Intro: Recycling a PC Internal Card Reader - Make It External & Portable
I had a bunch of these left over from some older computers that were faulty and being disposed of, so I thought I 'd make them useful again as a "portable usb device" These units are designed to be fitted inside a computers case 3.5" bay - I know you can buy something 10 times smaller for a couple of dollars online from PRC, but this exercise was 15 minutes of fun which will hopefully leave you feeling good knowing that you have saved something from the bin - for now...
Step 1: Pry Open the Unit!
Using a flat screwdriver pry open the four metal tabs that hold the lid closed
Once open you can see it has a short length of cable fitted with a standard USB header plug.
Fortunately the color coding for the power and data lines on this cable were standardised making the adaption to a USB cable easy! - this will become obvious later once you cut up the new "donar" cable.
Phillips head screw driver
Flat blade screwdriver
A "donar" USB cable with "A" type pug on one end
A small cable tie to secure the new USB cable
Step 2: Preparing the Board & Removing the Existing Wiring
Remove the board from its chassis - two Phillips head screws
Make note of the colours and which pins / area of the PCB where they are routed to before removing the original header pins and cable.
I used my cutters to help with the removal of the header pins, these could be left and you could solder the new cable directly to these but I went for a "direct" connection to the board option - see photo in next step..
Once you have chopped the headers off square to the board, gently heat up each solder pad on the PCB and gently tap the board on the bench to dislodge the excess pin.
Step 3: Preparing the New USB Cable
Once you have sourced a suitable USB cable - in my case an old 1 metre extension "A" Cable, Cut the female / socket end off and strip back a least 30mm of the outer insulation to allow you to work with each conductor with ease.
Strip and twist the strands of each individual connector colour together with your fingers.
Then using a soldering iron "tin" each conductor (5 in total) individually ready for insertion into the PCB
Red - (+5v)
White - (data -)
Green - (data +)
Black - (Ground)
Shield - (cable shield - connect to ground)
Step 4: Attaching the New USB Cable
Push each wire through the solder pad holes of the PCB (note: when working on the underside of the board the colour code first noted will be in reverse order)
Solder each wire in place onto the pads
The shield wire can be connected to the chassis or a spare ground pad on the PCB
Using a cable tie secure the cable to the chassis to prevent the cable and connections from being pulled from the Printed Circuit Board.
Step 5: Check Your Work and Re- Assemble
Before attempting to plug into your computer ensure that you have not created any solder bridges across pads on the PCB.
Check that your wiring follows the same "code" as the original header cable and that all screws and wiring are well secured.
when i plugged my unit into a PC running Windows 7 it took a bout 30-60 secs to install a driver and I was away!