The battery pack manufacturers are, in my humble opinion, scamming the general public into buying expensive battery packs when they don’t need to.

I’ve a Fujitsu Laptop that I use in spurts. Sometimes it’s in daily use being lugged around with me constantly, other times it gets left on the table under a pile of paperwork and not used for weeks at a time.

Recently I switched it on and the battery was flat and then found that it refused to charge. It’s around four years old so I thought that it had probably just come to the end of its life. The Laptop kept saying it was 98% charged but the charge indicator wasn’t illuminating.

I wondered if perhaps just one of the cells in the pack had failed (and the others could be useful for other things) but then I had a thought; I’ve seen this before with other so called “smart” battery packs. I took out my trusty Dremel power tool and carefully cut into the pack where I suspected the intelligent battery monitoring circuit was.

Once I’d cut into it, I could see the two connections going to the cells and placed a volt meter across them. The pack was reading 9.1v.  

I set by bench top PSU to 11v and hooked it directly across the terminals. I applied power for around 5 seconds, removed it, waited a few seconds and repeated a few times. After each cycle I would check the pack voltage and slowly it started to climb. Once I got the pack up to around 10v, I quickly inserted it back into the laptop and switching on the power. Hey presto, after a couple of seconds the charge indicator came on and Windows reported the pack was 4% charged… and charging. I left it charging whilst I got on with other activities keeping a fairly close eye on things (these retched batteries have a habit of catching fire) and after around 90 minutes or so, Windows reported the pack was fully charged and this was confirmed by switching off the mains power and the laptop happily running on its battery pack whilst reporting around 90 minutes of run time available. This is about right for this laptop.

Hindsight is a wonderful thing sometimes. Like may people, I've designed and built projects only to realise; usually when it's too late, that some slight changes or "tweaks" would have been of benefit to the project.

One of these projects is the breadboard PSU. A slight change to the PCB foil layout frees up some additional space on the breadboard. I've just updated the download file for this project with an additional PCB foil.

Another project that I'm in the process of updating is my recent LED clock. I realised after construction that there were a couple of unused I/O pins on the PIC that could be very useful if they were brought out to one of the connectors. There were some other design improvements that became obvious once I started looking at other things I could do with the project.

Of course, a lot of these types of issues are because as hobbyists we don't peer review our designs. At work, all hardware and software projects are looked over by somebody else on the team; a form of sanity check, and it's amazing how a fresh pair of eyes can spot obvious omissions and mistakes.

Now it's not often that I see a piece of tech that makes the hairs on the back of my neck stand on end, but when my friend Max Maxfield send me the link below, that's exactly what happened.

It's called Pixy, and I really really want one.

Read the full article and watch the demo video here:
http://www.eetimes.com/author.asp?section_id=36&doc_id=1319338

They have it connected to an Arduino but no reason why you can't drive this from a PIC, Raspberry or anything else for that matter.

I've got a thing for clocks... I wonder if it's because I'm not getting any younger.
Anyway, I had a day free over the weekend and decided It was clock building time.

There's not much to this clock really. A PIC18F25K22 running some simple firmware written in AMICUS18 BASIC. There's a Dallas DS1302 RTC chip with battery backup, and a handful of other components.
I've been experimenting with different firmware to see which makes the display the most readable.
The image on the left of the clock front is showing a time of 10:20:13

UPDATE 29/10/13
I've created a construction project for this clock which can be found here.