• Hint : 
• Did you buy a X'mas hat with blinking colour LEDs last Christmas?
• Find it and dis-assemble it, inside it is also a COB with simliar design.

It uses only a few additional components. It  operates at 3V - 5V (so your Palm can drive it easily). The power consumption is low. I have measured the current is just 4.1mA when connected to Palm.  So it will not over-load your Palm V battery during Hotsync, even without the power charger connected to your cradle.

The flash order can be set sequentially or pseudo-randomly.
I chose sequential blink so I soldered a 0-ohm resistor between pin 7 (Vdd +ve) & pin 8 (SEL2).
For the flash  frequency, you can adjust the resistor connected to Pin 5 & 6 (OsSC1 & OSC2). I used a 1M resistor.

Pin 9 & 10 is all connected to the Ground Pin 13 ( Vss/-ve).
The following Pins are connected to the SMD colour LEDs
Pin 1 : Red LED x  2 (Datebook + Memo buttons)
Pin 2 : Yellow LED x 2 (AddressBook + Todo buttons)
Pin 3 : Green LED (Down button)
Pin 4 : Green LED (Up button)
Pin 14 : Blue LED (Palm power button)

You can design other flashing pattern to suit your favour.

The most tedious work is soldering the small tiny SMD LEDs with coated copper wires and fixing them to the clear-colour plastic button. 
 

For the power button, I drill a small hole inside to insert the Blue SMD LED to the inside of the button.

Power the Blink5
The Blink5 is activated during Hotsync through Pin 4 of the Palm V socket, which has a +4.1V to power-up the COB operation.