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DRV2605L: Haptic Motors are getting very hot

Part Number: DRV2605L

Hi,

I'm trying to figure out why the pancake ERM's I am using keep getting hot. I've swapped manufactures, all the boards, 2-3 ft wire, etc.

I'm using a Flora board, i2c multiplexer, driving 6 DRV2605l boards ( all from Adafruit)

I've been back n forth with them over this to no avail.

I created a PCB board to eliminate the proto board.

The motors are rated for 5-6 v.  I've taken them apart to verify they are erm's.

They are usually fine for about the first 5-10 minutes... after that they get hot for about 3-5 seconds and cool off for 5-10 seconds and right back to getting hot (too hot for bare skin).

I'm at my wit's end... I had had the same setup and code for the past 6 months (used for hours at a time), now it's out of the blue things have changed... The DRV boards are not hot, they are pushing 5v at the out pins.

The code is fairly simple, I'm using the library for effects. I started with adafruits code... started having heat problems and played around with the TI code thinking is was the latter

Can the C++ code actually make it get hot? Using Arduino..

An thoughts and reasoning would be great

Thanks for your help

Jim

  • Hi Jim,

    Are driving the ERMs for extended periods? Like 10 mins? Or are you doing some type of ON/OFF intervals?
    It sounds like the motor is breaking down and the coil resistance is maybe dropping, therefore more current drives through the ERM making it heat up. This is just a guess though. I would work with the motor vendor to resolve your issue. It seems the DRV2605L is doing its job correctly.
  • Hey Kelly,
    thanks for getting back... the DRV2605l's are a great board
    I do run these for an extended period. If this is the case, hadn't had any problems before.
    Is there a work around?
    Would a resistor on the positive of the output of before the motor do anything? Like an EoL situation.
    I don't see the manuf redesigning for me..lol
  • Haha, true they probably won't redesign. Adding a resistor on the output will cause the voltage to be divided between the resistor and your LRA. You should not do this. You could try reducing the rated voltage a little below the specification.. I am not sure how to solve the problem electrically because it sounds like the mechanics of the LRA are degrading..
  • Hi Jim,

    Hope you have resolved this issue. Let us know if we can provide any more assistance. I will close this thread for now.