Do you have a question? Post it now! No Registration Necessary
Subject
- Posted on
June 12, 2006, 9:44 pm

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

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:

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

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
Sell your surplus electronic components at
http://ozcomponents.com
We've slightly trimmed the long signature. Click to see the full one.

Re: Battery charging contact ideas for H/H device
snipped-for-privacy@woodtech.net.au says...

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.

Think big,
<chuckle>
--
Regards
Mike
Regards
Mike
We've slightly trimmed the long signature. Click to see the full one.

Re: Battery charging contact ideas for H/H device

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?
John G
Wot's Your Real Problem?

Re: Battery charging contact ideas for H/H device
snipped-for-privacy@woodtech.net.au says...

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
Regards
Mike
We've slightly trimmed the long signature. Click to see the full one.
Site Timeline
- » SMD transistors
- — Next thread in » Electronics Down Under
-
- » Detecting the original pitch of the human voice
- — Previous thread in » Electronics Down Under
-
- » Aussies Love EVs ?
- — Newest thread in » Electronics Down Under
-
- » Replacing NiCd batteries in an obsolete Uniden UH-052XR radio?
- — Last Updated thread in » Electronics Down Under
-
- » Wyłącznik różnicowoprądowy
- — The site's Newest Thread. Posted in » Electronics (Polish)
-
- » A solid state replacement for the lowly 2D21 Thyratron tube...(sorry for the On-To...
- — The site's Last Updated Thread. Posted in » Electronics Repair
-