haptic driver details
Hi,
My application requires a fairly powerful haptic driver. I was considering a 10x4mm LRA. I'm wondering what the compatibility of the Metawear R series boards is with different LRAs and vibration motors? What is the voltage passed to the motor from the board, etc... and what other considerations should I keep in mind? Can you recommend some compatible vibration motors?
Thank you.
--Alex
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Comments
That larger pancake motor would work with MetaWear. The typical way to connect the motor is via the 3V pin next to the high current driver. The other important constraint for a motor is the drive current -- the default battery we provide is 100mAh and supports a maximum 1C discharge or 100 mA in other words. If you were to replace the battery with something larger, then the 3V regulator would be the next limiting factor at around 150mA. You should keep in mind to allow a little margin in your budget, maybe 20mA for other peripherals like the LED and radio. The specs are all further detailed in the MetaWear data sheets.
If you have a motor that can support up to 4.2V, you could directly tie the motor to the battery voltage. To do this you would need to remove the protection diode from the HCD driver circuit and add one across the motor. Then your maximum current would be limited by the battery and HCD driver -- As described above you could use a larger battery to increase current, and the HCD driver can support close to 300mA. The downside with directly using the battery voltage is that it drops as the battery discharges, so your vibration intensity will not be consistent over the battery life.
Matt