[Dprglist] Compass heading using gyroscopes?

[Doug Paradis]

Murray,
     Benewake has a new LiDAR module called the TF-Luna. It has a range of
between 0.2 to 8 meters and costs about $10 less. It has update frequency
of 100 Hz, and 2 interfaces: 115200 serial, and I2C. It is available from
DFRobot or Amazon. Here is the DFRobot link:
https://www.dfrobot.com/product-1995.html. You also might be interested in
some testing I did on the Benewake TF-mini for outdoors (See:
https://www.youtube.com/watch?v=Mn-_0s5Rb1M).

Regards,
Doug P.


On Sun, May 17, 2020 at 8:46 PM Murray Altheim via DPRGlist <
dprglist at lists.dprg.org> wrote:

> Hi David,
>
> This seemed timely as I was just putting in an order to Mouser for
> a replacement Adafruit 240x240 TFT display (as Adafruit is still
> discouraging ordering from them directly). While rewiring the
> existing one over the weekend I somehow managed to somehow burn it
> out. Grr. I broke a few things this weekend. Sometimes things go
> awry [can you say "tits up" on a public forum?].
>
> I'd originally thought my existing VL53L1X ToF sensor might be able
> to locate a gap at 8' (2.44m) but forgot that its field of view is
> 27°. So no minding the gap there.
>
> My other thought on alignment was to use one of those TFMini wannabe
> LiDARs with an "ideal" range of 12m and a 2.3° "signal acceptance
> angle" (which may be the same thing as field of view, dunno). But
> 2.3° at 8 feet is about 4 inches, which almost seems good enough.
>
> The TFMini is around NZ$80-90 and sucks up 800mA of juice, so it
> wasn't my first choice. By comparison, the chunky Sharp GP2Y0A710K0F
> IR sensor ranges up to 5m, uses only 30mA and is about 2/3 the price.
> They don't mention in the specs its field of view but sure it's
> pretty wide. For a different purpose, understood. And the TFMini
> isn't actually a real LiDAR anyway, just a lens-focused LED. pffft
>
> I like the laser pointer idea better.
>
> I looked and the only laser pointers on Mouser's website are the
> industrial ones (Class 3), the kind that burn holes through whatever
> you're pointing them at -- I could tattoo my cat at 20 feet. I found
> a more suitable one on the NZ equivalent of eBay (TradeMe) that is
> meant to mount on top of a gun (of course). In the advertisement it
> states:
>
>   "Plus, you'll be hitting meaningful targets, like bears and ducks
>    and manly things, as opposed to the pretty little flowers that
>    just happened to be in the way of your poorly aimed shot."
>
> I'm not sure what a meaningful target is, except that there are no
> bears in New Zealand so the guy is plainly either out-of-country or
> out-of-his-mind. But this seems like the right model, runs on three
> AG10 batteries, so either 3.3V or 5V probably would be fine, and it
> comes in tactical black. Very cool and menacing.
>
> This is *iff* I decide to partake in these silly contests. [he says
> as he pulls out his credit card...]
>
> On 18/05/20 12:00 pm, David Anderson via DPRGlist wrote:
> > Murray,
> >
> > Your comment is spot on.  On my SR04 robot there is a calibrated
> > laser pointer for that very purpose; pointing the robot accurately
> > at the first target.   For the experiments with the RCAT robot,
> > the robot itself uses it's sonars to do the alignment, but since
> > in the demo video there are no other waypoints, it's hard to know
> > how effective it is.
> >
> > cheers
> >
> > dpa
> ...........................................................................
> Murray Altheim <murray18 at altheim dot com>                       = =  ===
> http://www.altheim.com/murray/                                     ===
> ===
>                                                                     = =
> ===
>      In the evening
>      The rice leaves in the garden
>      Rustle in the autumn wind
>      That blows through my reed hut.
>             -- Minamoto no Tsunenobu
>
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