Version 3.01 release notes

A major change justifying a new version number is addition of a Surface Mount Technology (SMT) version of IRK!. I haven't completed assembling the SMT version, so it may have bugs that need fixing (and it might not actually work!).

The original Through Hole Technology (THT) version is unchanged as of v2.11 and all its files have been moved to a directory called /tht. A new directory called /smt has been created to house all the new SMT files.

The SMT version uses a PIC18F25K50 microcontroller instead of the THT version's PIC18F2550. The main difference between the two is that the PIC18F25K50 does not need an external crystal, so that frees up two pins (RA6 and RA7) for other functions. At the moment only RA6 has been re-purposed as an "Auxiliary Switch" output and RA7 has been tied to ground. The 2N7000 MOSFETs that were used by the THT version to switch Power and Reset have been replaced with a 4066 Quad Bilateral Switch IC (e.g. MAX4066). The 4066 has four independent bilateral switches which behave much more like real switches than the 2N7000s. For example, polarity is not important. In the SMT version, three of the four 4066 switches are used - one each for PWR, RST and AUX. The AUX is an auxiliary switch that you can use for anything. Actually, they can all be used for anything, but the intention was that PWR would parallel the PC power switch, and RST would parallel the PC reset switch. Just think of them as three things you can "switch" somehow by pressing a button on your infrared remote control (the "somehow" is up to you ...and with a maximum switching current of only 50 mA, you can easily destroy a 4066 if you're not careful).

I've had a few SMT boards manufactured in China by "iMall ITEAD Studio" and the build quality is excellent. I still have to solder the components onto one of the boards and see if it actually works. It should work, but you never know until its built.

Posted by Andrew Armstrong 2013-12-11