Randy Glenn is possibly RoHS Compliant, but only by exemption.
Xilinx has an interesting article on embedding instrumentation in a design for field debugging. Within that appnote is an interesting section that gives you the building blocks you need to start designing your own logic analyzer:
Embedded Instrumentation Using XC9500 CPLDs
Naturally, there’s still some work to be done with it, but it’s a decent enough start.
So it seems the Pidgin IM project is run by a bunch of jerks. Read here:
http://developer.pidgin.im/ticket/4986
A summary:
It’s obvious from some of the comments that the users are at times going a little overboard, but there’s no excuse for the developer response (which, to date, has been “It’s our project, nyah!”).
To all developers: these are your users. Without them you are nothing. If they say the “feature” is crap, it’s crap. People who make software for money, by and large, get this point, lest they finally learn their lesson when they’re out of a job. One can only hope that by removing this motivation for Open Source projects, they have not doomed themselves to a future of of irrelevancy.
Remember kids: ideological purity is for philosophy students. Everything in reality is a compromise between an ideal design and what actually works.
Charging batteries properly is more difficult than you might think, and definitely more difficult than cheap power tool companies engineer for. The simple lightweight charger that comes with a cheap cordless drill is almost assuredly a piece of crap that will kill the batteries in short order.
Smart chargers monitor the state of the battery to cut off charging at the proper time. For NiCd and NiMh cells, this reduces cell damage. For LiIon cells, it reduces explosions and generally highly-exothermic scenarios. Atmel’s got a decent appnote on some of these algorithms:
AVR450: Battery Charger for SLA, NiCd, NiMh and Li-ion Batteries
Now you can build your own, and keep from having to buy a new drill just to get a new battery (that the store you bought it at no longer has / wants 80% of the price of the drill for).
I once had an idea for a portable speed-dial device that you held up to a payphone to dial any of, say, 100 stored numbers. Software with that capability on PDAs were the first nail in the coffin for me on that idea; that someone had done it before, along with the whole rise of cellphones thing, pretty much sealed the deal. This would still have been interesting to read back then, though:
The appnote basically gives the derivation of a DDS system for DTMF signals, and the included flowcharts and descriptions would make this a snap to implement on any microcontroller, Atmel or otherwise.
A very cool project: someone’s taken an ATMEGA168 and written a bootloader that emulates the USBasp. This allows it to download code directly over USB – with no on-chip USB peripheral or other USB chip – using a programmer protocol already supported by avrdude. The whole thing fits in 2KB of Flash space.
What this means, is you can make an Arduino-alike, with only one IC (save for the voltage regulator), which still works with the Arduino software for downloading (make a small configuration change). The only disadvantage is that you lose 3 I/O pins during bootloading, and you don’t get a USB-Serial channel back to the PC.
The Metaboard – check it out. Uses the USBaspLoader from Objective Development, who developed the AVR-USB software USB framework.
Saw this linked from EMSL: The coolest watch ever.
I only hope the guy updates his site soon – I want to see what went into getting it done.
A really cool article: Making your own illuminated buttons. A pretty cool technique, and doesn’t use anything overly esoteric.
Maxim has an interesting appnote on driving a bunch of LED displays using fewer I/O lines than normal
Charlieplexing: Reduced Pin-Count LED Display Multiplexing
An interesting approach to multiplexing the segment drives with the digit drives for multi-digit LED displays. It’s easy enough to implement on your own microcontroller, though unfortunately you don’t get the nifty constant-current driving that Maxim’s chips give you.
Continuing on my high-brightness LED kick, here’s a few designs for switch-mode constant-current supplies for high-power LEDs, courtesy of ON Semiconductor:
12V AC-DC MC34063 LED Buck Driver
The MC34063 is a nice chip to use purely based on price – it’s dirt cheap. You can also get a fair amount of efficiency from it, though apparently the darlington output stage is somewhat lacking. Still, it’s available in a DIP8 package, and did I mention… dirt cheap? $0.83CAD from Digikey in singles, drops to under $0.30CAD in the thousands.
Considering that any linear system (constant-current regulator, plain ol’ resistor) is going to give you something on the order of 50-60% efficiency, and this’ll give you on the order of 75-85%… not bad at all.
If you, like me, are using the excellent SCPlugin for Subversion on OS X, and also have your own Subversion server with a self-signed certificate, this thread is of interest in Getting The Damned Thing To Work™