Carls fluxgate magnetometer kit Scl007 newbie build

[Cech]

Hello,
i just recently ordered this magnetometer kit and i will try to assemble it myself. I dont know much about electricity, but i am good at mechanical manufacturing. I will post my progress and i will certainly need some help with this. So please bare with me.

Either i build it or i will give it up.

Here some ideas:


1/ piezo speaker, 10LEDs voltage graph bar, and volume control will be installed on the top of tube with sensors heading down. Battery and circuit board will be in backpack. Considering low consumption display.

2/ im considering to use sign bit function from scl007

3/ tube will be around 1mtr long, considering insulation /wood,rockwool

[nelson]

Hi

I also own this mag.
When i tested it on my lab it shows very good sensitivity, but after i mounted the unit on a box and try to give a good tune for the two fuxgates, the mag shows poor and confusing detection.
However, this is just a bad calibration of my fluxgates.
Circuit assemble is very easy, just keep an eye on fluxgates separation, orientation and good calibration.
Regards
Nelson

[Cech]

My kit is coming in couple of days. I think it will be most important to get those two sensors aligned near perfect or else further tune up and calibration makes no sense. It will be challenge.
I have idea to get it in between tense tygon tubing that i have at work. It is very flexible material and has lot of friction with glass. I assume fgm3 are glass. I decided to try align them with use of flexible tension in the air. Then im thinking to put them tensioned in wax bath which can be upto 65C(hope sensors can undergo this temperature outside operational. And then glue them together with acrylic sticks c.3x5mm and gorilla glue about half way around sensors. After that i will use two rings to set bottom sensor head down solid and one ring near bottom part (head) of top sensor. Then three nylon screws for adjustement. Will see how far will i get with it.

[Cech]

The sensor has been made with a cylindrical form in order to facilitate the overwinding of external feedback coils.Alternatively, it can be readily inserted into a separately fabricated coil on a tubular core.
As a simple guide, for example, a single layer of 0.2mm wire ( 0.25mm overall say ) wound over 60mm of the sensorlength will give the equivalent of 4000 turns/metre. Since 1 oersted is approximately 80 ampere-turns/metre, such awinding will produce a field of around 50 oersted/ampere. Thus with up to 100mA flowing it is possible to offset fields of±5 oersted, increasing the range of the sensor by x10. Negative feedback also brings all the usual benefits of improvedlinearity and stability, of course.

-i read somewhere that f/b pin is useless in this kind of gradiometer
But still
- would it be handy to make external winding just for sake of better range/stability?
I understand that in order to make it i just have to wind 0.2mm copper wire 250x for 50mm and then connect it to f/b leg. What do i do with other end of wire? I assume i should close that loop somehow.

[Cech]

Here assembly for initial sensors alignement

[Cech]

So i received kit! It is great. Fatquartersoft guys included all parts drawings nicely packaged with all description. Here picture.
I ordered polycarb tubings and nylon threaded rod. Now im goig to learn some circuitboard soldering on youtube i decided not to mess with wax and air alignement.. Just tubes and spacers. Maybe some resin work.

[Cech]

So board soldered. Great experience.

[Cech]

Also

Also ordered some pots, button and leds. Stillneed ribbon cable. Bought 24 gauge intercom cable 4 conduct which sux. Pipes coming next week. Also need header sockets. Also had to resolder mosfets. Put them bad way

[chemelec]

Curious, What is the Expected Sensitivity Depth of this instrument?
Such as a 4 inch diameter water pipe?

[Cech]

So today i switched it on for the first time with all basic parts soldered. Without any calibration switched it on, and got sensitivity for small maybe 1x5cm, pretty thin kitchen metal blade with plastic handle at approx 20-30 cm distance hearable. Also made mono jack 3.5 connector with little resistor for audio into ipad/iphone. Getting polycarbonate tubes and nylon screws soon.

[Cech]

Test was done in the middle of kitchen equipment. So starting frequency was little higher( maybe like car running idle).

[Cech]

So sensors are aligned, everything is almost done. There is 5/8-3/4 polycarb tubing 3' long with sensors in and 4 spacers around. All is inside 3/4-1" polycarb tubing with 4 nylon bolts on top for alignement.(need to make them nicer). Tried to connect jack to ipad and run spectrogram. Everything works fine. Just starting frequency is little to high i think. Tried to calibrate in middle of livingroom and after calibration there wasnt much change in freq in open air before i went closer with metal kitchen knife. Sensitivity seems to be pretty weak yet. Still about 20-30cm around sensors. No sensitivity in middle of tube. Waiting for better volume and threshld pots. I think when calibrated outside without field interference it will be better. Just dont know what starting frequency should i expect after calibration.someone knows?


here pics

[Cech]

Hi guys so everything looks good. Almost ready for field test.. Now i have two issues..

1/ i want to set leds between scl007 and dac. I bought 1.8v leds. I dont have voltmeter(cuz im newbie) so i dont know what kind of resistor do i need. I tried to just connect a led to scl pins with ground and also to sign bit pin and it looked fine without resistor. Im just worried that itslifetime may be very short if without resistor.

2/ in the corner of pcb there are two holes for additional speaker or jack. I connected jack and it doesnt work at all. It only works in first speaker position.

I am very happy that without any knowledge i was able to make this my first succesful electronic device kit and i learned so much!

[Cech]

Here leds i think here electronic gurus will find it entertaining

[Cech]

So it is completed. It is nice to see how 1s and 0s are running digital to leds. Didnt use any resistors hope they will hold. Sign bit led works wierd. Treshold doesnt affect leds.
This project is great documented and dummy proof. Thanx a lot carl and fatquarter software for all parts and manuals. Here some pictures. In weekend i will put some insulation and put whole probe into other final tube where on the end all controls will be mounted together with leds and speaker
thanx for great documentation for this project