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Making a cheap FTDI cable

Introduction


One of the important thing you need in Fab Academy, or when you work in Arduino, is an FTDI cable, to program and comunicate with the boards .  But the commercial FTDI cable is something you can do it yourself, and save some $/€ to spend in other proyects.
The FTDI cable is an USB TTL serial cable, named as TTL-232R. It has a 5v VCC and send and recieve capacity. You could buy in some electronic shop or through eBay, but tipically this cable cost about 20$/€.

Sparkfun: 17,95$ + shipping
BricoGeek: 17,61€ + shipping

But there are a cheaper way to get this cable, and more funny!
If you want to build your own FTDI cable from a simple Nokia USB data wire, read more.

Components needed

We can buy a CA-42 Nokia data cable from Ebay or from a local mobile phone store. In Ebay you can get this cable in about 6 or 7€ (2 or 3$ in US).

Search in Ebay "ca-42 usb nokia" and you could find some vendors selling it. Try at your languaje and domain of ebay, you could have cheaper shipping.
Also try in your local mobile phone store, and ask for this cables.

Remember: the USB part of the cable MUST have be labeled as "CA-42". 

So here are the shoping list:
  • Ca-42 Chipset cable from Nokia phone.
  • Solder and solder wire.
  • six piece of wire (best with six different colours).
  • shrinkable sleeve. (option)
  • a six 0.1" pitch headers socket.

Instructions


Here is the photo of the Nokia CA-42 Compatible USB Data Cable. The cable could come in differents colours, but the important thing is that in the USB connector has a label with the "CA-42" text on it.
Here is the cable i bought in ebay and the one selled in Amazon (15$ more expensive):

nokia cable from ebay and from amazon

The difference is the number of wires inside the cable. We only need the usb connector, which have the CA-42 pcb inside, and we want a cheap cable so....

Ok, now we need to cut the wires and open the USB closet, where there is a small pcb with a chipset. This microcontroller is covered with a rubber blub. Dosent matter, we hope that inside there are the right microcontroller.

opened usb closet and the pcb inside

In this case, here is the pads for the six cable you need to do an FTDI cable: VCC, GND, CTS, RTS, TX and RX
And here is the place of any of them in the CA-42:

ftdi cable code in ca-42

And now in the other side of the wire we need to solder the wires to the 6 pin header with this schema:

6 pin header ftdi cable positions

So now we know "what" and "where", lets start soldering. We need the USB CA-42, the 6 pin header, 6 electric wires (with different colours, if possible) and some wire thermal covers (optional).
This wire thermal covers are a piece of plastic that, in contact with heat (not fire) shrinks to fit perfectly the cable and the connector.
So here are the presentation:

components to make the ftdi cable

Now lets solder the wires to the 6 pin headers first. Peel the wires in their ends and take a solder and some solder wire. Solder each wire to the six pin header. At this time no matter which cable you use to each position, but if you had only one colour wire, maybe its better to solder a pin in the 6 header and solder this wire to the pcb, doing the wires 1 by 1.
If you have colour wires, you could follow the standard wire colours:

GND = Black
CTS = Brown
VCC = Red
TX = Orange
RX = Yellow
RTS = Green

So here are the 6 pin header solder to all the wires:

wires connected to the 6 pin header

After this, optionally, use the termal covers to cover the copper wire and the pins.

Now solder each wire to its position in the CA-42 pcb.

At the front side:

front side soldering wires ftdi

And at the back side:

ftdi wire soldering at the back side

And thats all. Now we have a nice DIY FTDI cable to use with Arduino or at the Fab Lab pcb:

finally the ftdi wire