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-- Work Visor Charging Cradle!!! (http://discussion.visorcentral.com/vcforum/showthread.php?threadid=3874)

It works!
Idea from: http://www.ibr.cs.tu-bs.de/~harbaum/pilot/cradle.html

Modified for a Visor. Use Pin's 4 GND, 7 Vdock.

Do I need to write an article? If so, where do I send it?

You're a genius! Could you please e-mail/post the schematics? What do you have to modify on the Visor? My email address is [email protected]. Thanks in advance!

I think that here at VC would be the best place to post it!

What are the alterations necessary to the Visor? Do you still need to hook up the diode (D5) between the batteries and VDOCK (pin 7)?

My understanding of the Visor config manual was that this pin was solely for the Springboards. Does this mean your altered cradle can do that job as well now?

The alteration to the Visor is D5. After you remove the button board, looking at it button side down. On the left, is a SMT diode there, I just Silicone'd D5 on top of it, with the leads short enough to solder onto. There is enough space there to clear the case.

Then, I solder'd a jumper, from D5 to the + battery spring. The other end of D5 goes to Pin 7 of the cradle connector.

The charger ciruit is exactly as the above web page. I just put four dabs of silicone to adhere the pcb to the bottom plate of the cradle. I used header strips for the DC in and DC out connectors, just to make it easier to open the cradle in the future.

I mounted the LED's right on the pcb, because I have an ICE cradle and can see through it. For the charging led, I used a blue led to match my BVD.

The cradle gives a cool glow now.

I'm not sure what Vdock 7 is intended for, but according to Handsprings Tech Faq, if you wanted to make a Charging cradle, they suggested the Vdock Pin.

dumbuser,

If you would like to write something up for the FAQ send it to me ([email protected]) and as soon as our FAQ is back up I'll work on getting it posted. Make sure you include step-by-step instructions on modifying the Visor cradle.

------------------
James Hromadka
VisorCentral.com
Personal Website: http://www.Hromadka.com

I'm not sure that I would want to charge batteries in my visor. If something goes wrong, isn't there a risk of leaking or damage?
Is there a way though, to use this or a simpler setup to keep the cradle from draining the visor batteries on hotsyncs?

I read in another post that VDOCK might be routed in some way to Springboard modules... might this cause a problem if that's the case?

Just checking...

How's this? Questions, Comments, Pictures?

Charging Cradle for Handspring Visor

This article describes notes on making Till Harbaum's article on Palm Charger to work with a Handspring Visor.
http://www.ibr.cs.tu-bs.de/~harbaum/pilot/cradle.html

My charger applied to a Handspring Serial Cradle, using NexCell NiMH AAA cells.

I obtained most of my Parts from a local surplus electronics place. http://www.halted.com
The remaining parts were from http://www.mouser.com (They do have all the parts you need, except the
Max712CPE and the NexCell NiMH cells)

The Max712CPE was ordered from http://rocky.digikey.com/scripts/Pr...amp;M=MAX712CPE

Note: Digikey does have a $25.00 order policy which if not met, they will tack on a $5.00 Charge. Maybe a few people from http://www.visorcentral.com would like to get some orders together.


Etching the Boards.

Download the PCB artwork from Till's page.
The format was EPS, so I loaded the file into Photoshop. Remember to scale your Print Scale to the Dimensions in the Artwork.

How to Etch the board.

For those of you that need help with etching a board, I found this technique to work fairly well, if you don't have Photo Sensitized Boards.

Print your Artwork on Laser Printer Transparency.
Tape your printed results toner side towards the copper.
Place a sheet of Paper Towel over the sandwich.
Iron on your Decal on Highest Iron Setting, with No Steam.
Just apply steady pressure for about 2 Minutes.
You can lift the transparency to check for transfer and reheat if necessary.

Since I'm not a perfectionist, I went ahead and removed my decal even with some missing traces.

I went over the missing or light traces with an Extra Fine Black Sharpie Permant Maker (really not need for Etch Resistant Pens, Sharpies work Great).

Once you've fixed the thin or missing traces, throw the PCB into your etching solution. Wait. Clean.

Component Assembly on the PCB

Exactly as in Till's page. The only modifications I did was to use header strips for the Power from the Power Brick and Power to the Cradle Assembly. I did this because I wanted to mount the PCB to the Bottom Cradle plate, and it would make it easier for disassembly in the future. I also mounted the LED's right on the PCB (using Blue for the Charge Light to match my Blue Visor), since I have an ICE cradle.

DC out to the Visor:

From the Charging PCB, I took The + wire to the Visor's Vdock (Pin 7). There have been some questions regarding the use of this PIN, I just used the information from Handspring's tech FAQ for this selection.

I personally don't see it as a problem, but I'm no EE (standard Disclaimer). Also Handsprings FAQ suggested that in the Future, it may be used to charge a Module. Which I still don't see as a problem because of the way I wired my Visor.

The remaining led (-) goes to the ground pin 4.

Put 4 dabs of Silicone on the PCB and mount it to the base plate of the cradle. Close up your Cradle.

Visor Modifications:

Disassemble your Visor.
Remove the button board. Its held in place with a connector on the left (button side down, opposite the mic).

With the button side down on the board, on the left is a surface mounted diode(?). Its rectangular in shape and perfect place to mount D5 (1N4001) to clear the case. Cut the leads of D5 to about 2 to 3 CM.
Glue D5 on top of the rectangular thing.

Solder a Jumper Wire from the Cathode of the D5 to the Positive Battery Spring.

Solder a Jumper Wire from the Anode of D5 to Pin 7 of the Cradle connector.

Close up your case.
Insert you NiMH cells.
Charge.
Install your favorite NiMH charge indicator Hack
(I used the one from Till's Page)

Enjoy.

Alternative Mod for the Faint Hearted:

Alternative Visor side Mod for the faint hearted:

There were some discussions on VisorCentral http://www.visorcentral.com
about my choice of using Pin 7. Here is an alternative method:


Create a Battery pack with the AAA cells. Shrink tubing will work. Make sure you orient your cells opposite of each other like how you would normally install the cells.

Place D5 in the void between the 2 cells. Solder the Cathode of D5 to the + end of the battery pack. Make sure you're using the correct + end. The correct + terminal will be the one that is the cell closer to the Springboard Slot and on the left. As seen with the back of the Visor towards you.

From the Anode End of D5, solder a piece of jumper wire to it. About 2 to 4 inches will do, we will trim it in a bit.

Shrink tube the batter pack and install into the Visor. Remember the correct orientation.
Close up the battery compartment cover, route the Jumper wire to the outside some how. You may need to notch the cover.

Trim and solder a strip of copper sheet. You can find this at most hobby stores. The strip can be an length you want, this is just the contact area to mate to the +DC out from the cradle. My implementation was to make a strip about length of the battery compartment cover.

That's all there is to the Visor Side Mod.

On the Cradle, every thing will be the same except you will not be soldering the +DC out to PIN 7. Just take the jumper and fabricate a mating strip to the battery compartment strip. I epoxy'd the mating strip below the nub on the rest area of the cradle. Make sure you achieve contact with the strip on the Visor.

We now have an easy to remove hardware hack. Enjoy.

I have Till Harbaum's circuit working with the USB's power supply so there is no additional power supply required to power the recharging circuit. If anyone's interested let me know and I'll give you the details.


Alan

I'd love to see what you did...

------------------
MarkEagle - Ice is nice!

USB power source

Alan, I'd love to see what you've done as well.

Where can I buy the charging PC board?

I'm handy enough with a soldering iron to connect wires. I can drill holes and mount LEDs. What I can't do is make a PC (printed circuit) board.

I'd love to try adapting my Platinum's cradle into a charging cradle. We've got two visors in my house, and rechargeable batteries are the only way to go, in my opinion.

Is there anyone out there I can buy a tested charging PC board from? It would be great if it came packaged with the D5 diode, and had any wire leads already mounted on the board. A version intended for the USB cradle, and designed to use the USB power supply seems great. The big flaw, though, is that there would be no power thru the USB cable if the computer was off. I'd want my charging cradle to work overnight, when my computer is always off.

Dave

__________________
There is nothing yet made by man that cannot be improved upon.

Problems with IR Beaming

Not having seen the circuitry on this forum, I made the modifications on the following page: http://www.maksystems.com/visor/. I am now able to charge my rechargeable alkalines while they are in the case, but now my IR beam seems to be messed up. I can't recall having beamed anything before making this modification so it may have been broken from the factory, but I was wondering if any of you have had similar experiences or have an idea what would cause this.

The charging circuit I use is a lot simpler, and dumber, and it's easy to overcharge, although rechargeable alkalines don't seem to mind it that much. It's simply the USB 5V power supply, a 10ohm resistor and 2 1N914 diodes hooked up to the positive battery terminal. Any ideas why this should mess up my IR port?

The IR port can receive just fine and can send somewhat. It seems that the signal is very very faint and I have only been successful in beaming things <1 inch. Are there any hacks that might increase this power?

Thanks,
[email protected]

Caution and Warning.

Just a word of caution. I've been using the VDOCK pin myself for recharging batteries in my Visor for a year now, but receintly modified everthing to not use it now that Handspring is using it to recharge the Prism and to provide power to springboards like the Geode or cell phone. Using an external power supply for my Geode would fry my modified Visor's batteries otherwise and at only 2.7 to 3.1 v, it was not sufficient to power the Geode which expected 6v on that pin.

So if you use VDOCK, Do not user a travel charger or external power supply that connects to the Visor's port.

Instead of VDOCK, I created my own contact by looping a wire through the lower back of my Visor and alligning it to make contact with another wire similarly looped through the plastic of my cradles.

Explorer1

Hi dafiveman ,

I thinks your hack looks good and is pretty simple.
However, I think that I'm going to use NiCad batteries
simply because I have them and reduce the charging current down to 60mA (specs of the batteries manufacturer), plus I'm going to add a charging switch button on the craddle because I like having my visor on its craddle and I'm not sure the NICad batteries would appreciate being constantly in charge.

Thanks for your hack.

BobRus