Arduino Uno

The Arduino folks have announced a new board, the Arduino Uno. I’ve worked with the Arduino Duemilanove, the board it’s replacing in the past and found it to be a great starting point for a project. In fact I still have another Duemilanove sitting around ready to go for the next crazy idea I have. The upcoming Arduino Ethernet also looks very interesting, if not more interesting.

No announcements on pricing just yet. Very cool stuff for hardware hackers.

Update [9/26/2010 @ 10:50 PM EDT]: Looks like the going price is $29.95$30, about $5 more than the Duemilanove.


Building A PC Headset Adapter For IP Phones

Building a PC headset adapter for a Nortel 1120E actually turned out to be dead simple. The headset port is actually a pretty standard 4P4C port (also known as RJ9 or RJ10 apparently). For about $5 I was able to put together a fully working adapter to use any standard PC headset.

I suspect this will work just fine with most phones even non-IP phones however your mileage may vary. Obviously this is at your own risk.


If you have an cable from a phone receiver you could easily reuse that, just cut one end. Those are just 4P4C cables.

The stereo connection jacks are rated 5,000 cycles, though they feel a little flimsy to me. For the price however they or not bad, just proceed with caution. If you build this and intend to plug/unplug often you may want to consider another one. For me, if they break I’ll swap them out.

I was originally going to solder and tape it up to save space rather than use a board. The board was for prototyping and I’d just reuse it for something else later. At least for now however I’ll just leave it all taped to the board, it seems pretty stable if you leave the headset plugged in. I just taped it to the base of my monitor. I really wanted a breadboard, but there were surprisingly none in stock at RadioShack. No breadboards at RadioShack is like a McDonald’s without burgers. The PC board however worked for the task.


To summarize how it’s connected, a 4P4C cable has two conductors for speaker and two for microphone. It’s simply a matter of connecting them to the correlating jack with the correct polarity and you’re done. The following diagram (from Wikipedia) illustrates the pinning:
4P4C Pinning

On the SJ1-3523NG jacks, this corresponds as follows:

Audio out:
  Pin | Wire
    3 | Green
    2 | Red
Audio in:
  Pin | Wire
    1 | Black
    3 | Yellow

A little testing showed that the presence of a microphone is how the Nortel 1120E can tell if the port is connected or not. That means you can’t just use the headphone for example to listen in on a call. A microphone must be connected (muting works fine however).

Final Product

I grabbed a Logitech ClearChat Style Headset which retails for under $20. Works perfect for the task and has inline controls for easy mute/volume control.

As a result I put this together using only a few dollars of parts and using only tools found in my cube (wire strippers, wire cutters, scissors).

There you have it. It only costs a few dollars and is dead simple to wire. Now I can code while on calls without having to decide between speakerphone, which echos when several of us are on the same call or risk neck pain trying to balance a phone receiver.

IP Phone Headset Adapter

In practice, I have tape holding the jacks to the board. I removed it for the photo shoot to better show how the wiring is done.


Standardizing Labels for Electronics

Gizmodo wants electronics to have standardized labeling to make things easier to compare. I suggested something along these lines back in 2008 about energy efficiency. Their proposal is a little more broad though I like it.

Recently I tried to get stats on power consumption for a product from a decent sized manufacturer. Interestingly their sales and support team didn’t know how much power it consumed. They didn’t even know where to get such information and suggested they could try contacting engineering but weren’t sure if it was available. Something as basic as “how much electricity does your device use?” is not available online or upon request.

So yes, I’m 100% on board with this proposal. It’s insanity that it’s so difficult to find anything more than some silly marketing specs (3D, HD, WiFi, “Fast”). It should be listed on the product details page on any online store, or on the back of the physical packaging.

It’s easy to get all sorts of stats on components when purchased individually (RoHS, Lead free, 80+ certification, power consumption, thermal specs), but buy a device full of components and it’s a mystery in many cases regarding the real specs.

Considering how much we use our gadgets, knowing such information can mean big savings. Think about your home router and switches. Just a little power savings can add up over the 3-5 years you have them installed (and running 24×7). If you live in an area where power is expensive it may make sense to actually spend more for a higher efficiency device.


Cable Fail

I’ve been looking for a 4 conductor male TRS connector (Apple iPhone headset jack) for a small project. Simple enough. I found a cheap extension on Amazon a week ago that seemed to fit the bill. For posterity here’s what the description says:

Technical Details

  • Made and designed to work seamlessly with the Apple iPhone.
  • Will act as an extension cable, carrying both the stereo audio and microphone signals from your device.
  • Allows the adapter to be used with stereo headphones that also have integrated microphone functionality
  • Made with Nickel plated materials, 3.5mm 4-pole plug, 3.5mm 4-pole jack and a 10 cm (L)
  • A perfect accessory for your NEW Apple iPhone.

Emphasis mine.

It arrived in an envelope containing a tiny ziplock back with no labeling (it’s barebones). When I hooked it up it seemed that audio quality wasn’t very good. I never bothered to check out the microphone. At that price it obviously didn’t make fiscal sense to return it as the postage costs about as much as it’s worth. So I decided to finish dissecting it.

From what I can tell it’s actually 3 wires. Each is a different color (red, copper, green) with some white strands in the core. The female jack has two prongs with one wire attached to each and the enclosure itself which seems like it’s the ground. My suspicion is that the audio is either combined or only one channel is used making it actually mono. The jacket I dissected was molded on so it was virtually impossible to remove the plastic without severing the thin wires in the process.

Here’s what the wire and the female jack (sideways on the bottom) look like:
Full Sized iPhone Wire Dissected

Here’s the jack from the back side. I suck at photography and only have a P&S camera, so it’s a bit blurry:
iPhone Cable Female Terminal

I’m now debating trying another vendor or a more expensive 2.5 mm to 3.5 mm adapter.

My original plan was to find a new 4 conductor TRS male plug, but that proved impossible via the usual sources. 3 conductor is easy.

If anyone has suggestions feel free to reach out.

Apple Hardware Software

MacBook Pro Sleeps When Lid Closes

The MacBook Pro still has a quirk that has always bothered me. It’s not a hardware issue, it’s a software issue. Power users with laptops know about “closed clamshell” or “closed display” mode. That’s when you use a laptop with a desktop keyboard and mouse and the laptop remains closed. I don’t think any OS I’ve used totally gets this totally right, they all have their quirks. The MacBook Pro just has this one quirk that gets to me.

The problem with the MacBook Pro is when you have the computer open and on and you connect another display you’re given the option to mirror or use the display as a second display. If you mirror and close the laptop it goes to sleep. That’s completely illogical. There seems to be no way to disable going to sleep in this situation that I can find. I can’t imagine why anyone would want another behavior when closing a laptop while having a display and input device connected. When no display is connected and the laptop is closed, it should obviously sleep.

Searching on Google returns numerous forum threads with people who also have this gripe. Even a check box in the Energy Saver pref panel to facilitate this would do nicely.

For the record Windows is no saint either. It’s handling of monitor resolutions, especially if your desktop display is a different resolution is abhorrent. It can result in anything from reshuffling icons to putting windows out of the display area. I’ve never even bothered with such functionality in Linux, at least not yet so I can’t speak to its competency in this area.

Apple Hardware

Apple’s Liquidmetal

Apple has gained an exclusive license to Liquidmetal for consumer electronics. Liquidmetal Technologies will still be able to sell to other sectors, just not consumer electronics according to The Baltimore Sun.

The technology itself is pretty interesting. I have a SanDisk Cruzer Titanium I purchased back in 2006. Despite being used pretty much every day and being thrown around constantly, it’s 100% intact with a few very superficial blemishes on its finish. It’s extremely durable, small and light. I’m sure they’ve had advancements since then that are even better.

I suspect this is not the end of the Aluminum era for Apple products. I think the Liquidmetal licensing will be used mainly for the iPod, iPhone, iPad lineup. Perhaps it will extend as far as the MacBook Air. That’s where Apple is really in need of stronger lighter materials. I suspect the cost of Liquid Metal for a 15-17″ MacBook Pro just wouldn’t make sense. Same goes for the Mac Pro.

Apple Hardware

Apple Device Charging

After my recent adventures in the world of USB power I found this article on Apple USB device charging especially interesting. It’s a shame Apple is always playing a cat-and-mouse game with hardware design.

Hardware Software

Email Alarm System

I’ve been in the mood for some hardware hacking for a while. Recently at work I thought it would be nice to have a way to know if an important (emergency) email came in that required attention. These fire-drills are just part of the job. I have multiple computers and screens so an on-screen alert isn’t always effective. Audible alerts don’t work either because speakers are only connected to one computer at a time and often headphones are plugged in. I need something more independent.

My solution was to build a USB alarm system: Two rotating LED lights to get attention visually as well as a 76 db piezo buzzer which chirps when the system is activates to help get attention. The buzzer only chirps and only when the system first invokes so it’s not an annoyance. It’s enough to get attention, but not enough to bother others. It has multiple chirps so that I can potentially setup multiple alert types.

Now we can really be on the ball!
P1 Bug Report Alarm
Obligatory goofy office signage

Apple Hardware

iPhone 4 Teardown Analysis

iPhone 4 Teardown

iFixIt has their traditional teardown posted. After analyzing every picture, a few things are noteworthy:

Stainless Steel Antenna

The stainless steel antenna strikes me as more than just an antenna, but Apple will never admit it. The iPhones before all suffered from the same structural weakness. If dropped so that it lands on a corner or a side, the body flexed putting pressure on the glass and possibly digitizer if the impact was strong enough. This resulted in the shattered glass you sometimes see people walking around with. If the phones land on their backs or faces, they are often fine minus a tiny scratch or two. This is because the sides of earlier models were not very strong. The metal band you see on the earlier models isn’t enough to hold up to the force of a drop from 5 feet. It was a thin piece of stainless steel around what is otherwise plastic. Most of the metal in the previous phones are actually thin EMF shields, not anything structural.

I suspect this new frame also serves to strengthen the phone and prevent this type of damage.

Creative EMF Shielding

The previous iPhones pretty much just had a large EMF shield like we see in most consumer appliances. The new iPhone has a bunch of tiny EMF shields. The advantage to this approach is that they can cram more things into small nooks and crannies. Apple is clearly desperate for every nanometer of space they can get.

No Surprise Chips

Nothing inside circuitry wise is even remotely surprising. Samsung flash memory, Broadcom WiFi, Bluetooth (BCM4329), Cirrus Logic audio codec, TriQuint/Skyworks GSM/GPRS chipset, STMicro accelerometer. The new gyroscope is suspected to be STMicro, which isn’t shocking. There is a Broadcom GPS (BCM4750) chip, same as the iPad. Prior to the iPad, the iPhone 3G and 3GS used an Infineon Hammerhead GPS chip which was questionable in performance. Perhaps this will finally give the performance necessary for eventually making turn by turn directions a reality.

Battery Technology Needs To Improve

It’s becoming clear looking at the iPhone 4 that Apple made the right decision to make the battery non-removable. The hardware and extra material to make it removable would have really bulked up the phone. At this point the battery is by far the biggest single space consumer in the iPhone. Look how dense the circuitry for the phone is in comparison to the hulk sized battery. Apple crammed what a few years ago was a full PC into that sliver on the side of the phone. The rest is largely the battery with glass and LCD in front and various speakers, microphones, cameras and sensors mixed in the otherwise empty nooks.

Apple really needs to find a technology that can offer a higher power density ratio for the iPhone to get any lighter or longer battery life. Custom silicon will help them, but it’s only going to go so far and so fast. It’s becoming obvious that power is a major concern and limitation for Apple engineers. I suspect Apple spends a ton of R&D time and money trying to figure out how to deal with this limitation the best they can from the physical space requirements to power efficiency and software innovations.

Don’t be shocked if Apple either invests or just acquires a company who is doing something interesting in the battery space just like they picked up P.A Semi.

Environmental Stats

Apple hasn’t published their environmental report yet on the iPhone 4. I’m curious how the greenhouse gas emissions changed between the iPhone 3GS and iPhone 4. Several things have changed about its composition including the glass and steel frame that should make it interesting. The iPad’s slightly different (and larger) power adapter boasts an 80% efficiency rating. The iPhone 3GS is only in the 70% range. I’m curious if Apple quietly updated the adapter at all or not (I suspect not, but it’s possible).

Image courtesy iFixIt


Bad Capacitors

A few weeks ago, one of my work PC’s decided to just died on me. It was able to reboot but crashed late in the boot process. Eventually it turned out that one of the video cards (NVIDIA Geforce4 MX4000) went bad. Pulled the card and I just threw it on a shelf. The other day I looked at it and noticed 4 of the 5 capacitors on it actually vented. I took a few quick pictures of the carnage. You’ll likely want to go to the real high resolution pics to see the detail.

The alarming thing about this is that capacitors are found in a very widespread range of products. That’s why backups are important when you have critical systems.