Heartbeat

MacGeek117 · 2005-09-18 21:53

I'm developing this project for my brother. This is the parts list:
attachment.php?attachmentid=73716

I'd like to have feedback and any advice you can give·on this project. Here is the schematic:

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There are 10 kinds of people in the world,

those that know binary and those that don't.
www.goldmine-elec.com
www.parallax.com
www.expresspcb.com
www.startrek.com

steve_b · 2005-09-18 23:07

Do you just want the string of LEDs to light all at once? or is there supposed to be a knight rider effect?

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·

Steve

"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."

Jon Williams · 2005-09-18 23:14

Perhaps this is better posted in the SX forum as it is clearly still a "work in progress"

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Jon Williams
Applications Engineer, Parallax

Chris Savage · 2005-09-18 23:43

Jon is correct...And presto, it's in the appropriate forum.

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Chris Savage
Parallax Tech Support
csavage@parallax.com

MacGeek117 · 2005-09-21 02:24

Thanks, Jon! Thanks, Chris! Steve, not really. It is supposed to look like a beating heart.

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There are 10 kinds of people in the world,

those that know binary and those that don't.
www.goldmine-elec.com
www.parallax.com
www.expresspcb.com
www.startrek.com

nick bernard · 2005-09-21 17:32

supply the led's w/ V+ instead of +5 to take some of the load off of the regulator. if you simply want flashing use a 555 timer to drive your fet. you may not need a regulator in that case.

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engineer, fireman, bowler, father, WoW addict [noparse];)[/noparse]

MacGeek117 · 2005-09-21 20:38

I thought the same thing, Nick. But my brother wants it to look like a heart, bump, short pause, bump long pause and repeat.
bugg

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There are 10 kinds of people in the world,

those that know binary and those that don't.
www.goldmine-elec.com
www.parallax.com
www.expresspcb.com
www.startrek.com

nick bernard · 2005-09-22 13:03

ok

also i use usually use fets to switch ground. Like so

V+ <---/\/\/\/

|>|

DGS

>Ground

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engineer, fireman, bowler, father, WoW addict [noparse];)[/noparse]

Post Edited (nick bernard) : 9/22/2005 1:02:35 PM GMT

MacGeek117 · 2005-09-25 17:24

Oversight. I will do like you said.
bugg

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There are 10 kinds of people in the world,

those that know binary and those that don't.
www.goldmine-elec.com
www.parallax.com
www.expresspcb.com
www.startrek.com

MacGeek117 · 2006-01-06 18:31

This is turning out to be quite a project! I have attached the new info. The LEDs are supposed to shine on the cylinder heads.

RoboGeek

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There are·3 kinds of people in the world,

the dreamers, the do-ers, and the "Oh, what's this button do"-ers.
Formerly bugg.
www.parallax.com
www.goldmine-elec.com
www.expresspcb.com
www.startrek.com

Beau Schwabe · 2006-01-06 18:49

One thing that I notice from the schematic, is that ALL of the LED's are in parallel. This is usually a no-no and should
be avoided. With a +5V supply you can place 2LED's in series with a current limiting resistor, or you might be able to
get away with 3LED's in series if the Vled is less than 1.6V with a small current limiting resistor. If you choose to use
the +Vsupply instead of +5V, then you might be able to get away with more LED's in series.

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Beau Schwabe

IC Layout Engineer
Parallax, Inc.

MacGeek117 · 2006-01-06 19:10

OK, I didn't know that. The LEDs will be running of a motorcycle battery.
RoboGeek

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There are·3 kinds of people in the world,

the dreamers, the do-ers, and the "Oh, what's this button do"-ers.
Formerly bugg.
www.parallax.com
www.goldmine-elec.com
www.expresspcb.com
www.startrek.com
·

Bean · 2006-01-06 19:43

Bugg,
Even better if you are using the FET to ground the LEDs.
You can put 6 LEDs in series with a resistor and connect the + to the battery (+12 to +14) and use the FET to ground the "-" end.
Make two strings (controlled by the same FET) and you have your 12 LEDs with no strain on the regulator.
Also 50Mhz is kinda overkill 4MHz would work fine and draw less current. Although your probably not worried being powered by a motorcycle battery.
Bean.

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"SX-Video·Module" Now available from Parallax for only $28.95

http://www.parallax.com/detail.asp?product_id=30012

"SX-Video OSD module" Now available from Parallax for only·$49.95
http://www.parallax.com/detail.asp?product_id=30015

Product web site: www.sxvm.com

"If I was king for just one day...I don't think I could screw things up any worse [noparse];)[/noparse]"
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MacGeek117 · 2006-01-06 20:16

>>Also 50Mhz is kinda overkill<< The 50MHz resonators are the cheapest.
>>Even better if you are using the FET to ground the LEDs.<< Oversight when making the schematic.

I will be using more that 12 LEDs, more like ~15-20.
RoboGeek

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There are·3 kinds of people in the world,

the dreamers, the do-ers, and the "Oh, what's this button do"-ers.
Formerly bugg.
www.parallax.com
www.goldmine-elec.com
www.expresspcb.com
www.startrek.com
·

Forrest · 2006-01-07 00:09

FYI the Parallax Robolympic medal has a SX28 clocked at 4 MHz controlling 105 LED's
www.parallax.com/detail.asp?product_id=28099

MacGeek117 · 2006-01-07 22:36

Does anyone know the pinout for Parallax part #153-00002 (MOSFET)?
RoboGeek

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There are·3 kinds of people in the world,

the dreamers, the do-ers, and the "Oh, what's this button do"-ers.
Formerly bugg.
www.parallax.com
www.goldmine-elec.com
www.expresspcb.com
www.startrek.com
·

ChrisP · 2006-01-08 01:11

Typicaly fet are pinned left to right.... Gate Drain Source or Switch voltage, Load, Ground on an N channel fet.

MacGeek117 · 2006-01-11 00:28

Thanks, Chris. I need to have the rate of flashing change, but I'm not sure of how to do that, could I please have some help?
P.S. I will have two active-high pushbuttons connected to RB.1 and RB.2.
RoboGeek

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There are·3 kinds of people in the world,

the dreamers, the do-ers, and the "Oh, what's this button do"-ers.
Formerly bugg.
www.parallax.com
www.goldmine-elec.com
www.expresspcb.com
www.startrek.com

ChrisP · 2006-01-11 01:30

Are you looking for it to change automaticaly, just ramp up and down, change with something external or just be able to adjust the flash rate?

MacGeek117 · 2006-01-11 03:17

I'd like to have two pushbuttons, one to increase and one to decrease the rate.
RoboGeek

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There are·3 kinds of people in the world,

the dreamers, the do-ers, and the "Oh, what's this button do"-ers.
Formerly bugg.
www.parallax.com
www.goldmine-elec.com
www.expresspcb.com
www.startrek.com
·

ChrisP · 2006-01-11 05:14

One to increase and one to decrease shouldnt be bad since it wont be ramping at a set rate on its own. How many LED's total in how many sets? I'll see what I can come up with, this is something that I should be able to get a grip on.

MacGeek117 · 2006-01-11 21:07

Thank you very much! I have tried a couple ways but could not get them to work. I don't remember what I did.
RoboGeek

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There are·3 kinds of people in the world,

the dreamers, the do-ers, and the "Oh, what's this button do"-ers.
Formerly bugg.
www.parallax.com
www.goldmine-elec.com
www.expresspcb.com
www.startrek.com
·

pjv · 2006-01-12 04:25

Hi Geek;

To help you gain experience, and partly for fun and promoting a simple minded RTOS, I thought I would help you and write some code to do what I think you're trying to accomplish.

The attached code is a schedule driven state machine that tests every 100 mSec for changing the on-time and off-time for the "heartbeat", as well as drives the beat in 100 mSec increments.

Buttons rb.0, and rb.1 respectively decrease and increase the OFF duration, and buttons rb.2 and rb.3 respectively decrease and increase the ON duration. The LED drive output is rb.7

All quite simple really; the beat duration, it's on-time load value and it's off-time load value are all adjusted independently.

Step through it with Guenther's simulator, and run it single step with she SX-Key to gain a full appreciation of what is going on. Then experiment to your heart's content!

P.S. I have not yet run this code, but I believe it to be OK. I'll check it tomorrow when I get to my bench.

post edit;· ooops... I·saw a couple of errors; hope this now works...check tomorrow!

Cheers,

Peter (pjv)

Post Edited (pjv) : 1/12/2006 5:16:48 AM GMT

ChrisP · 2006-01-12 06:36

Geek,· Here's a start, or at least something to play with in SX/B its not commented yet but I'll try to get some more time on it in the next day or two. Its a bike project so thats high on my list as far as projects go. I havent run it yet, will try to get back to it and take a run Fri or Sat.

Peter, snagged the download on that one too, I can use all the examples I can get, looks like its going to be quite a while before I get a grasp though.

Chris

Heartbeat

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