TI Launchpad

Recently I've been trying to do battery powered devices and I came to the conclusion that there is more to it than you first think.
My experience with the Bird-O-Matic is that it each battery lasted only 25% of what I had planed. There were some options that might have influenced it:

• I didn't made an OFF timer, once the PIR detects an warm object it turns ON the MP3 player and the Amplifier for some time (7-10 seconds), placing a forced OFF timer of 20-30 seconds would prevent constant re-triggering every time someone passes by.
• Was the use of a CMOS 555 better than a micro-controller? Today's controllers consume almost nothing in standby or power down mode, and a wake up on pin changed could be used with the PIR.
• The external MP3 player consumes a lot of power and takes 1-2 seconds to start up. It was the simpler and fastest solution, but not the best for power saving.

Recently I read about the MSP430 ultra low power capabilities and I wanted to try them out. The Texas Instruments Lauchpad let's you do just that at a very low price (about 10EUR) and a big Windows installation (see here). I admit I'm always very reluctant to install windows software but unfortunately these links for installing in Linux didn't work out.


It is a bit sad, but I'm no sysadmin and no I don't know perl and I don't want to lose time learning perl, to correct a script, to install a msp430-gcc, to program devices... I understand the technical difficulties behind maintaining and supplying a gcc distribution (specially if also sell a payed tool), but nowadays it is becoming a "must". Sounds like when AMD started giving away PALASM... suddenly every PLD manufacturer started doing it or... went out of business..
After installing the correct tool (the free version is not the latest version), I followed the start up guide and sure enough I made my first C program.
The tool is simple and powerful (based on eclipse), in Windows everything works mostly out of the box.


The board is "divided" into a emulation tool and the experimenter board where devices of 14 and 16pins can be connected. There's also the option of soldering (an included) SMD low-power crystal oscillator. Instructions are also provided on how to measure the power of the experimenter processor, although it is tempting do not cut the board through the dashed lines.. it will not work as a MSP-ISP... that's another tool. (but I guess removing the jumpers and direct connection is ok :-).
The processor although a 16bit simple RISC architecture does appear to be quite capable, I just tried out a couple of examples in C. This though is not what I want to try out... I want to see if the operating current is as low as "advertised", but that will have to be for a another post.

Christmas Ball (the 11.11.11 post)

It is a bit late to announce but we won a prize!!!


Huyser bookstore in Delft ran a competition to promote the book from Arne and Carlos "55 Christmas Balls to Knit", see the promotional video here. Just before the deadline (1.11.11) our son Daniel was born, but we managed to find time to finish the Ball and submit it.
Naturally Ana chose a pattern and knitted the ball, I took care of the electronics. We were so late entering the competition that we only have "night shots" before submitting the ball...


It is a simple ATTiny15L powered with 3x AAA alkaline batteries.
There are 4 LEDs connected to the ATTiny, each in one of the reindeer's nose.
I've made a 32bit pseudo random number generator with a LFSR. The ball to lit is randomly picked (1..4) and also the fade-in time (1-2sec), fade-out time (1-2 sec) and off-time (2..4 x 2.5sec i.e. number of watchdog cycles).
The average measured power consumption is 1.5mA so one can expect about 1000 hours of operation from 3 standard cells.
(click on the circuit for a better view)


The schematic is not exactly this one, this is for another project that hopefully will come out before Christmas, just remove the solar charger, the voltage measuring and that's it!
We got the third prize, 100EUR in books!!!

Balcony Crop 2011

Winter is coming and I almost forgot...
This year crops were not better than last year, and considerably less than the first year, the ground in the vases is getting "worn out" and too compact so vegetables that grow in the ground (carrots and turnips) don't grow that much.


Still we managed one (yes, only one) bowl of steamed vegetables (150g). This year Luísa helped picking up the carrots.
The "top of the crop" goes to the turnip followed by the micro-carrot.


Unfortunately, the beetroot did not survive the very dry and hot spring followed by a damp and lousy summer...
I'm now awaiting for everything in the vases to dye out and then I reinforce the soil or change it all together...

FireFly Jam Jar

I wanted to build a night-lamp for Luísa, something a bit less "spooky" than a blue IKEA Spöka that she has. I also wanted to be able to charge just by placing it in the sun (even there isn't much of that up here)...
I went back to my stack of old ATTiny15L and designed a circuit with four LEDs connected in a particular way that only used 3 pins to lit each of them. The other two measure external light (light on when it is dark) and battery (low bat... do nothing be very very still).
I got some jam jars and some Yellow/Amber LEDs and started programming, for the battery I selected a 3.6V 50mAh NiCad (i.e. junk hanging around) and the battery charger was a two transistor current limiter but after some tries I settled with a simple schottky diode from the panel to the battery.



The idea of the project is that when night falls (or lights out) the light goes on for about an hour hopping from one light to the other with different ratios of fade-in and fade-out. This hopefully will induce a sleepy feeling (like candles... by the way.. simulating four candles is also possible)
The schematic is the same as for the reindeer ball project, but this time I went "all the way" to a PCB FAB. I still have to wait for it to come but it looks nice in the preview.



It is my first "non-rectangular" board and actually my first milled board. We'll see how this project will look like in the end...