Finally, I received the new PCBs from the manufacturer, after the first batch were found to be defective on track continuity (possibly due to too aggressive etching). This is a short video showing how the first one I assembled and programmed works:

If you want to meet up, I will be at the Mobile World Congress today, and probably on Thursday & Friday too. You can ping me on Twitter or leave a comment. I’ll be bringing my new business card along, I guarantee you won’t get another one like it from anyone at the Congress! This is a preview, I’ll be posting the story and design behind it in a couple of days:

Just today UPS dropped off (well, I intercepted the driver in mid-flight, but that’s a different story) the Jawbone Bluetooth headset I was waiting for – and boy, does it work wonders! This has to be the best implemented piece of DSP technology I have seen. If you don’t believe in ‘official’ demos and blurb from jawbone.com (they are true), just check out this audio recording [WAV, 48kHz, 1.7MB]. The first part is recorder using my Mac with an unsquelched radio about 30cm from the headset, with the DSP turned off. I then turn it on, and the audio is recorded perfectly, with barely a hint of the background noise.

How do they do it? I’ve not opened this baby up, as it’s too good-looking (and expensive), but it seems that they combine two directional microphones with a vibration sensor (the small white dot you see on the picture) that picks up bone-transmitted voice from your jaw (thus the name). By matching the vibrations, which are not enough to actually record sound, with the incoming audio from the microphones, they can take away the extra noise very effectively. I should know, as in my previous job, one of our biggest problems was noise and echo cancellation (I was responsible for electronics R&D at SouthWing, designing and testing Bluetooth headsets and other accesories) – and we could never completely kill feedback echo, and noise – forget it. Our designs were in the top league as far as audio quality and noise went, but try what I just did today and the whole recording would have been like the first half.

Good job, Aliph!

You probably have seen the video on YouTube about a molten Fonera, apparently due to overheating, which shows the plastic case completely deformed. Gizmodo (also in spanish) and other sites are also reporting on this. As usual, Fon has censored the post on their forums that broke the story, but alas, thanks to their partners at Google, here is a cached version. Even Martin Varsavsky seems worried about this. It seems the damage is obviously from heat, but could it have come from the Fonera itself?

I, and others, have our doubts about wether this video is a fake stunt, or a true story. It is true that the Fonera overheats, much more than would be expected from a consumer-electronics product, but to the point of causing physical damage to the plastic case?

The heat problem

Heat in electronics mostly comes from dropping voltage by converting current into it, in our case, the voltage regulator in the Fonera drops 5V to 3.3V at 500mA, resulting in the dissipation of 850mW. That’s right, we are dumping 850mW right into the atmosphere in the form of heat. This brings the operating conditions very close to the maximum ratings for this regulator, which has a maximum rated thermal resistance of 90ºC/W, my calculations put the operating conditions at 88ºC/W. Additionally, the wireless section of the Fonera is also converting a lot of energy into heat.

The measurements

After I finished my tests, I got a comment from Pobletewireless, regarding his own measurements of the heat problem, which are shown in very cool thermographs (no pun intended!) – much nicer than my rather rudimentary method.

I measured the temperature of the Fonera using a thermocouple connected to a Fluke 123 Scopemeter via an 80TK thermocouple module. The thermocouple was placed in between the heatsink and RF shield, the case closed, and the Fonera powered, as can be seen in this picture:

After 10 minutes operating normally, the temperature had risen to an average of 72ºC, with a peak of 80ºC.

The second batch of measurements were performed drilling four small holes to allow the thermocouple into the casing, the locations are shown in the following picture:

Maximum temperature at one corner was 43ºC. Next, an attempt was made to melt the white lid of the Fonera, by exposing it to a high temperature airflow from a paint-stripping gun, and at the same time, applying slight pressure from below. The thermocouple was used to measure at which point the plastic became maleable, and deformation started. At around 100ºC, the plastic was soft enough that a solid object could change its shape – this is in line with ABS plastic thermal properties, which state a deflection temperature around 100ºC, depending on specific material composition.

As the deflection point test resulted as expected, the lid was then exposed to an airflow at 280ºC for two minutes. The result of this exposure is shown in the pictures below:

It’s obvious that some deformation has taken place, with discoloration and charring on the point where heat was directly applied. However, the front side of the lid had mostly retained its shape.

Conclusions

The Fonera does indeed run very hot, much hotter than it should, if anything, for the good of the internal parts. Electronic components are sensitive to heat, with maximum ratings given by each manufacturer in terms of storage and operating conditions. The higher the temperature, the lower the service life of any given component. Some are affected more than others, most notably, electrolytic capacitors have a high sensitivity to heat, as it can evaporate the electrolyte quicker, causing it to fail. The capacitors in the Fonera are made by Taicon, a taiwanese manufacturer, and are max-rated for 105ºC. From the datasheet [PDF], at this temperature, the capacitor will fail after some 2000 hours, around 83 days. Following Arrhenius’ Law, and since the area around the capacitors was found to be at around 52ºC, their expected life would be 7800 hours, or about 325 days – what a coincidence, almost a full year, after which your warranty has expired. Comparing the Fonera to a Meraki Mini, one realises that there is a serious design flaw, as apart from the Mini having a switched-mode regulator, the wireless section shares exactly the same design as the Fonera. The temperature measured outside the casing of the wireless section indicates that the junction temperature of the components inside has to be ridiculously high. So, one conclusion is that the Foneras will eventually fail due to overheating, and it will probably happen sooner than later.

On the deformation / melting video – in my opinion, it’s not real. At least, it couldn’t have happened without the Fonera reaching temperatures around the whole casing that would have caused some components to blow up (for example, the capacitors). The Fonera could not have undergone such an extreme temperature, and still function as shown on the video. The temperature gradient between the heatsink and one corner of the case is almost 2:1, thus, to reach a deformation temperature of say 200ºC at the corner, the heatsink must have been running at 400ºC! A final bit of evidence – the sticker. If you look closely at the video, the sticker on the bottom of the Fonera looks almost unscathed. Here is a picture of what it looks like after applying a 250ºC airflow for 30 seconds, which causes the plastic to deform:

Obviously, a more prolongued exposure would have damaged it even more. In all honesty, I would love to get more details from the guy who made the video, as it stands right now, I’d call it a hoax.

Reading an article in The Register by Bill Ray, he thinks the Apple iPhone will fail, actually, fail badly. I somewhat doubt his conclusions.

The main argument to support his analysis is that since network operators have to like the phone, then Apple has to do a good job convincing them. Remember the ROKR? It was rather a failure due to the fact it could only be loaded with iTunes music over cable, and thus mobile operators were left out of attractive data chargers levied when buying music directly from the phone. There was even speculation that Apple allowed it to launch on purpose, to protect their audio player market.
Where Bill goes wrong in my opinion is that the handset market is heavily controlled in the US, but not in Europe – go to any shop in the latter and you will have a very large variety of handsets to buy unsubsidized. Why? Because a lot of people value the ability to switch operators as they see fit, without having to enter into contracts involving their soul. In the US, there isn’t a culture of operator hopping, but rather of staying with one just to get a phone $50 or $100 cheaper.

One thing I have never understood is why people get themselves tied into a two year contract for a $50 saving. If they worked out how much they could save by moving operators taking advantage of special offers, they may think twice.

There is a very large number of paths Apple could follow, first, they have a nice distribution network with excellent shops placed in key areas, second, they have a large and loyal crowd of followers, who would probably not mind paying an unsubsidized device, and third, there are already a number of MVNOs and fixed-line operators that are willing to take a bite from the large networks. As for the subsidy, I wonder…are iPods subsidized by anyone? Apple costumers are used to pay for quality, and in my view, the iPhone will be no different.

The guys at Pobletewireless have been busy with the Fonera lately, and have now posted a step-by-step hack to add a DB9 connector that allows easy access to the built-in serial port, without having to make IDC cable headers and so on. [Link]

The hack gives access to the console, with which you can do all sorts of nice and interesting things.

Picking up the Register’s story, it seems Linksys has done a really neat PR coup – they have launched their own WiFi phone, and called it iPhone. As you know, there has been a lot of hubbub in the Macosphere the last few weeks about a supposed mobile phone to be launched by Apple, even with rumors of large orders to Taiwanese OEMs. It looks like Linksys beat them to the punch!

Today I was throwing old stuff away from my parents-in-law’s house, when I came across a Casio PB-1000 personal computer, which belonged to my wife. She told me ‘oh, that’s just a calculator I used at school, it used to be good for trig’. In fact, it is a very capable machine (in its time, now your TV’s remote has more processing power than this thing!), it has 8kB of RAM, an RS-232 and floppy drive port, graphic touch screen, and runs for 55 to 100 hours on 3 AA batteries. What really strikes me opening the device is that the keyboard is very similar to the ZX81′s, with all the most used BASIC commands overlaid on each key, and accessible using the shift key. Here is a picture of this ancient device, which brings back many fond memories, such as getting Pong to work:

There is a wealth of information about the PB-1000 on Andreas Wichmann’s site.

Went to my local Vodafone store to pick up the new Huawei E220 HSDPA USB modem, which with a 49 Euro monthly contract gives you 1GB of transfer at 1Mbps maximum, and free mobile to fixed landline calls – pretty good deal if you ask me. For 59 Euro you get 5GB of transfer, at the full 3.8Mbps that HSDPA offers. These are theoretical rates, as they will depend on a number of factors, such as how many people are also using the same cell, your coverage and the quality of the link.
We can argue all we want about how convenient WiFi is, being omnipresent et al, but in reality, it’s rather hard to get connected while on the road. Let’s examine the following scenarios, and you tell me the chances of getting connected over WiFi:

• Riding the train or bus home.
• Getting a lift from a friend in his/her car.
• Opening your laptop at a random location (cafeteria, bar, etc. that you haven’t before scouted for open WiFi).
• On a plane, waiting for the next free takeoff slot that you hope the pilot won’t miss because he was checking the fatness of his wallet.

Let’s be honest – free open WiFi is great once you have identified the locations where you can get connected, such as a friend’s house or the local coffee shop. Other solid commercial alternatives make it easier to find WiFi, as they tend to be present at well-known locations. Walk into any Starbucks or hotel, and you’re bound to find at least for-pay wireless.
For me, on the 30 minutes to 1 hour it takes to get home on the train or bus, being able to get connected is great. The convenience of simply opening the Mac and getting online beats the guesswork of WiFi. I tried getting the Mac working with my Nokia N93 over Bluetooth, but it was just too unstable – one day it worked, the next simply refused to even connect. A more in-depth review of the device is coming, once I get a chance to roam about with it for a while.

So far, installation on the Mac was pretty straightforward, download the setup package from Vodafone’s site (they don’t tell you this in the manual), which then enables the modem as a networking device. If you don’t follow this step, it can get recognized as a storage device, which is not particularly useful for a modem. The one thing I don’t understand is why it comes with a miniUSB cable that ends in two USB connectors, my guess is it’s power-related (some USB ports don’t provide the full 500mA they are supposed to provide).

The Register reports that BitTorrent has come to deals with three consumer electronics manufacturers in order to develop devices with an embedded BitTorrent client, thus bypassing the PC and freeing it to do other tasks. This would be specially useful to laptop users, who don’t want their mobile computer immobilized by a large download.