Gaussmeter Kit Group-Buy

[Dave Kerr]

Might it make sense to group buy a couple extra PICs in case one croaks/is defective? Seems coordinating swapping a part overseas to Italy would be bothersome. Or are these chips pretty bullet-proof once the code's loaded in?

[RedHouse]

Ok i'm happy.....

in the last picture it doesn't show well.... but did you have seen in datasheet what's the sensor surface active area? it's important.... you have to put magnet on the right surface of the sensor.... watch my drawing

bye

Yes I got that specification Elepro, in this close-up picture you can see better both the orientation of the sensor (beveled side facing the magnet), and also the little micro-pin-socket lead I made up for this test jig:



The idea behind this socketed sensor lead is, once I get a calibrated known-value magnet to use in the future as a "control" specimen, then I can place each A1302 sensor into this socketed test harness and measure with the known-value magnet I should be able to find the right offset for each sensor if needed .
(this sensor lead is not the lead I'll be using in my final meter, it's just for testing purposes)

[-Elepro-]

Might it make sense to group buy a couple extra PICs in case one croaks/is defective? Seems coordinating swapping a part overseas to Italy would be bothersome. Or are these chips pretty bullet-proof once the code's loaded in?

i test all chip that i send.... i built another gaussmeter just for this.....
certanly if someone put chip in wrong side or if the board has some other problem (bad solder, short circuit, a defective 7805 ecc ecc....) or if someone plug gaussmeter directly into the wall ... then pic can has some problems

in photo my gaussmeter, a gaussmeter built just for PICs test and some PICs.....

[-Elepro-]

Yes I got that specification Elepro, in this close-up picture you can see better both the orientation of the sensor (beveled side facing the magnet), and also the little micro-pin-socket lead I made up for this test jig:

perfect .... excuse me for unnecessary information.....

The idea behind this socketed sensor lead is, once I get a calibrated known-value magnet to use in the future as a "control" specimen, then I can place each A1302 sensor into this socketed test harness and measure with the known-value magnet I should be able to find the right offset for each sensor if needed .
(this sensor lead is not the lead I'll be using in my final meter, it's just for testing purposes)

great idea....

[RedHouse]

...If we get to the point of needing a few more orders to make Elepro's price breaks, I'd be willing to spring for an extra one or two kits (which I would assemble and sell)....

Now's the time to speak-up for shure, we're getting close to the Last Call.

Might it make sense to group buy a couple extra PICs in case one croaks/is defective? Seems coordinating swapping a part overseas to Italy would be bothersome. Or are these chips pretty bullet-proof once the code's loaded in?

I'm not shure any swapping will be in the future, there was no implied guarantee with these if that's what you mean. If you mean simply aquiring a new PIC if your's goes T.U. then yeah, now's the time to speak-up for shure.

It's too early to go into details, but I'm communicating with Elepro off-line regarding future kit offerings, but know that it wouldn't be realized at this kind of bare-bones price point. This bare-bones price is because each participant has to invest sweat-equity, assembly, wiring, and work out the housing specifics. A "Ramsey" style kit where you solder-n-go will cost more, and obviously a fully assembled unit would too, but either case would still be well under the cost of a current production hand-held gauss meter.

[RedHouse]

i test all chip that i send.... i built another gaussmeter just for this.....
certanly if someone put chip in wrong side or if the board has some other problem (bad solder, short circuit, a defective 7805 ecc ecc....) or if someone plug gaussmeter directly into the wall ... then pic can has some problems

in photo my gaussmeter, a gaussmeter built just for PICs test and some PICs.....

Elepro, check your PM's

Also, with regards to the various skill levels of participants in this group-buy, and since inserting the PIC wrong can blow it out, I think you and I should agree on how to insure they are in working order when shipped.

Will you be testing each one prior to shipping to me? should I also be making up another test fixture and test each PIC before I ship it out?.

[Dave Kerr]

I'm a bit of a rube when it comes to this stuff, was just wondering aloud whether it made sense to have a spare kicking around stateside somewhere. If there's a high likelihood that if this thing doesn't work it'll be due to my error and not a defective PIC I'm cool with that.

[David King]

People assembling this kit should probably read up on working with C-mos components and how to avoid static discharge when they are handling them. It should not be much of an issue in summertime with the humidity but if you wear plastic shoes and have wall to wall carpeting then I can see where there could be tears.

[Arndawg56]

VERIFIED....IT WORKS.

I popped the PIC into the socket, stacked the two boards and powered it up.

At very first there was nothing showing on the disply, then I remembered what Elepro had said about tweaking the trimpot if there is no display, so I did and sure enough the display fadded into view.

I grabbed a pickup from a box on my bench which happened to be a SD Alnico-II Pro (APS1) and the meter measured the poles (in Ph mode) as follows:

E=781g
A=769g
D=789g
G=797g
B=765g
E=757g

Here is a picture of the test unit just after switching on, after the meter boots-up it zero's itself then looks like this:



Here is the test unit measuring a Seymour Duncal APS1:



Nice work Elepro, my first impression is very nice, it works right from the start, and as advertised.

I say if they work, go ahead with the "last call" and order everything up. Can you maybe make arrangements to compare it to a commercial unit while the parts are being shipped. I would prefer to get mine as soon as possible. We all agreed to the purchase these before Red House offered comparing it to the commercial unit. Besides, you never know how long it might take to get a meeting set up to agree with Red House's and the guy with the commercial meters schedule!

[RedHouse]

I say if they work, go ahead with the "last call" and order everything up....Can you maybe make arrangements to compare it to a commercial unit while the parts are being shipped....Besides, you never know how long it might take to get a meeting set up to agree with Red House's and the guy with the commercial meters schedule!

I'm trying to make arrangements as we speak (or as we post).

As you all know, this time of year is quite hard to sched stuff because of vacations and summer things, office party's, B'days, weekends with family etc.

I have a couple hours this Sunday, and either day next weekend left open to do it, after that I'm booked-up until the second week of September ....unless something breaks loose off my schedule.

Funny, seems we drifted away from holding off last call until I could recieve, build and validate the unit, and now we're waiting on further assesment?.

[defaced]

Funny, seems we drifted away from holding off last call until I could recieve, build and validate the unit, and now we're waiting on further assesment?.

When the PIC arrives and I get the verification-build assembled and running, how many in the group-buy would like us to call that good and proceed with Last Call ...or... would the group prefer to wait until I can get the verification-build over to Wolfe or Jason to test it up against a commercial unit.

Um, unless I missed something, it looks like it was your idea, and I think a good one.

[RedHouse]

Um, unless I missed something, it looks like it was your idea, and I think a good one.

So it was, thank you Mike.

UPDATE:
We'll be going into an in-definate hold on the group-buy.

I'm currently working at scheduling a date/time to validate against a commercial unit. I have a narrow window of opportunity in the very near future, for me this Sunday is open but I have not heared from Wolfe or Jason regarding this weekend and as today is Friday I'm assuming this weekend isn't going to work out. Next Saturday and Sunday are open with me, but if that fails it's looking like the second week of September will be the next available time to sched on my part.

[RedHouse]

I'm a bit of a rube when it comes to this stuff, was just wondering aloud whether it made sense to have a spare kicking around stateside somewhere. If there's a high likelihood that if this thing doesn't work it'll be due to my error and not a defective PIC I'm cool with that.

Would be good, maybe you should be down for 2.

[David King]

I don't care about a calibrated unit as all of my measurements will be relative anyway. Even 10% off is plenty good since the Gauss units are kinda meaningless in the grand scheme of things.

[automan]

Redhouse, can I go ahead and send you cash for mine? I am about to relocate my family, school, and life across the country from Boston to Nashville. I would rather go ahead and get the money out rather than have to explain to my wife why I am spending money on this after the move when things wont be quite as easy as they are now (at least for a time.)