A Nation of Frustration

Okay, so soon after I last posted, I started toying around with my old AVR mkII ISP programmer to see if I could get it to work again. It worked at some point in the past, but I've reformatted my laptop since then.

I will spare all the details suffice it to say that I spent about 4 hours trying to get the development environment set up, and for like 8 seconds, everything was swell-ish.

Doing Digital

So, earlier, I expressed an interest in changing my analog accelerometer to a digital one. I found an excellent candidate, the LIS33DE by ST devices, but it had this weird footprint.

My analog accelerometer claims to have a 4x4mm body LGA-16 footprint:
And the digital one has a 3x3mm body LGA-16 footprint:

The LED that burns twice as bright burns half as long

I was doing a little napkin-math to see what my power/space constraints would be.

Reading the specs of the CR2032 battery, I found that the maximum rated continuous current is 1mA and the max pulse current is 10mA. Typical full-size LEDs take something like 20mA. But even if the LEDs only took 5mA, that's too much when you factor in all the other crap on the watch.

I'm not too worried about it at the moment though. I'm assuming I can push the battery a little because I won't be drawing boatloads of current out of it continuously. I took the back off my binary watch and found that its massively bright bank of LEDs runs off a CR2032 and it might have up to 8 LEDs on at a time.

When is a wrench not a wrench?

So it turns out not only was the wrench not needed, but if it was, I got the wrong kind. All of the watches I've dealt with are opened by prying off the backing. This is how I've destroyed a number of screw drivers, so I thought a dedicated tool might do a better job. Turns out I was wrong. This wrench is for "jaxa" style watches which have little grooves on the backing which line up with the wrench. The back is then unscrewed.

Whoops. There goes $6...
Edit, actually, someone on my hall has a slide rule watch which wasn't slide ruling very smoothly. Using my new wrench, I was able to take the backing off her watch and apply some lubricant to the slide rule gear. $6 well spent.