Crystal from glare-reducing?

I have been using the screen protectors from my old PDA, a set of WriteRight screen protectors. I think they're vinyl. Anyway, I recently used my multi-tip pen to fill out my timesheet form and forgot to retract and extrude the stulus tip, so I got a little line of black ink across my screen. No problem, just apply a pencil-eraser, and it goes away. But, lo and behold, not only did the ink disappear, but so did the cloudiness that comes with the screen protector. Since I had already started, I applied the pencil eraser to the remainder of the screen, and now I am using my PDA in all its high-contrast, colorful glory! Naturally, the glare-reducing properties were removed, and reflections show up with almost mirror-like clarity, but I now know that I can convert the remainder of my old protectors (after cutting them down and applying them) to my Ax.
The pencil I used was a wooden pencil:
USA Paper Mate American HB 2
note, use the eraser, not the pencil. I tried other erasers, but one of them was scratchy and another was ineffective. It's up to you to experiment and determine what will work with you. And yes, that tiny bit of fiber under the protector is still there.

Disclaimer: No, I don't know if this will work with your screen protectors. And no, I don't owe you a new PDA if you destroy your screen or digitizer. As a matter of fact, I remain un-culpable if you are distracted by its beauty and drive off of a cliff.

       

Parts:

• The case came from a laser/pen/stylus that I bought at RadioShack.
• Charging socket from RadioShack. $2.59 for a 2-pack. I had it on hand already.
• 7805 +5VDC regulator was from RadioShack: $1.69
• Plug from RadioShack, was taken from my USB hub/charger adaptation. $2.59 for a 2-pack.
• 6-AA battery holder from jameco grab bag. :-)
• Batteries from Target. Ray-O-Vac 2500mAH-AA, $8.99 for a 4-pack. No sales tax, hurricane tax holiday! Extended cost for 6 batteries = $13.50.

Total cost: $17.78. Or you could consider it $20.00 for the parts that came from supply.

Materials:

• Wires and Silver-Tin solder on-hand.
• Rubber grommet. From on-hand, came in a pack of 50 or so, individual cost quite low.
• Nuts and bolts from on-hand.
• Heat transfer compound.

Tools:

• Solder gun.
• Nibbling tool.
• Drill with bits.
• File or wire brush.
• Screwdrivers.
• Safety Goggles.
• Gloves.

Safety:
Wear goggles to protect your eyes from splashes of molten solder and stray bits during drilling/deburring.
Wear gloves to protect from sharp metal bits during drilling/deburring.

Schematic



Procedure:

• Prepare the case. Drill holes for:
  - Retainer screws for battery pack
  - Mounting screw for regulator.
  - Charging port. Use nibbling tool for square end.
  - Cable. I slotted this one; just slip the grommet in with the top off.
• Test-fit battery holder, measure and cut wires.
• Solder connections according to schematic.
  - Be sure to fit the grommet and tie the wires in a knot (prevents cable from coming out) prior to soldering output cable.
  - Solder wires to the charging socket and output plug (wires + plug = cable) before attaching them to the regulator.
  - Attach battery terminals to regulator leads.
  - Now attach input (socket) and output (plug) wires to regulator leads.
• Install battery holder.
• Apply heat transfer compound and install regulator.
• Install charging socket.
• Install grommet.
• Install fully-charged batteries.

Results:

Assembled, but without socket and grommet holes:


Top off, socket and grommet installed:



Top on, fully assembled:



Detail of the output (grommet and cable) and input (socket) ports:



Close-up of the socket. Note the hole is a little bit jagged: I need a little practice with the nibbling tool!



It's not just for charging your Axim.
Shown here, it is running my Asus WL-HDD and I'm playing Monty Python, the Ministry of Silly Walks on my X50.

       

I have been using the innopocket magnesium case and love it very strong I have no problem with putting my Ax in my back pocket and the case is padded no problemd with damaging my Ax

Updated post #32, above (details of making extended charger). Added more pictures.

An (X) in my post denotes a wireless post from my Axim.
A (T) in my post indicates a wireless post from my ipod Touch.

I am nerdier than 100% of all people.
Are you a nerd? Click here to find out!

       

PocketBrain, the regulated powerpack looks like a great idea!

Can you tell me why it's much better than a regular 4xAA battery extender? (of which I have).

I'm guessing that:

- the regulated 5v DC helps the Ax behave much better. In that the NiMh cells will push out 5v DC straight without fluctuation? I've no idea on what i'm talking about. I'm not an EE.

- You can use more than the usual 4xAA NiMh of which I noticed you used 6. So, wired in parallel (or it series?) you'll get 2500mAh at a voltage of ~ 7.2V but regulated to 5V. As the mAh rating drops so does the V i'm guessing but it will be still useable for a longer period of time compared to an unregulated battery extender?

I've noticed that using my 4xAA battery extender (bought from pc-mobile.com) really needs quality NiMh cells.

When i've used lower quality NiMh cells i've noticed that the extender will power and charge the Axim x51v as long as you have at least 75% left ... maybe as low as 60% if i'm using freshly charged NiMh quality cells (I need to do more testing).

I've also noticed the strange phenomenon in that my cells were low and it ended doing some strange reverse charging thing with my Ax. When I checked the Axim later on I found the battery almost totally dead which alarmed me. I'm still not sure of the EE background of this situation. All I know is that if I want to charge my Ax I better have fresh charged cells ready to go.

answers in bold.
Note that the regulator has an overhead of approximately 1.6V, meaning that it has to have an input of 6.6V or so to output 5.0V.
A "buck" switching regulator will boost the efficiency considerably, and the loss of energy as heat will be cut. If I use a "boost" regulator on it, as well, then the batteries can discharge almost completely before becoming useless. The regulator itself can also reduce the "back-charging" effect, wherein the battery pack is a load to your internal battery. Also note that a more-deeply discharged pack will show more sensitivity to load current, so the practical range of voltage per cell will likely be lower.

       

Thanks for the informative answer PocketBrain. I've been edified.

One question that wasn't touched upon was the situation where the OEM Dell battery being drained excessively fast when hooked up to a battery extender.

I think the answer to this was in that massive sticky in one of the forums ... but it went something like this:

when the voltage of the battery extender drops to a certain threshold (i'm guessing less than the OEM Dell internal voltage?) then the Dell battery may actually begin reverse charging the extender so that the Dell battery will drain like mad.

That's why people will report that they turn on their Axim and have "0" battery charge left after thinking that it should be 100% after being hooked up to an extender. That actually happened to me once.

Is this correct? Or something like that?

Thanks PB.

Yeah, something like that. I really don't have the schematics for the charging/protection circuit inside the Axim. It may not be charging the extender so much as just self-discharging with the external underpowered battery in place. Switching on/off of the charging circuit may be simply drawing enough current to discharge the internal battery.
Using a voltmeter, the charging input shows up as ~0V, so that tells me it should apear as open, so the power shouldn't be going into the external battery; it should have protection against that.

So, the discharge you see when the underpowered external pack is connected is probably the internal battery powering the charging circuit as it cycles. My best guess, according to the evidence at hand.

Note: I corrected overhead voltage in my response, it's actually about 1.6V. All the more reason to build a switching regulator, the power loss in the switching transistor would be a forward-biased transistor, less than a volt, and it would only be on part of the time, which would cut your overhead by a proportional degree.

       

Cheapskate screen protector!
Get a sheet of 8 gauge plastic (used as tablecloth protectors) at JoAnn fabrics or another fabrics/crafts store, cut it to fit, apply. $2.50 for 1 yard x 4 feet or so. You could make over a hundred for a unit cost of under a nickel.

An (X) in my post denotes a wireless post from my Axim.
A (T) in my post indicates a wireless post from my ipod Touch.

I am nerdier than 100% of all people.
Are you a nerd? Click here to find out!

       

You can connect via WiFi only in a WiFi hotspot. If you have a bluetooth cell phone, then you can connect anywhere in your cell network. Try Ikehiker's WiFi guide at: http://wifi.aximsite.com .
Check out the official GPRS settings thread (cell network) at: http://www.aximsite.com/boards/showthread.php?t=82337
Also check out Gigi's "What can I do with my Axim?" tutorial: http://www.aximsite.com/whatcanidowithmyaxim/

As far as the satellite connection goes, that's way out of my area of expertise. Only think I can think of is you would need like a DirectDuo link and a WiFi router connected to that. It would be bulky and expensive. So, if you are going to be using your Axim from Antartica, you might want to invest in a larger memory card if you want to access your entire music collection.

(X)
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An (X) in my post denotes a wireless post from my Axim.
A (T) in my post indicates a wireless post from my ipod Touch.

I am nerdier than 100% of all people.
Are you a nerd? Click here to find out!

       

Not Axim-related per se, but used to show how you can take an external controller and mate it to another circuit board to wind up with something new.

I used the guts from a $4 PlayStation controller and connected it to the buttons in a C&L Championship Joystick for SNES.

First picture, the stick itself. Note the mismatched color of the cable.


Second picture is the functional interior of the stick. You can see the button and stick switches, and the wires going to the old PS controller board. I just soldered the wires to the button contacts. Simple.


Third picture: close-up of the PS controller board. Ugly, but beautiful at the same time.


Fourth picture, the old and disused SNES board and cable. I have the hacked-up IDE cable standing by to connect to the old control board.


You can apply this lesson, and I have had a plan to for some time, to a controller for the Axim. Get your hands on a Belkin Snap-N-Type keyboard and mate an old SNES or PS controller (digital, I wouldn't fool with the analog for now) and you have a docking game controller.


So, what do ya think?



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New ripboard landscape layout:
http://www.aximsite.com/boards/showp...7&postcount=13

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Sure is pretty, huh?

       

WOW.. These are some excellent tips! Thanks PocketBrain!!

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Alright, a new version... It's not perfect, I'm having a tough time making the * and + keys show up without shift involved, so it looks a little bit odd. More gnireenigne to do.


Also, note that you can actually read the blue keys on the PDA itself. My snapshot tool comes out with the colors a little skewed.

Attached Files

Mod_Landscape_ripboard.zip (2.5 KB, 44 views)