Battery charging contact ideas for H/H device

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Hello,

I am working on a hand held device containing a rechargeable battery.
When not in use, the device will be placed in a charging cradle /
holder. Charging current is only a few tens of milliamps. I am looking
for a few ideas on how to make the spring loaded connections between
the cradle and the device. I have searched through quite a few
catalogues but have not seen anything suitable as yet.

Maybe someone has overcome this previously and would care to share
their experiences with me? I am open to all ideas.

Andy


Re: Battery charging contact ideas for H/H device


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Maybe something like the "Pogo" pins used on PCB bed-of-nails testers?
Farnell have them.
How about an induction coil that doesn't need contacts?
Is this for production volume?

A cheap and somewhat crude solution would be two banana plugs sticking
up out of the charger box which mates with recessed or low profile
banana sockets on the device. That will hold the device securely up in
the air too, no "cradle" required. Some force required to sit it down,
but serves a dual purpose.
Using 2mm banana plugs will save space too.

Dave :)


Re: Battery charging contact ideas for H/H device



David L. Jones wrote:
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Hello Dave and group,

Thanks for the replies so far. I forgot to mention the source for the
charger will be DC only (from a vehicle). This may complicate the
induction idea somewhat. I haven't looked into this fully but maybe
there are dedicated devices to achieve this without too much  extra
engineering?

At this stage only looking at low volumes. I will investigate the 2mm
banana plug idea.

Thanks,

Andy


Re: Battery charging contact ideas for H/H device



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Another possibility is to have two side contacts (one on each side)
that contact through wipers when the unit is put in the cradle.
Should be fairly easy to do and self cleaning.

Alan

--
Sell your surplus electronic components at
http://ozcomponents.com
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Re: Battery charging contact ideas for H/H device


snipped-for-privacy@woodtech.net.au says...

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One transistor oscillator and coil - little mtp3055 would be ideal
and transmit more than enough power, dont even need a core, air is
fine, full bridge in receiver with resistor and a zener would prob
suffice.

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Think big,

<chuckle>

--
Regards
Mike
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Re: Battery charging contact ideas for H/H device



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You could try looking at some of the bistro food places that have radio
pagers for when you food is ready.
They seem to be quite innovative.
Just stack the pagers  in a cradle and they charge up thru the lower
ones.
They seem to be custom made so that may be a problem.
There are several variations and you could try the food at the same
time.
--
John G

Wot's Your Real Problem?



Re: Battery charging contact ideas for H/H device


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www.idinet.com

look at their battery connectors

Cheers
Terry

Re: Battery charging contact ideas for H/H device


snipped-for-privacy@woodtech.net.au says...

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If you are only looking for a really small current, then why not
just ordinary induction, no need for any exposed pins, you dont
even need a moulded cradle, just sit the h/h device on a pad and
let magentism do the rest ?


--
Regards
Mike
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Does it need a cradle - can it possibly be mounted directly into the cig.
lighter? Like the removable / low cost hands-free phone jobbies.



Re: Battery charging contact ideas for H/H device


The best way is to check out cordless phones.

Basically the base as two horizontal bars that can be depressed down, and
the phone has two horizontal bars sticking out of it perpedicular.

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Re: Battery charging contact ideas for H/H device


Rare earth magnets could provide both the contact and the cradle/attachment
Alternatively, could you get a solar cell in there?
Wayne
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