IDE harddrive cables

There is a neat way to connect arduino to your breadboard and avoid all those crazy and loose jumper wires: the phi-connect shield.

The phi-connect stackable version can be stacked below shields so you can benefit from both shield functions and a large breadboard and easy to switch projects in and out.

As you can see from the top to bottom is an arduino shield (phi-2 shield), phi-connect shield that passes all arduino connections to the breadboard via an IDE hard drive cable, and the arduino.

Now you know how useful an old IDE hard drive cable can be. But hold on before you star using just any IDE hard drive cable yet, because you need to get the right cable or otherwise puff, short circuits!

Here is why: newer IDE cables (aka 40-connection 80-wire ribbon cables) are made so that many of the connections are all connected together to ground. So if you’re not careful, you will short your circuit or at least ground some signals and make your project malfunction. So what kind of IDE cable should you use? 40-connection 40-wire cable. Make sure you could 40 wires on the ribbon. You can also use old floppy drive cables, which are 34 wires, so less connections.

Here is a comparison of 40-wire (left, often having 28AWG marked on it) and 80-wire (right, often having 30AWG marked on it) IDE cables, make sure use the 40-wire!!!

You can connect to an LCD easily with such a ribbon cable to arduino.

(If you look closely I actually used an 80-wire cable, which made my life much harder. Don’t do it!)

Here is the wiki page on this topic:

http://en.wikipedia.org/wiki/Parallel_ATA

Painful details if you want to know, why I don’t recommend 80-wire IDE cables:

OK, that “identical” look between the two versions (40-wire and 80-wire) could fool you and certainly did me about a year ago but after some serious problems with my very first try on an LCD I pulled out my multimeter and measured. Those pins “2,19,22,24,26,30, and 40” to are indeed all tied together, plus two pins are N/C too! The newer 80 wire ribbon cables are older 40 ribbon cables are 30AWG (thin wires) and 28AWG (thicker wires). A closer look will be enough to tell, although only if someone has one type at hand then they’ll have to read (hint: keyword 30AWG on cable) or count (hint:superfine permanent marker comes handy).

The media are no different, plain cables. But the connectors are very different if you pry them open. The oldie 40-wire version has two rows of sharp cutters ( I don’t have a name for the part that cuts through insulation and makes metal-to-metal contact). Top row is odd pins and bottom row is even pins (or the other way around if you hold protrusions on the connector downward. All those are individually connected to their female pins. If you open a connector on a newer 80-wire version, there are three rows of sharp cutters. Besides the top row (odd pins) and bottom row (even pins), the middle row is all interconnected one piece of metal. It cuts every other wires, plus those positions corresponding to pins 2,19,22,24,26,30, and 40 on the female connector. The “41-80” wires are meant to be every other wire on the ribbon cable and are also grounded for higher speed communication. They don’t make to the connector’s other side, only the first 40 do (minus 1 behind a mechanical key).

When I was designing my phi-connect shield for prototyping breadboard, I studied these two types of cables over and over with online materials and checked every ground pin with my multimeter and I decided to go with 40-wire cables for simplicity. Thicker wires and simple connection scheme against benefit of every other wire being grounded but complex connection scheme I made my choice. I think I did my homework.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: