Duct tape, velcro and now blu-tack

I’ve just added blu-tack to my range of adhesive components sticking Phoebe together.

I spotted yesterday Phoebe was showing a 3° nose down tilt when on her horizontal test platform.  That’s a big problem (3°tilt = 0.05g or 0.5ms-2 horizontal acceleration) and it took me a while to find the obvious source – the MPU6050 breakout had shifted in its attachment to the breakboard – probably loosened finally by too many crashes; it has been surprisingly rugged for a very long time.

Hence the blue-tack to keep the MPU6050 breakout firmly attached to the breadboard – although I’m actually using a different black variety which is softer and stickier when massaged.  This means it works itself into nooks and crannies, and then is strong enough to take paint off a wall (it was for sticking my DIY hi-fi speakers to custom stands; it squidged out very thin when putting the two together, and the two were virtually inseparable thereafter).  It also matches Phoebe’s colo(u)r scheme better 🙂

I wonder how much this has been affecting my drift control testing recently?  Weather is good this weekend, so we shall see.

P.S. That’s not my complete set of sticky stuff I use; the last is double-sided padded sticky tape which sticks the Raspberry Pi and breadboard to the frame’s top plate which provided a very strong bond while the padding does provide some noise suppression.  I left it out from the blog’s title as it was too long!

3 thoughts on “Duct tape, velcro and now blu-tack

  1. Since the 3 degree shift of the IMU relative to the frame made a difference, I guess you don’t run the accel cal every time you fly? I run about a second’s worth of cal and store the x,y and z averages every time I arm the motors. Then assuming I always start off on reasonably horizontal ground, the IMU/frame relationship doesn’t matter (as long as it doesn’t waggle!) since I use the cal values as the reference for verticality. Seems to have worked well and vertical takeoff is pretty much perfect now. Your tip on the DLPF really helped that too!

    • Hi Phil,

      As far as I know, it’s not possible to calibrate the accelerometer prior to each flight without using the hidden magic of the MPU6050 motion processor or a completely flat takeoff surface – so I do that indoors like you and store it.

      Pre-flight calibration for outdoors can’t be used – our garden is on an almost imperceptible 3 degree slope (much like the badly seated IMU!) giving 0.5m-2 acceleration which rapidly builds to a very scary, fast, destructive horizontal flight / crash!!!

      Fingers crossed things will now have improved with the blu-tack!

      Andy

      • Ah right – I’ve only ever operated indoors so far, so haven’t come across that issue – I’ve always used a horizontal surface for takeoff. I assume then, that the commercial/open source flight controllers must take the same approach as you if they don’t mandate a horizontal launch pad. Would be interesting to have a nose through them…

        My IMU is now also attached with double sided foam tape and duct tape! For my first attempt I drilled two holes through the base plate and mounted it with plastic standoffs and metal bolts. I knew the base plate distributed power but I thought there’s no way the conductors would run near the centre. On one occasion one of the bolts heated up and the IMU burnt. I had to trash the Lipo as well – there was no way I’d risk using it after such a catastrophic discharge. Oops.

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