STAMP Circuit Needed - Paying $

Hi:

I in need of someone to design a fairly basic circuit explained below. If you can design it, please email me a price quote. I think a programmed STAMP type circuit is needed, but feel free to quote whatever you think would work best for the requirements listed.

Here is what I need:

  1. I plan to use 2 photoelectric cells and a stepper motor. Lets call the photoelectric cells X1 and X2.

  1. The circuit needs to constantly compare the voltage between X1 and X2 and if X1 is higher than X2 then move stepper motor counterclockwise. If voltage X2 is higher than X1 then move motor clockwise. If the difference between voltage X1 and X2 is almost the same (within a certain range) then do nothing. I am not sure what the proper 'range' is yet for my needs. So this 'range' must be able to be adjusted by me as the project progresses.

If you can design such a circuit and explain to me in English how to build it (I can't read electronic schematics that well) then please email me a price quote.

Or, if you know where I may find such a circuit already designed, or if you know someone who can design it, such information would be greatly appreciated also.

Thank you,

Joe Gayetty Reno, PA snipped-for-privacy@gmail.com

Reply to
Joe
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I'll stress what Nick has to say about experience: Get someone who has actually _built_ something that _works_, preferably before they went into their EE program. Having presided over lab classes as a grad student, and having hired and trained engineers, I can vouch for the fact that you can get straight-A's in an engineering program with hard work and precious little practical ability. I went into my EE program with fairly advanced hobbyist skills so I came out ready to land on my feet and start running at my first job, but there are plenty of new graduates who would grab the hot end of a soldering iron if you let them.

Doing this remotely can be done, but you have to sign up for the overhead (possibly involving shipping your motors, sensors, etc., around). There are plenty of people on this list who will assure you it can be done, and it can. On the other hand I'm sitting 5 feet away from some client equipment that I couldn't work without, and I'm working with another client who's 2000 miles away and held back right now because his equipment really needs a laying on of hands and I can't just drive over and do it.

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Tim Wescott
Wescott Design Services
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Reply to
Tim Wescott

Hmm... I suspect that Jim Williams hasn't personally built most of the stuff he's designed recently, yet I'd certainly still hire him!

You have a point, but I'd say you have to phrase it more along the lines of... after the client builds two prototypes (at his own expense), the contractor will demonstrate two of them working.

That's where simulation comes in. If you have good enough models, a working simulation typically produces a working product. This is _especially_ true in digital design -- I know several engineers who've written thousands of lines of VHDL or Verilog code and never even _seen_ the product it ended up in.

For the circuit the OP requested -- delivering two working prototypes would be reasonable, but it's going to be that much more money the OP will have to pay (and I have a suspicion he's doing this on a 'hobbyist' budgement rather than a Real Business budget).

---Joel Kolstad

Reply to
Joel Kolstad

I had a favorite uncle who inspired me to be an EE. He used to be a project manager for Boeing; when he interviewed prospective electrical engineers he'd casually hold out a (cold) soldering iron to the candidate business end first and say "here". Anyone who didn't carefully reach _around_ the tip to grab the handle in the approved manner didn't pass the test.

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Tim Wescott
Wescott Design Services
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Reply to
Tim Wescott

No, he wanted folk who were smart enough to not grab a soldering iron by the tip when they didn't know whether it was hot or not.

Sometimes he'd just ask if they knew what it was.

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Tim Wescott
Wescott Design Services
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Reply to
Tim Wescott

Google some solar power sites. They use a similar system for sun tracking.

If you're as experienced with electronics as you appear to be, you probably need a local collaborator. A long-distance circuit designer will probably result in much expense and grief for you. mike

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Reply to
mike

A picaxe-18x chip would do that handsomely and cost much less than the stamp. You will find stepper motor routines, driver circuits, etc. on the Internet.

Reply to
Charles Schuler

So he wanted people who would follow the approved "rules", whether the iron was hot or not?

Reply to
Spehro Pefhany

"Joe" wrote

When hiring someone to design electronics or software the client needs the contractor to build two units (minimum) and test both thoroughly.

Why must the contractor build and test two?

o An untested design _will not work_ , excepting by accident.

o The buyer does not have the knowledge of the design to enable him to get it working properly in a cost effective manner

o Further, the client does not know how it is supposed to work - the original specification was a dream - the engineering model is the interpreted reality and we all know how well reality matches our dreams.

Why two?

o One to stay with the developer so that a test bed exists for - duplicating problems, - changing the design at the client's request - adding features.

o One for the buyer to test and approve.

If, in addition, the client is naive in the required technology, then purchasing just the design and having the client take it from there is a sure disaster.

Drawing the first schematic and typing the source code is 10% (the most important 10%, it is true) of the effort it takes to get the design working and documented.

Buying 10% of a design job is like buying 10% of an automobile. It won't get you anywhere and you will have wasted the money you paid for the 10%.

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Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer:  Electronics; Informatics; Photonics.
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Reply to
Nicholas O. Lindan

And furthermore:

(Dodges hail of rotting tomatoes.)

If you are going through with your original plan, I would suggest dealing locally. With someone who can come over and see what is going on and how it needs fixing.

Check the local university and hire a Junior year EE student. They are usually smart, they work cheap (

Reply to
Nicholas O. Lindan

"Tim Wescott" wrote

Grab it many times, in fact -- six-sigma statistical significance, you know.

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Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer:  Electronics; Informatics; Photonics.
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Reply to
Nicholas O. Lindan

Not plesant!!! And by the way I can note that hang-overs is a strange (evil!) thing: Your reflexes /can/ be good enough to grab a falling object. But they might not be very efficient in letting go again - which might lead to additional pain (adding to the hangovers)...

/Anders (who will deny any claims of the above facts being based on personal experience ;-)

Reply to
Anders F

"Spehro Pefhany" schreef in bericht news: snipped-for-privacy@4ax.com...

The polite way to hand someone a soldering iron is to hold it by the hot end yourself.

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Reply to
Frank Bemelman

Of course you would never let an potential imbecile touch your soldering iron... ;-)

/A

Reply to
Anders F

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