IGSL

[6666]

Hobbyking is the place to buy R/C gear
dont discharge your lipo's too far for long life

[kliner]

I use Lipo and Life packs, even the Lipos made for the Txs will do, we're only pulling around 100ma max

[der_fisherman]

Using LIPOs can be dangerous!!

Also - what are folks using for battery power? I've been eyeing rc plane/airsoft LiPo packs. I presume 11.1V will fit the bill, am I correct?
Any ideas whether the discharge rate is a worry? 10C or above should be fine, right?
Your naive friend,
lunar underground

Please also wait for answers from people like Simon, Don and others, but my take on the subject is that you may:-
a) reduce the depth slightly as the 12 volts is used for the Tx coil on the IGSL if I remember correctly.
b) May also slightly reduce the volume as it is also used on the loudspeaker output.
c) Battery life may not be as good as you wish, though as I don't know exactly what capacity batteries you are thinking of using, that may not be true. This will also depend a little on the 8 volt regulator used to some degree.
d) I would almost rather to have a stick of dynamite in my MD than a LIPO battery, check out this video:-
http://www.youtube.com/watch?v=z3o_2mwRPdw
Buy the Liposack if you decide to still use them, it may reduce collateral damage somewhat.....
As the circuity stands, it really needs 12 volts on the button to my mind.....I would rather use NiMH batteries and get a nominal 12 volts as its simpler and far less dangerous in some situations, but each to his own.
I am actually investigating (somewhat slowly!) about using 18 volts to improve depth and loudspeaker volume....once mine is working as I wish with 12 volts....
Regards
Andy

[kliner]

A 3s lipo is already flat at 11.1 volts (10% left) it is 12.6 volts fully charged, look at these values

100%=12,60
90% = 12,45
80% = 12,30
60% = 12,00
40% = 11,70
20% = 11,40
10% = 11,10

You can see that there is no problem when using an 8Volt regulator.
Lipos have a lot of advantages, high power per weight, very high current draw, up to 30c (30 times the capacity, 2000mah you can pull 60amps) and high voltage per cell.
Of course you have to have a special charger for them but they are fairly cheap, I have had a lot of experience using these batteries in fast electric model aircraft.
In my opinion they are just what is needed for PI detectors

[kliner]

But it must be said that if you short them out or you overcharge a cell or they fall from 200 meters up they will catch fire!

[bc777]

Hello!

Thanks for this project Ivconic.

I have one question to the guru.

Do I have to meet the nominal value 22nF, 220nF, 470nF to within 1%,
or can be placed with a larger deviation,
only to meet the accuracy in both channels?

For example: C14 = C26 = 212nF, C27 = C39 = 225nF.

What are the biggest deviation can be used to avoid poor
performance device?

Thanks.

[golfnut]

I use 3 lipos = 12v

IU also cut the 8v from Tx osc and run it from 12v for the additional Tx signal

No problem

[lunarunderground]

First success

I just powered up my board for the first time. I'm still waiting on my 5 pin connector, so my testing was greatly limited, but at the very least, I've got 8 volts (well, 7.93) getting to every spot on the board that it should. I'm not getting -6.2v at the other points, but rather +0.69 - which I presume is a product of not having a coil in the mix.

The big triumph: nothing blew up. Visibly, at least.

I need to do more research on the sens/reject pots - getting some unexpected voltages - but I'm nearly done reading the IGSL thread (spent 8+ hours straight reading and taking notes last night) then on the the TGSL thread. I thought I'd work backwards. I don't know why.

Thank you all so much - I would have never had the confidence to embark on something like this without a resource like the one that is provided here.

Lee

[lunarunderground]

... and thanks for the battery input from you all. I am in fact slightly scared of Lipos now...

[simonbaker]

I just powered up my board for the first time. I'm still waiting on my 5 pin connector, so my testing was greatly limited, but at the very least, I've got 8 volts (well, 7.93) getting to every spot on the board that it should. I'm not getting -6.2v at the other points, but rather +0.69 - which I presume is a product of not having a coil in the mix.

The big triumph: nothing blew up. Visibly, at least.

I need to do more research on the sens/reject pots - getting some unexpected voltages - but I'm nearly done reading the IGSL thread (spent 8+ hours straight reading and taking notes last night) then on the the TGSL thread. I thought I'd work backwards. I don't know why.

Thank you all so much - I would have never had the confidence to embark on something like this without a resource like the one that is provided here.

Lee

At least hook up a TX coil (any choke around 6 mH should do) if you want to measure voltages on the PCB so your negative supply is correct.

Regards,

-SB

[6666]

What Kilner said
for long life

11.1 volts is safe , 11.5V is Even safer, any open cct voltage above 3.7 volts per cell is safe.
going below 20% capacity, is not considered a good thing for the lipo's in the R/C world

You will get lots of hours detecting before 11.1 volts with a 3000maH lipo
I will try and take some pictures of some of my puffed Lipo's

[lunarunderground]

I have no enameled wire around so I was relegated to choosing from a few coils from an old laptop. Fooled around for a bit, but wasn't able to get much closer than about 1.2 Hz. With more experience I'm sure I could do it, but I'm blazing new trails for myself here so it's slow going. Got three long shifts at the hospital to carry me through the end of the week and the connector should be here Friday - so I may just have to wait at this point.

In regards to enclosures - the 1455 hammond series is what I think I'm going for - the 160x103x30.5 is tempting me, but I fear it may be cutting it too close on the height. With an appropriately placed speaker, crammed in front pots, external battery ,and an 1/8" jack instead of 1/4" for headphones (which I never use anyway - I'm with you Ivconic) it looks like it would work. Has anyone tried it? All the pics I've seen on here look to be the 54mm height enclosure...

Thanks again ...

[bernte_one]

hello,

here last one i have made today.
http://www.youtube.com/watch?v=3SPua...1&feature=plcp

regards bernd

[lunarunderground]

It works!!!!!

Not well, but it works! Working with 13.92 Hz and 6.88 Hz with an 8 inch 5 pin Tesoro coil. Close enough for jazz. Negative voltage is half (well, double) what it should be at 3ish volts - that's the first issue for me to tackle - let the research continue - but I'm tickled pink that she fired up at all. Thanks again to you all!

And nice work bernte!

[lunarunderground]

... kHz that is ...