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> My Sl-5500 Security Tool!
Da_Blitz
post Sep 1 2006, 05:53 AM
Post #16





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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 smile.gif

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 wink.gif

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)
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Drake01
post Sep 1 2006, 12:49 PM
Post #17





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QUOTE(Da_Blitz @ Sep 1 2006, 08:53 AM)
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.

QUOTE
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.

QUOTE
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 smile.gif

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

QUOTE
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 wink.gif

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?

QUOTE
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. smile.gif
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Da_Blitz
post Sep 2 2006, 05:20 AM
Post #18





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actually if you put a heatsink on the 7805 it will do more than 1A, the thing has a thermal shutdown and will turn off hen it gets to hot (VERY hard to blow up) the cooler it runs the better the regulation, so feel free to exceed the specs, there is slack alread built into them, looking at the calculations below it looks like the 7805 can do 3A if you folleow the advice bellow

if i remeber correctlly the 323 is a varible regulator, if it is the only diffrence between it and the 7805 is that the 7805 has a preset output voltage, apart form that they should be identical

i wouldnt order the parts, these are common hobbiest parts that can be bought off the shelf

bluetack is a bluish and silghtly sticky type of clay that is bought in strips and normally used to attach paper or posters to walls, dosent leave a mark when pulled off the wall and is also good at keeping water out to a certin degree

there might be a bit of confusion with the LM parts, the LM parts are made by linear devices and they do tend to name the regulators a bit diffrent even thogh they are drop in replacment parts, try finding a data sheet for a 7v-24v in regulator, 5v out and see if the naming is simmilar to the 7805

you only need a heatsink if you disipate more than 1 watt, and then its only rule of thumb, if you use a metal case then it would make sense to screw the regulator to it as you will then ground the case and be able to use it as a heatsink

the formula you need is (Vin -Vout)/current so for 7.2v in and 5v out at 3 A you get 2/3 of a watt which is within specs but i would attach it to the case just to be sure

if you are going to run USB hard drives off of it then i would recomend some 16v electrolitic capaciotrs on the output, AND in parrallel to the USB connector of each socket, this is beacuse the surge current can cause the hub to reset and capacitors will help prevent this, 10uF should be enough but the higher the better, it depends on how big the case is (if you have a mix of values put the big capacitors on Vout first, followed by the usb ports then Vin, so Vin should have the smallest (the battery should be able to handel itself)

luckily over hear the local electronics shops give you a CD with data sheets of all the parts they sell, coupled with begale (search egine simmilar to google search for linux) it makes finding data easy, not to mention i have a 1:1 image of alot of manufacturers websites on my hard drive so if you need a part i should be able to help out (its up to 15GB of PDF files now!!!)
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Legodude522
post Oct 22 2006, 03:30 PM
Post #19





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QUOTE(zacklau @ Mar 12 2006, 07:20 AM)
I moded my WCF-12, Then I builded a battery with antenna mount together. With 4 x Sanyo 2500mah Rechargable Battery. The battery life last for a long time. The main problem is the antenna is not really good. I will get a good one later.
*
Thats not how it works blink.gif It's still a 2500mah charger, just voltages are added. Not 4 x 2500. So its whatever the internal battery is plus 2500mah.

My Zaurus SL-C1000 has the 1800mah internal battery and a 2300mah[4 AA batteries] external charger.
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Da_Blitz
post Oct 24 2006, 06:51 PM
Post #20





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just found out i can get thin RC plane battery packs for about $2

7.4vx 2200maH. about 1/4 the size of my Z

its great nowing the distributor wink.gif servos are cheap as well

bieng 7.4v means i can just use a 7805 with no problems
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