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:

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.

Desoldering tricks

Sometimes you need to remove parts from a soldered board. How?

Here is my trick of the trade:

1) Buy some radioshack desoldering wick, suck out the solder from a part. If you can’t remove all solder, take your small screw driver, drive its tip of driver into the wick to make a small puncture hole. Then press the hole against a pin to be desoldered. This makes the wick surround the pin, maximizing area of contact, instead of staying above it or on its side. Then heat the wick around the hole and you will get most of the solder out. I’ve done this quite some times and each time it worked nicely. Next, if you feel you’ve removed all the solder from a pin but it won’t budge, just slightly rock/push it a bit with a flat-head screw driver so the last bit of solder is broken.

Desoldering wick/braid

Desoldering wick trick to remove solder from a pin

2) Some people also opt to destroy the plastic holding the pins together before they proceed to desolder each pin, divide and conquer.

3) You may also buy a radioshack desoldering iron to remove solder by larger amount. I found the desoldering iron very useful at times but as it ages somehow it is unable to remove solder cleanly as before.

Desoldering iron

4) You could also use solder sucker or desoldering tool but I never got hold of a good unit so I can’t say too much but a good one may work nicely.

Desoldering pump/tool

Desoldering bulb



5) If you have a higher-power (de)soldering iron like 30W or more, keep the part in your third hand, try to desolder and when solder melts, quickly use a pair of pliers to pull out the hot pin. This sometimes seals the pin hole so make sure you remove as much solder as you can with some method.

What is this?

Thanks to arduino forum and warm-hearted friends near and far, I have had another great success trading my shields for computer-related stuff. I got tons of old games from a local friend. Now I have DOOM! DOOM-2 and my disappointing purchase of DOOM-3 🙂 Another friend sent old CPUs all the way from France! I even got this one from a friend in CA:

What is it? I know the answer, do you? 😉

By the way, I am now open to trade all my shields for computer stuff, mostly cpus since I don’t have much space at home, also classic computer games (original, preferred on floppies). Drop me a message!

Announcing phi-2 shield with 20X4 display!

As some of you have waited a while for this. Now it is here, everything about famous phi-2 shield but bigger on the display estate. Instead of a 16*2 character display, it boasts a 20*4 display. It fully takes advantage of the Text-based User Interface software library phi_prompt, which I updated with tons of features for you to use.

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Here is a video of alarm clock version 4:

It is now available at

Project code updates

Since I have updated my phi_prompt library, some of my project codes stopped working due to the library update. I’ve made changes to some of them to get them up to date and still have to update several more. So I decided to make a chart to show how my various libraries are related so that if I update one library, what else I need to update in order to make all my codes work.

Here is the chart. It’s too big to fit in the blog so feel free to click on it to show the whole image.

This also shows some planned updates such as adding functions in the I/O layer to make the user interface access more types of switches such as keypads with column/row pins, IR remote keys on an IR remote, PS2 keyboard, etc, and also in the system layer such as porting the phi_prompt library to graphic lcds (must be lots of work). Also the library versions are included so that you can check your folders to make sure the correct versions are there to support your applications.

Thank you!

Thank you all for visiting my blog! I hit a new high the past month at 5,706 visits per month. I’ll do my best so you will come back for more new posts this summer.