Gaussmeter Kit Group-Buy

[RedHouse]

Yes, my offer of building an enclosure or any other hardware doesn't have to be part of your group buy kit. Some of you may prefer to build your own. I can make up an enclosure that suits my purposes, and then offer copies of it to any of you who want it.

Sounds good Bruce

[RedHouse]

...I will probably be in.I'd just like to have a ballpark price before I give my word to join....

As it should be automan.

I'll work through Elepro's Mouser parts list in the next few days and get an estimate for parts costs.

I'm busy this 4th of July weekend, but trying to stay tuned-into this thread as much as I can.
(when I'm near a computer, that is)

[spy]

Spy, you get with Bruce and figure out if he can/will make you an enclosure, then let me know if you are in. I already have enclosures for my needs.

Brad, I'm in from the beginning!
No problem if there is an enclosure or not! Just thought that it'll be a great idea if the other members of the Group Buy would like an enclosure from Bruce. If they don't like it that doesn't change my decision. I'm in all the way!

[David Schwab]

Yes, my offer of building an enclosure or any other hardware doesn't have to be part of your group buy kit. Some of you may prefer to build your own. I can make up an enclosure that suits my purposes, and then offer copies of it to any of you who want it.

And Bruce, I certainly wasn't saying we shouldn't use a nice custom case you might come up with! Just that there are a lot of cases available from electronic parts distributors, and was directed to spy, so he would get into the buy!

[RedHouse]

GROUP VOTE NEEDED:

For those who are "in" on this group-buy, go here and post you preference of which display color you would prefer if we buy from Mouser:

NHD-0216K1Z-FS

{EDIT} I liked the "Gray" one at first glance, but after looking at them on the website link below I definately like the white-backlight one the best. Much easier to read, more like a cell phone backlight.

{EDIT} you can look here on their website to see the displays and do a mouse-over to see them w/o their backlight.
Note that not all displays on this webpage are the ones specified for this project only the NHD-0216K1Z-xxx will work for us, but it's cool weblink anyway, check it out!
2 x 16 Characters


BTW; I ordered some A1302 (hall sensor) from an eBay seller out of Korea last night, got them for under $2/ea.

PS: I should be able to finish working through the Mouser list tonight. I have found an offshore supplier on eBay that sells a display module which looks like the one Elepro used, just waiting for a data sheet response, so that is another option if we don't like the Mouser offerings.

[RedHouse]

And Bruce, I certainly wasn't saying we shouldn't use a nice custom case you might come up with! Just that there are a lot of cases available from electronic parts distributors, and was directed to spy, so he would get into the buy!

Same here, I wasn't saying "no" to a case, I was just saying that as for me, I'd prefer to get my own outside of the group-buy.

I would think that Bruce would need an assembled component kit to develop the case layout, so waiting on a case would hold up the whole group-buy.

[spy]

Grey is cool! I vote for Grey.

Great with the A1302, and at a very low price!

[DrStrangelove]

$$?

Guys, A1302 sensors are hardly unobtainium.
I bought 25 of them from Digikey.com a few months ago for ~$1.20 each.

Elepro gives six suggestions for the LCD display, and spec'd them on a
Mouser project manager parts form for us at:
https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=2c947e7457

Don't be put off by the $75 total price -- he gives six choices as to LCD display.
If you choose only one LCD plus the miscellaneous parts, the total is around $27.

Elepro has done a lot of the research and setup for us.
We should take advantage of it.

-drh

[-Elepro-]

Guys, A1302 sensors are hardly unobtainium.
I bought 25 of them from Digikey.com a few months ago for ~$1.20 each.

Elepro gives six suggestions for the LCD display, and spec'd them on a
Mouser project manager parts form for us at:
https://www.mouser.com/ProjectManage...sID=2c947e7457

Don't be put off by the $75 total price -- he gives six choices as to LCD display.
If you choose only one LCD plus the miscellaneous parts, the total is around $27.

Elepro has done a lot of the research and setup for us.
We should take advantage of it.

-drh

don't watch that list in your link.... watch this (post #19) it is more or less the same in your link but better(i don't remember why but i will check again... ) .... the lcds in Redhouse post are right (they are in my list).... don't forget to select "low power backlight"..... I think that it's better rewrite list here....

but..... how many are in the group??

....about MCU:
my offer is 22EURO/each for 10+ order or 20EURO/each for 15+ order (shipping to group-buy coordinator included)

[Bruce Johnson]

I'm still in; gray is fine for the LCD readout.

About the enclosure, yes, I'd rather have the parts kit in my hands before I make one. So, we don't want to hold up the parts kit group buy. I'll just build an enclosure for my own meter, post pictures, and if anyone else wants me to make one for them, they can contact me. It's not going to be anything fancy...but I usually use a metal box rather than a plastic one.

I'm sure most of us can drill holes in a box! I wasn't sure if it needs any special metal parts like brackets, blocks, sensor mounts, etc. That's where I can help any of you that don't have the machinery.

[defaced]

I'm casually in. Meaning, I have to do some research on sensors and the meter range to see if it will work for a possible electromagnet project I might be doing for work. Since I have no concept of how much a gauss is, or how much gauss one thing puts out compare to another, I need to do some leg work.

[Yves]

I've made the gaussmeter designed by Antonio, and it works great for me.Since I've already made it, don't count me in, but here are a few comments that may help.


1/ I've ordered both the LCD with blue backlight and hall sensor from this Ebay store:
Boutique eBay - MIND-TEK : Connector, Resistor, Display LED LCD

I got 2 sensors+LCD and shipping cost for 12.50$ and everything was at my door (in France) well packed within a week. It cost me less than going to my local store just to buy the LCD, not to mention the hall sensor which isn't that common to find. I can say that the LCD is compatible, no problem.

2/ Since this LCD requires backlight, I've replaced the switch at conn2 by a wire strap, and used this switch instead of the push button at conn6: I prefer to have a toggle switch to choose between the normal/peak hold modes

3/ Regarding the size of R1 and its access through the back of the board: I haven't found the matching part, so I have used another one (which I had to slightly bend the pin to fit in). Mine has access through the top, so I've use wires instead of connector to attach the LCD so that I can lift off the LCD to access R1, should it be needed (see pictures). BTW, I haven't used any connectors but soldered wires directly on the board.

4/ I've removed the decoupling cap attached to the sensor. I found it too bulky at the extremity of the probe and since there is no much reason to have massive spikes in there, I thought it would be OK. It works for me.

5/ Regarding the calibration. From my point of view this is a really usefull tool to compare gauss reading between different magnets and assemblies. However, I personnally don't see much point of having an absolute calibrated reading as long as this fall within decent tolerance and repeatabilty which I believe is the case. So I don't mind if this is not calibrated.


Hope this helps

[RedHouse]

...

but..... how many are in the group??

....about MCU:
my offer is 22EURO/each for 10+ order or 20EURO/each for 15+ order (shipping to group-buy coordinator included)

.
.
.
.
The Who's In List: (July 6, 2009 7PM)

7 Definate Participants:
Redhouse
David Schwab
JasonG
spy
firewire
Bruce Johnson
Arndawg56

2 Possible Participants:
automan
defaced
.
.
We need a few more to get the 22-euro/$30.66-USD price break, a savings of $12-USD
(which is down from 30-euro/$41.81-USD of individual ordering)
.

[RedHouse]

Parts Issues and Suggestions:

Going through the parts lists and validating through Mouser I find a couple things need adjustment.

1.) the PIC is a 28 pin chip, the socket that was specified was a 14 pin
(M# 517-4814-3004-CP ...should be... M# 517-4828-3004-CP

2.) the trimmer specified M# 652-3318S-1-203 a 20K trimmer is obsolete, non-stocked at Mouser so I found the Phier 531-PT6KV-10K a good substutute and is available in the originally specified value of 10K, most importantly it IS adjustable from the back via the thru-hole in the PCB.

3.) the resistors specified are 5% tolerance carbon comp resistors, for only a penny more per resistor would the group mind if we changed-up to decent 1% Metal-Film resistors?

4.) Yes the A1302 are not unobtainuim and DrStrangelove mentioned Digikey has them at a current price of $1.37/ea, ...but... I ordered some from an eBay store ....soooo ....I need to know if it's gonna hurt anyone at $1.50/ea?

5.) The M#1055-TA2120-EVX ($2.20) toggle switch specified is "Mountain" brand, I've had bad experiences with Mountain brand switches in the past, they are really cheap-ass, like the mounting nuts are stamped and pressed sheet metal instead of a proper formed and tapped nut. Would the group mind if we changed-up to a decent C&K toggle M# 611-T101-001 ($4.05) I know it's twice as much but it's a much better switch...?

[RedHouse]

...I've made the gaussmeter designed by Antonio, and it works great for me.Since I've already made it....

Wow! thanks for the validation Yves, appreciate you input very much.