Questions on Sniffer XR-71 build

[Gunslinger44]

Hey guys, I bought one of Crazy-Tech's built XR-71 boards and a 1 meter coil. I have not built a MD before (though really I'm just building the control box and coil frame), so a couple questions:

1) What is the best kind of piping to build the coil frame (I seem to see a lot of grey conduit PVC)?

2) Is there some kind of spray shielding I should put on the box? Outside or in?

3) Machine runs on 12v power, does an 8-cell AA (1.5v x 8 = 12v) work for this, I would assume so, but I am not an electronics guy.

4) I'm building the box from bamboo and poplar, it will be beautiful, but is there any reason why not to use such? It will be fully waterproofed

I'll post up pics when I'm done, its going to be beautiful, hopefully work just as beautifully

[dbanner]

Did you say bamboo? Am I missing something here?

[dbanner]

Better to use aluminum box.

[dbanner]

With such a box to house the electronics, you will have shielding from electrical interference. You need to ground the box and the pots. You can cover after with bamboo finish if that is your desire. This to me is best approach rather than dealing with messy spray etc.

[dbanner]

8 double A batteries would work but better to use larger capacity rechargeable 12 volt battery that save cost in long run.

[dbanner]

Use 3/4 inch PVC for frame of coil. There is much information here on forum for coils.

[kt315]

do not run around the bamboo. all info in this thread http://www.geotech1.com/forums/showt...03-Delta-Pulse
read from begin.

[dbanner]

Bamboo? Very nice

[Gunslinger44]

dbanner, thank you. As for shielding, I have copper foil tape, and aluminum tape, would either of these work, just line the inside of the box with it? As for the foil, and metal of the control box, will the 1meter square coil make noise and sense the control box as a target? That was part of the reason for me building it from wood

[kt315]

pls do pics and upload. would like to look on your job by your eye (lol!) i must know how bamboo is good.

[Tim]

My crazy-tech xr71 is in a plastic box, no shielding and no problems whatsoever. I made the coil from a 48x30 square plastic tray with 3 rounds cat5 cable, end joined,(tapped at 22 turns) with last 2 rounds open-ended. With proper adjustment it absolutely hammers an Oz 20c piece at 40 cm and an aluminium can at 1.2m. I used 3x secondhand 18650 batteries, but will change it to 6 new ones, as now the red LED(low bat) is on constantly.
I just measured the coil.
7 ohm coil. 11 ohms to box (through RCA cable).
As for inductance I am unsure, as my kit meter says 550uH and myBM4070 multi-meter says 360uH
The 4070 seems correct when I measure a known 1mH choke, but these figures seem to fly in the face of suggested parameters...
Two more chinese meters didn't work at all....

[dbanner]

I'm sorry Tim, but that thing with the square coil has to be the ugliest homemade I've ever seen. The one next to it looks good.

[dbanner]

You can put circuit board in any box you like, even in a turtle shell if that's your desire. The difference is what is RECOMENDED as best practices here on forum. Aluminum box.
However, you can also use wood box or plastic box, but best practices dictates that you provide adequate shielding otherwise don't complain when yo run into problems with EMI. Yes you can use copper for shielding, so long as it's grounded. Also ground the pots chassis.

[dbanner]

All required info on Delta sniffer is here on forum, read read read....

[dbanner]

Search for pics album here on forum or look through the attachments on Delta pulse thread for pictures of project