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.

Attached File(s)

 DSC00206.JPG ( 297.19K ) Number of downloads: 539
 DSC00208.JPG ( 418.73K ) Number of downloads: 490

 

[Da_Blitz]

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!!!)