eZ430-Chronos Wireless Watch

Jay L. said:

Is it possible to add a vibrating alarm for the eZ430-Chronos Wireless Watch?

Possible, yes. Easy? no. For vibration, you'll need an ocillating mass. Driving it requires energy, and the mass itself and the driver requires space. Both is scarce on the chronos.

Anyway, there are two possible approaches. The typical vibration was done by using a motor with misadjusted load. Once it starts turning, it vibrates. Simple, cheap (you can get them for a fer cents) but large (not for older cellphones but for newer ones) and energy consuming (also not a problem for older cellphones with their large accu cells, and not a problem for newer cellphones with their smaller but more capable accu cells). But not really an option for the chronos.

The other approach is the usage of a low-frequency speaker signal. Here the problem is that usual signal speakers are piezo-effect speakers. They have a lower cutoff frequency way above of what you would feel as a vibration. Also, they don't have enough mass to produce a noticeable vibration amplitude too. You'll need a magnetical speaker that will swing on as low as <50Hz (25Hz or below would be best), small enough to fit into the chronos and heavy enough to pose a noticeable oscillation.

Driving it from a chronos PWM output wold be easy and the 10mA drive capacity of the chronos port pins would be more than enough.

hi!

I am new in eZ430 chronos, but I think I'll have the same problem.

besides, in the FAQ section I read that 'all pins of the CC430 were used for the LCD, buttons, or sensors', which is quite disturbing!

so, I thought I'll need to drop something out... let's say... remove (physically) the pressure sensor and replace by a coin-shaped (pancake) vibration motor. what do you think? maybe we need to use a power FET as driver (SOT23, piece of cake...)

if you move any further, please leave a tip.

adelk prado said:

I read that 'all pins of the CC430 were used for the LCD, buttons, or sensors', which is quite disturbing!

There's much in the watch, so no wonder all pins are used. That doesn't mean you cannot reuse them. SPI and I2C are bus systems. So you can attach additional devices, even drivers to them. Also, you might be able to multiplex xome functionality. e.g. the pushbutton pins. If you check whether the button is pushed or not, you can use them as outputs while they are not used to detect the button press. Not easy, but possible.