Brickbats
From time to time I buy or use something in the electronics world that does not work or is a waste of money and/or time. Generally I write the incident off to experience as the problem could be due to my unrealistic expectations or just an unlucky occurrence. But sometimes the experience is so bad that I believe that I should warn others before they waste their money or time as I did.
Rather than dedicate a number of web pages to negative subjects I decided to group them all together in the one page with just a paragraph or two summarising my point of view.
So here they are, my personal brickbats...
FTDI and the 232RL USB to serial bridge
A USB to serial bridge is a chip that provides a TTL serial interface on one side and a USB interface on the other. On EBay there are hundreds of suppliers selling devices based on these chips for as little as US$2. I use a lot of them with the Micromite because they allow you to connect a PC with a USB interface to the Micromite's serial console for editing programs, etc.
One of the most popular of these chips is the FTDI FT232RL, in fact it become so popular that copies or clones of it appeared on the market These clones worked with the standard FTDI drivers and most users were unaware that the device that they had purchased contained a genuine or a cloned chip. For example, one is illustrated on the right - can you tell if it uses a clone chip?
FTDI then made a most stupid decision and decided to punish the users rather than the clone manufacturers. They did this by releasing a new Windows device driver that not only refused to work with a clone chip but went further and crippled the chip so that it would never work again with any other computer or driver. To make matters worse Microsoft included this driver in an automatic Windows update with the result that thousands of people suddenly found that their USB to serial converters had stopped working and were worthless.
There were no questions and no warning. Just whack! Essentially FTDI reached into other people's computers and destroyed their property. This is exactly what a computer virus does... and it came from a respected British company. The backlash was enormous but FTDI remained unrepentant.
The problem is that you, as the purchaser, do not know if the vendor offering to sell you a FT232RL based bridge used the genuine chip or not. You will only find out when you receive the device and try plugging it into a Windows computer. As a result you should not buy a USB to serial bridge using a FTDI chip. FTDI may have won this battle but in the process they have killed one of their product lines along with their reputation.
Postscript: I now recommend USB to serial bridges based on the Silicon Labs CP2102 chip. They are cheap, work perfectly and do not carry risk of being remotely crippled by FTDI.
Windows 10 Update
I quite like Windows10 and I admire Microsoft for trying a different business model and essentially giving it away for free. But, they have gone overboard in their efforts to get everyone to update and then subsequently control what you can or cannot install on your PC.
I was overseas (in Ireland) at the time that Windows 10 was released and the "Update to Windows 10" icon appeared on my Windows 8.1 laptop. I was using my mobile phone in tethering mode for my Internet connection and had a limited data allocation, so I did not agree to the update, instead I planned to do it when I returned home where I had an unlimited data allocation.
What I did not realise was that Microsoft had ignored my wishes and silently installed software on my laptop which commenced the 3GB download anyway, without asking and without warning. The first that I realised that something was amiss was when my whole data allocation had been consumed within a few days. I then had to purchase an extra data allocation and that was consumed again before I found out what was going on.
In their rush to get me (and millions of other users) to upgrade to Windows 10 Microsoft treated my computer as if it was their property. And it goes further, in Windows 10 you cannot turn off the automatic updates. So Microsoft now has control over my computer - they can install whatever they they want and they can uninstall whatever they don't like. As the debacle with the FTDI drivers (described above) shows, they can even let a third party (who I have no connection with) into my computer and disable any hardware that this third party does not agree with.
All without asking and without consultation. This is big brother behaviour and does not bode well for the future.
Hands-On ZigBee by Fred Eady
Subtitled "Implementing 802.15.4 with Microcontrollers" and promising to provide an in depth look at the IEEE 802.14.4 and ZigBee standards I thought that this book would be a good start in this area. It was very expensive at almost A$100 but the blurb made it sound worth while. Amazon have it cheaper (here) but don't bother, even at $1 it would still be an amazing waste of money.
In total the book has 351 pages but of that only 34 pages actually describe the IEEE 802.14.4 protocol. The rest is padded with reviews of various evaluation kits from manufacturers and pages and pages of code and the output from a protocol analyser. If that was not bad enough he finishes the book by describing the Cypress method for implementing touch sensitive buttons - what has that got to do with wireless networking? I suspect that he had already written that portion (probably for a rejected magazine article) and decided to throw it in on the basis that most people would have given up on the book long before they reached it.
He writes in the over friendly style of a con man who knows that he has a victim. The most annoying part is that the small amount of the book that actually addresses the subject matter (34 pages) is poorly written, confusing and incomplete - he does not even describe the ZigBee protocol.
The Chumby
The Chumby from chumby.com is a compact device that uses your Wi-Fi network to download useful data from the internet and display it on a 3 inch touch sensitive screen. I thought that it would be great for showing the current weather and forecasts, news headlines, etc. Above all I thought that the concept was wonderful - a small linux appliance that was constantly in touch with the internet and summarising just what you wanted to see.
Unfortunately it did not work out and I consider the A$160 (including an expensive freight charge) totally wasted. For a start the wi-fi networking has a very limited range, it must be within a few metres of my wi-fi router to pick up a signal. Secondly the linux/hardware combination is very unreliable, the Chumby will only run for a day or two before locking up. And, when you do reboot it, you are forced to go through an extensive and agonizingly slow set of menus to reconnect to the internet.
Even when the Chumby is running the concept is flawed. The tiny screen can only show a small amount of data and if you instruct it to automatically flip between pages you will find that inevitably the page that you want is not showing when you look at it (assuming that it has not crashed in the meantime).
What a pity, a good idea but poor execution.
UPDATE: Chumbly.com has gone out of business - it seems that the market has agreed with me.
Design Warriors Guide to FPGA by Clive Maxfield
Another expensive book (amazon page) that is a deep disappointment. The start is promising enough and he does an OK job of introducing FPGAs at a high level but the latter half of the book is padded with material that is only vaguely connected with the subject. If you are looking for a high level introduction without detail then this book would be OK but it promises much more. It would be better condensed into a small booklet or a long magazine article
This is another bad book from the publisher Newnes. They are risking their good name.
Deal Extreme
Deal Extreme (dx.com) is a Chinese on-line retailer who has a huge range of items (reportedly 160,000) mostly at very cheap prices. Often the quality will match the price, for example I purchased some USB to RS-232 converters for $4 and they were so sensitive to the USB voltage that most died in the first month. But normally such a converter will cost $25 to $35 so I figured that I had got what I had paid for.
But it is not the occasional cheaply made product that earns them a brickbat, it is their review system. 
Deal Extreme encourage their customers to review any products purchased and I have done this several times for various gadgets that worked particularly well. But when I purchased a charging mat for my Galaxy S4 phone I was disappointed to find that it did not work properly - the phone kept dropping in and out of charge. I replaced it with a different brand from another supplier and that worked perfectly, so the Deal Extreme product was not up to scratch.
At US$21.31 the charging mat was not cheap so to warn others I entered a review titled "Does not work with my Galaxy S4". As you may have guessed, Deal Extreme refused to post my review while leaving in place three other customer reviews that were more favourable.
This is dishonest to the extreme and earns them a solid brickbat.
You Are Here 
Unfortunately another poorly written book that insults the reader. You Are Here purports to be the history of navigation but after an interesting and good start the author (Hiawatha Bray) starts to pad the book with irrelevant and false information.
I know for a fact that in one area (the story of Wi-Fi) his description is wrong and completely misleading. He spends many pages falsely describing the development of Wi-Fi as being the work of the US company NCR, when in fact the key technology came from many organisations including the Australian CSIRO who hold a series of patents on the technology.
It is hard to see why he did this - it could have been poor research or more likely an unethical effort to make the story more interesting - but it does mean that the facts in the rest of the book cannot be trusted. This is a disgrace as the entire book then becomes worthless.