silverdog pi

[marburg]

Hi first time on here just built silverdog pi thought
it went ok untill i conected my test coil of speaker wire
it was picking up pliers and silver and large coins then i noticed a buz
had a figit round it was the mos-fet getting v hot
disconected the coil and it stoped getting hot
so it only gets hot with the coil conected
looked for a short on solder joint all ok
can anybody help please

[WM6]

Did you measure your coil on inductance and resistance?

[marburg]

Dont know about inductance but the resistance is 00.3 the coil is about 4 inch six turnes
of some speaker wire i had its about 4 mill thick yes you guest it dont know a lot just enough
to get me in trouble

[WM6]

Six turns at 4 inch coil diameter?

This is way to few.

At 4 inch coil diameter you need thirty-six or even forty-six turns of 0.4 to 0.5 Cu enamelled wire, not six turns only.

[Davor]

You'll need some 25-30m of some insulated wire on just about any kind of form or shape to get you going.

[marburg]

Thanks bought some wire made 250mm coil works a treat now to put it all together
thanks for your input

[marburg]

Hello back again got the silverdog working but want to try diferent coils do you
have any info on basket or pvc wire wound coils
getting strong signal upto 150mm with faint signal upto
200mm with my 250mm enameled wire coil with just aluminium tape
rapped around it and just jumper cabled to the pcb.
When i chose the best coil i will use guitar amp cable from coil to board.