LED Bar Graph Controls
Hi.. I have a project where two stamps will talk to each other - control in one direction and telemetry back.· I want to take voltage readings from the remote unit (possibly 2-3 batteries) and send that back to the control panel. I can get the voltage digitized to feed serially back to the control unit, but I want to use separate bar graph LEDs to show the status of the voltage. I will need to take the digital value and use it to drive the LED Bar graph. I need a source for info on where I can get some LEDs as well as how to drive them.
Thanks.
JG
Post Edited (tigershark35) : 9/8/2006 2:25:57 AM GMT
Thanks.
JG
Post Edited (tigershark35) : 9/8/2006 2:25:57 AM GMT
Comments
JG
This assumes that "value" and "result" are both words and "index" is a byte (or nibble). "value" and "result" can be the same
word if you don't need the input value for anything else. Pins 0 through 9 are connected to the anodes of the bar graph LEDS through appropriate current limiting resistors and the cathodes are connected to ground. This assumes that setting pins 0 through 9 high will turn on the LEDs. If not, you can change the values in the LOOKUP statement. Pin 0 is the lowest value LED. Pins 0 through 9 are set to OUTPUT during the program initialization.
Post Edited (Mike Green) : 9/8/2006 4:34:15 AM GMT
·· There is code in the Stamp Works 2 manual for driving·a DOT/BAR Graph directly from the BASIC Stamp (Experiment #5).· This manual is available as a free download from our website in PDF format.· I hope this helps.· Take care.
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Chris Savage
Parallax Tech Support
Jim
JAMECO now charges for shippig depending on where your parts are shiped from. If all comes from one place-one shipping charge. If from several distribution locations- you will receive individual shiping charges for each-check carefully before committing.
DIGIKEY has a larger selection and good on-line chat; whereas, JAMECO might be less expensive on some items. Best to do comarative shopping. Hope this helps.
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-Learn somthing about everything, and Everthing about somthing-
I thought of some other solutions like a plain shift register, but those don't usually have the ability to drive an LED at more than 6-10ma. If that's enough for you, that would be a cheaper, simpler solution (like the 74HC595).
Yes, a lot of what Jameco now "stocks" is actually shipped direct from the manufacturer. A small order could easily have multiple shipping charges that exceed the actual value of the items ordered. Shipping charges for online purchases can be a killer.
I would like to add Mouser as a recommended place to buy parts. You only pay actual shipping costs, and there is no handling charge and no minimum order. They are very hobbyist friendly in this regard. They ship same day almost every time and there is no additional shipping charge if an item is back-ordered and ships at a later date. Also, if you make a purchase from them, you will start to receive their free 2 inch thick catalog in the mail, every 90 days [noparse]:)[/noparse]
- Rick
One point I failed to mention in my original note is we should always check the Parallax web site. They often times have competative pricing on items and we should support them first if possible. They provide us with so much free support, we should support them whenever possible.
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Chris Savage
Parallax Tech Support
JG
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Chris Savage
Parallax Tech Support
Do you have some sample circuits using the 74HC595 or the expander that you mentioned earlier in this thread?
Thanks
·· The Binary Digital Clock can be found at the first link...A PDF copy of the Stamp Works 2 manual can be found at the bottom of the second link.· Take care.
http://forums.parallax.com/showthread.php?p=552892
http://www.parallax.com/detail.asp?product_id=27220
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Chris Savage
Parallax Tech Support