Ask: Lack of grounding may cause USB mouse to go nuts!

This is the third USB mouse that has gone nuts. After roughly what may be two, three months of buying and using, the mouse starts to frequently send two signals instead of one back to the CPU when the left button is clicked. The end result is that instead of a single click, a quick double quick operation is performed, which gets thoroughly annoying considering that your applications start to magically close, fail to minimise or maximise, or any number of other behaviours.

Blaming the USB mouse of being faulty and of inferior quality, I would have bought a new one, had it not been for the comment Tili made where he acknowledged having experienced pretty much the exact same behaviour before. He postulates that the cause was likely the lack of grounding in his case. He might not be entirely off-base with that theory. I don’t have grounding at home. Consequently, I can get bitten on my bad days by current dancing on metallic surfaces, not least computer chassis. Though I use the USB mouse in question with my laptop as an external device, I have felt charges on metallic portions of the laptop before. Could it really be the lack of grounding that is messing up the circuitry inside those mice?

What do you think? Have you had similar experiences? Or, do you think Tili and I have nothing better to do with our time?

Symbian: iCode for ‘Enter’ and ‘c’ keys on Nokia phones.

The following won’t make sense to most of the people reading my blog. However, hopefully, it will help out fellow Symbian developers from pulling off their remaining hair looking for the solution I break out in the space of this post.

Nokia phones have a ‘c‘ key which mostly deletes selected items or text. They also have an ‘Enter‘ key, which is mostly in the form of the somewhat bigger middle button on the navigation pad. Symbian developers looking to catch signals when either of those keys are pressed would be hard-pressed to get a taste of success.

One would think ‘EKeyEnter‘ and ‘EKeyDelete‘ would be the right iCode values to catch the ‘Enter’ and ‘c’ key events, respectively. However, that’s not how it works. Surprising, I know. With the help of jelle on #symbian (irc.freenode.net), I found out that the iCode for grabbing Enter key event is ‘EKeyDevice3‘. Similarly, ‘EKeyBackspace‘ is the iCode for the ‘c’ key event.

It is as weird as it gets. But being a Symbian developer, you know this is nothing in the face of the greater bizarre things that make up the Symbian OS.