Simple Timing Circuit

[Zapp Brannigan]

Hi -

I need to devise a simple USB-powered circuit that briefly activates - maybe a 1sec pulse every 5-10mins. I think that a 555 IC in astable mode is the right starting point, with a capacitor to hold power and resistors to handle the delay. If anyone's aware of a suitable circuit diagram or could make suggestions, that would help me a lot.

Background of this is that I'm finding my hand cramps on the PC mouse if I don't periodically flex it. I'm left-handed, so use a mouse slightly diagonally, for long periods of the working day. I've tried reassigning the buttons, but I can't overcome decades of habit (especially when I have to use ordinary mice on other PC's sometimes).

I've experimented with a clockwork egg-timer and it works as a cue, but it's a PITA and offends my sense of tidiness. So new plan is to install a little buzzer, or maybe a tiny vibrate motor from a cellphone, inside the body of the mouse.

Thanks in advance for any ideas - Z

[Graham.]

Handy time consent calculator for the 555

can't help thinking you might have a commercial patentable idea there if no one has got there before you. You've seen those H&S warnings about RSI that come with keyboard etc.

How about a mouse that delivers a T.E.N.S. style electric shock?

[Frank Erskine]

help a bit It might pay you to use a 556 (dual 555) to give you a specific output duration., although an astable with your required parameters should be possible with a 555. For long durations use tantalum condensers rather than simple electrolytics

Is there any specific reason why it has to be USB powered?

[Graham.]

Because he wants to build it inside a mouse.

[Andrew Gabriel]

Swap to using the mouse with the other hand. It takes about a week to get used to it, but thereafter you are mouse ambidextrous and can switch hands to give one a break.

Also, you may be using a mouse which is too small for your hand size.

[Chris J Dixon]

How about a completely different solution.

free program creates virtual post-it notes - handy for lots of types of reminders and lists.

You can set them to re-appear at any chosen interval from 1 second to years, and also choose an audible alarm to accompany them.

Chris

[Nick]

In message , Zapp Brannigan writes

Possible less technical solution ... I've had to start using a support mitten thing for my right hand, which was locking up on the steering wheel during long distance driving. It's got enough tension to remind you to loosen grip quite frequently. I can imagine a number of others uses being suggested for it soon, too...

[ARW]

This thread made me go into the loft and fetch down my old copy of IC 555 Projects by E.A Parr.

Zapp, if you want the book then email me and I'll post it off to you. BTW it also covers (to a small part) the 556 timers (and it also tells you how to make a Star Trek "Red Alert" sound, should you need to.)

Cheers

[Andy Burns]

Gnome has a built-in "typing break" feature, which forces you to stop using the mouse and keyboard regularly, I've never used a Windows equivalent, but they seem to exist, e.g.

[Dave Liquorice]

Or dump the mouse entirely and use a proper track ball. Keeps your fingers moving and doesn't wander about your desk space, need picking up whne it has wandered or need a flat clean/clear area to occupy.

Check out the offerings from Kensington. I've using a Kensington "Expert Mouse" trcak ball that I bought in the US in early 1993. Had to replace the left click microswitch one and it sort of needs doing again but it's a standard component microswitch.

ain't cheap compared to a mouse but they are *much* easier and nicer to use.

[Brian Gaff]

I'd have thought one of those talking timers that reset on hitting one button might be annoying enough to do the job, though you might need to alter them to use the usb to save battery costs. Brian

[Bob Eager]

Yes, well worth doing. I have some PCs with the mouse on the right, and some with mouse on the left - so the 'wear' is evened out!

[Peter Parry]

Would the free Workrave timer

be any use?

[John Rumm]

How about a software process that periodically inactivates the mouse, and replaces the pointer with a "rest" icon?

[geoff]

In message , Zapp Brannigan writes

Can't you find a countdown timer program that will just flash a message on the screen

"PUT THE MOUSE DOWN AND STEP AWAY FROM THE COMPUTER"

why do you need a hardware solution

[Tim+]

We have a "compact" mouse that gets used with a laptop occasionally. It's amazing how quickly it can induce cramp.

Tim

[rbel]

I use an Evoluent Vertical (V4 wireless) mouse that includes a variable software break timer that produces sound and/or visual alerts and an optional 'it's time to resume work reminder. I have found, however, that since I have been using this mouse I have not needed to take RSI related breaks.

-- rbel

[polygonum]

Funny how we vary. I use a Logitech nano notebook mouse by choice - regardless of whether desktop of lappie being controlled. With the sensitivity turned quite high, I can control it almost entirely by finger movements (rather than whole arm) and find it the best I have ever used. Changing from finger-straight to finger-crooked is enough for the pointer to travel the entire height of my screen. My hands are very wide so the hand-to-mouse-size-ratio could certainly suggest the mouse is too small.

In work situations, when someone else tries to use my mouse, they usually run away screaming... (So I often have a second mouse, with more conventional settings, connected.)

[Dave Liquorice]

Sounds like you are using that mouse more like a trackball. B-) Finger straight to crooked on the trackball here is half the screen height. A real track ball has the advantage it's always in the same place and doesn't drift if the cable gets half a micro Newton of tension in it.

[Jules Richardson]

Yep, that's happened to me, too. Plus I'm a lefty and it's surprising how many mice are sculped to fit better in the right hand; the older ones are more likely to be symmetrical and hence more comfortable to use.

Oh, and the mouse on my wife's PC seems to have the pads upon which the mouse rests set quite far inboard of the edges - which means that in use it feels like it's tipping over and so there's a tendency to hold it rather delicately, and that in turn makes it uncomfortable after a short while.

cheers

Jules