My Sl-5500 Security Tool! Options

[zacklau]

Here is my mod of my zaurus! It has a external antenna plug and extra 10000mAh battery for long lasting.
Here is some pics.

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[Da_Blitz]

all you need is a 3 pin regulator, one pin is Vin one is gnd and the other is Vout

a low drop out regulator provides regulation at voltages above Vin -Vout => 0.2 the 7805 you need about a 1v diffrence, so if its a 5v vout then you get regulation down to 5.2v then it cuts out and you will get 5.2v going into your device

the erason i mention that is that some Z's are picky about thier input voltage and will blow the charging circutry if you give it more than 5.1v

the best solution is to just add another cell to your pack and get a 7805 from any electroncis supplier in your local town (they are as common as transistors/resistors) and also grab 2x 10uF electrolitic capacitors

if you do follow my advice then the middle leg is gnd, if the tab is facing away from you then the 7.2v comes in the left pin and out the right, all you have to do is put a capacitor in parrelel to the right and middle pins, and the left and middle pins. if you arent sure which way they go in (electrolitics only go in one way unless you like big bangs and cleaning up fluff for an hour) or even ask them to draw you a diagram

also keep in mind that at 7.2v and with wires less than 5cm on Vin and Vout you dont actually need the capacitors as the battery has very little noise in the line and the load is fairly constant (the capacitors help to even out the flucutaitons and provide power when there is a huge spike, which you wont have), if you dont belive me check the data sheet

you dont even need beradboard if you just have insulated wires.

good forms of insulation i have persanally used in a live PC:
heat shrink (the best)
stickytape (good in a pinch)
bluetack: the most handy discovery i ever made

Z current draw is 1A max, it can go higher but you wont domadge your Z if you cant provide enogh, the 7805 is ratted at 1A and will go higher in most cases (you can make it do 25A if you read the data sheet

avoid the 78L05 which looks like a small black cylinder, its ratted at only 100ma's the 7805 has a huge metal tab at the back, in fact right down 7805 because the 7905 will give you -5v and WILL fry your Z (a mistake you do not want to make)

well i hope that is all you need to get satrted, a bit more than you needed but at least you are aware of the issues. if you have any problems then just post back, PM me or if you live in australia near sydney i am willing to make one up for you (i have tha parts here to build about 20)

[Drake01]

all you need is a 3 pin regulator, one pin is Vin one is gnd and the other is Vout

a low drop out regulator provides regulation at voltages above Vin -Vout => 0.2 the 7805 you need about a 1v diffrence, so if its a 5v vout then you get regulation down to 5.2v then it cuts out and you will get 5.2v going into your device

Judging by the specs I've seen on most of these, I think I'm going to go with a 7.5V - 9V pack. The LDO regulators I've seen don't have a high current capacity, with one odd exception I found on the Maxim site.

the erason i mention that is that some Z's are picky about thier input voltage and will blow the charging circutry if you give it more than 5.1v

+/-0.1V?!? You've got to be kidding! Most of the specs I've seen are +/-0.2V, although I'm assuming these are limits and the unit generally provides something more accurate. Yikes.

you dont even need beradboard if you just have insulated wires.

good forms of insulation i have persanally used in a live PC:
heat shrink (the best)
stickytape (good in a pinch)
bluetack: the most handy discovery i ever made

What's this bluetack stuff? Never heard of it.

Z current draw is 1A max, it can go higher but you wont domadge your Z if you cant provide enogh, the 7805 is ratted at 1A and will go higher in most cases (you can make it do 25A if you read the data sheet

I found a catalog from BGMicro lying around. I checked out specs on a couple of the regulators they carry and the LM323 looks interesting. It will provide up to 3A. I'm looking for something that can handle more than the Z needs because I'm planning to put this all together into a little USB docking station. I'd like to provide enough power to comfortably run the Z plus at least a keyboard and mouse, but I may end up connecting something else, too.

BTW, how much heat do you think something like this would dissipate? Would a heatsink be advisable?

well i hope that is all you need to get satrted, a bit more than you needed but at least you are aware of the issues. if you have any problems then just post back, PM me or if you live in australia near sydney i am willing to make one up for you (i have tha parts here to build about 20)

Thanks for the help and the offer. I think I'm on the right track. I've got a proto board (or whatever you call the breadboard-like thing for mocking up temporary circuits) and plan to test the circuit before soldering and hooking it to my Z. If I run into a problem I might pester you again.