes instead that can be added/removed non-invasively?

Cheers,
-Neil.

 

Pelouze (formally Sunbeam) offer scales with RS-232 output for under $100. They are available from the big ofice supply outlets (OfficeMax, etc.).

John Catch
http://www.inflowinc.com