MMP saga continues

[Tibuck19]

Hello ones again all, yet a new problem, All of a sudden a new Boo boo on my minipulse, when I swing the coil over a coin or any metal object for that matter, the close to the coil it is the lower the Audio gets , almost like the audio just drops out and the speaker seams to grunt like as if the current was going the wrong way, Any clues?? . Also I have an other question while im at it, I seen a video of the stages of setting up the minipluse, the man seems to use TP10 as the ground for the oscilloscope probs, When I try to use the Tp10 the detector shuts down as if I was causing a short.

[Tibuck19]

PROBLEM SOLVED , Bad 555IC replaced on of the two and all is right with the world again, I would still like to know about the Probe ground thing though.

[homefire]

I was going to go with a Battery issue.

[Tibuck19]

I was going to go with a Battery issue.

Its out of its case on the bench hooked to a bench power supply , Defiantly wouldn't of been that, but one never knows hahaha You built a MMP to right homefire? whats your depth on on it ? With a 10 inch mono loop coil made with 22 gauge @ 360 uH that I know its good, and a 10inch coil made with 25 gauge @ 422uH I cant get more then 7 inches on all Usa and Canadian coins and its scratchy at best, Does that seem right to you ? even my SurfPi gets more depth then that.

[green]

Its out of its case on the bench hooked to a bench power supply , Defiantly wouldn't of been that, but one never knows hahaha You built a MMP to right homefire? whats your depth on on it ? With a 10 inch mono loop coil made with 22 gauge @ 360 uH that I know its good, and a 10inch coil made with 25 gauge @ 422uH I cant get more then 7 inches on all Usa and Canadian coins and its scratchy at best, Does that seem right to you ? even my SurfPi gets more depth then that.

Try connecting scope common to TP10 using a battery instead of the bench power supply.

[homefire]

Not built it as of this time . Have two PCB and all parts set up to go. I would try a basket coil on that thing. This is a 5" I'm playing with for the Barracuda. Pretty much same requirements.

5 inch form
24 SWG copper
Unknown Turns
410uH
1.4 Ohms

[Qiaozhi]

]I would still like to know about the Probe ground thing though. [/B]

Its out of its case on the bench hooked to a bench power supply.

That's the problem ... "hooked to a bench power supply".
If your scope and the bench power supply both have their common line connected to mains Earth, then they're shorted together. Since the MPP uses battery positive as 0V, you are shorting the supply lines via earth.
I've just checked continuity from my scope's ground to earth, and there's a connection (as expected), but my my bench power supply has outputs that are isolated from earth. Therefore I am able to use my scope on the MPP with a bench supply.
So, either connect your MPP to a battery pack, or buy a better bench supply, and the problem should go away.

[Tibuck19]

That's the problem ... "hooked to a bench power supply".
If your scope and the bench power supply both have their common line connected to mains Earth, then they're shorted together. Since the MPP uses battery positive as 0V, you are shorting the supply lines via earth.
I've just checked continuity from my scope's ground to earth, and there's a connection (as expected), but my my bench power supply has outputs that are isolated from earth. Therefore I am able to use my scope on the MPP with a bench supply.
So, either connect your MPP to a battery pack, or buy a better bench supply, and the problem should go away.

Thank you I will try that , My bench top power supply has the yellow output, would that be the earth output your using ? I will do the Battery pack. Thanks George and Green that had also mention this. reason I was asking was because I have a hard time triggering with , scope on TP3 and when I do get it to trigger is shakey.

[Tibuck19]

Not built it as of this time . Have two PCB and all parts set up to go. I would try a basket coil on that thing. This is a 5" I'm playing with for the Barracuda. Pretty much same requirements.

5 inch form
24 SWG copper
Unknown Turns
410uH
1.4 Ohms



[ATTACH]39970[/ATTACH][ATTACH]39971[/ATTACH]

Have you made the Case for the Barracuda and MiniPulse Plus yet? If you have access to a 3D printer I would be more then happy to share the STL files for the case I made, Later on this morning I will Link a few photo on the this thread for you to see what it looks like, It pretty nifty with 3X 18650 battery pack imbedded in the back cover. both the BABA and the Miniplus use the same case with only difference being the faceplate.

[homefire]

I do not have a Printer but may have access to one. Yes, Please post what yours looks like.

[Tibuck19]

I do not have a Printer but may have access to one. Yes, Please post what yours looks like.

four parts one of which ( white handle gripper ) is glue on to the main case. like I said the main faceplate/ board holder is the only difference from the Baracuda and the Minipulse plus I made mine for what I use, the holes for the pots are for normal 8 mm shafts and the light hole is for a 5mm led, I only used two pots but I can add two more holes for a 4 pot config, also the front cover has the hole for a IP68 Connector which is what I use to plug the head set and some hole size in back cover for the Coil coax.

It was easier to make a drop box link for the photos, Let me know if you can see them please. https://www.dropbox.com/sh/5thzm8mxu...2mue-41Ta?dl=0

[homefire]

Cool Stuff. Bounty Hunter Look a LIKE. Good deal on the 18650 battery tray. What was the cost on printing those ?

[Tibuck19]

Cool Stuff. Bounty Hunter Look a LIKE. Good deal on the 18650 battery tray. What was the cost on printing those ?

Hahah im not sure if that's an insult or not , I couldn't tell u what a bounty hunter looks like , it does look somewhat cheap and when I designed it, I made it to be easy to print, and so everything would fit nicely. I have to admit the Big case part I printed fast with a big 0.8 nozzle and I had to re layer with Abs slurry and sand the big extrusion lines to make it look somewhat nice. but that didn't take long at all. The batteries are always the biggest head aches to design around. the first case I made was smaller, but the battery pack I had previously made didn't look nice and was not permanently attached which was not good for me.

To answer Cost : Its all printed out of ABS , At 25$CAD average price I pay my rolls, in total it cost 12$CAD I doubt I would be able to find something pre made that would fit nicely at that price.

[homefire]

No insults intended it just happens to look like a bounty hunter housing. Yours is Quite Nice. The Bounty Hunter housings are more then a tad oversize.

[Tibuck19]

No insults intended it just happens to look like a bounty hunter housing. Yours is Quite Nice. The Bounty Hunter housings are more then a tad oversize. [ATTACH]39981[/ATTACH]

holy molly that does indeed look a like huh ! loll looks like im changing the design once more hahaha I Don't know about size, mine still looks rather big to me at 150mmx130mmX75mm or 3"X5"x5 3/4". maybe ill make a box that will clip under the handle linked my a wire to a second better looking shape box thing the will clip on to that will house the led and control knobs only so that part can look more space age.