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LaserPing released - details are here — Parallax Forums

LaserPing released - details are here

Ken GraceyKen Gracey Posts: 7,392
in General Discussion
https://www.parallax.com/product/28041

Let us know what you think of this latest product!

Ken Gracey
«13

Comments

  • GordonMcCombGordonMcComb Posts: 3,366
    Mr. Gracey, please stop coming up with innovative and useful products at attractive prices!

    No, seriously, a drop-in TOF laser light sensor for 30 bucks is very intriguing. Another great addition to the line.
  • VonSzarvasVonSzarvas Posts: 3,450
    edited 2018-02-01 09:46
    OOooh yes!.. like new treats this morning.....

    LaserPING-or-other-treats.png
    LaserPING-or-other-treats.png
    600 x 279 - 469K
  • ajwardajward Posts: 1,130
    edited 2018-02-01 13:59
    That's pretty slick Ken! Added it to my things I need to purchase soon list!

    Amanda
  • rjo__rjo__ Posts: 2,114
    Exactly what I wanted, exactly when I wanted it.

    Now, about those accuracy figures(not that it matters). "1mm" is stated, but further into the docs it is +/- 7% best case.
    ?
  • ercoerco Posts: 20,256
    Love it! I just wish the laser wasn't invisible. I like to see what I'm about to burn. :)
  • RS_JimRS_Jim Posts: 1,764
    Wow!
    A while back, I wrote a PASM program to run 2 pings in a single cog without blocking each other. If any one has 2 of the new laser pings and would try my software, I will dust it off, make revisions necessary for the laser ping and post it here. It is written in PASM with a SPIN interface. Only SPIN requirements are cog launch. Calculations of distance are handled externally so could be done by anything that can access the stored var in hub ram.
    Jim
  • rjo__rjo__ Posts: 2,114
    My compliments to the shipping department... 2hrs to get my package out of the door!!!

  • YanomaniYanomani Posts: 1,524
    Hi erco

    Since the laser ping doesn't need to run continously, you can surround it, perhaps, with three very cheap, low mW, laser diode sources, of different colors, and activate them only when the distance meassurement laser is off, between ping requests.

    Maybe a triangular-shaped setup. with the two horizontal diodes set up to show the direction of the next intended turn (either left or right), and the third one selected when (your next robot???) is going to move straight ahead.

    Sure, the batteries will be drained a little bit more, by having three other power consuming devices onboard, but, since the laser diodes will be also multiplexed you could, at least, control the amount of "wasted" energy.

    Only a thought...

    Henrique
    erco wrote: »
    Love it! I just wish the laser wasn't invisible. I like to see what I'm about to burn. :)

  • ercoerco Posts: 20,256
    I do have some experience adding lasers!

  • Heater.Heater. Posts: 21,230
    Looks brilliant.

    Checks in the post.
  • Don MDon M Posts: 1,652
    Ordered mine today. Will be interested to see how it compares to the Pings I'm using in a project.
  • rjo__rjo__ Posts: 2,114
    Heater. wrote: »
    Looks brilliant.


    idk... looks to me that Erco is following the tracker:) ... and where is the flame thrower?
  • GordonMcCombGordonMcComb Posts: 3,366
    erco wrote: »
    Love it! I just wish the laser wasn't invisible. I like to see what I'm about to burn. :)

    It would be a quick blip, but try an ordinary camcorder or smartphone camera. Most are sensitive to near-infrared light in the region of this device.

  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    I actually had a dream about this device last night. I dreamt that I was working in a group on a room-sized phonograph turntable. (I know: where does this stuff come from?) One of the design requirements was that the tone arm not be allowed to alight on the record if the record were warped. But how to sense a warped record? I told the design team that I knew of just the right sensor for the job!

    -Phil
  • Beau SchwabeBeau Schwabe Posts: 6,566
    Those RFD77402 distance sensors are slick .... I need something like that with a resolution of 100nm over the distance of ten millimeters.

    A comparable item to the RFD77402 is the VL53L0X. Other than they way you communicate to the distance sensor and a slight difference in pinout and a smaller physical size, I'm not sure from a functionality perspective that they are much different.

  • RS_JimRS_Jim Posts: 1,764
    I am confused by the data sheet on the Laser Ping.
    The pulse width is proportional to the distance, and does not significantly change with the ambient temperature, pressure, or humidity.
    To convert the pulse width from time, in μs, to mm, use the following equation:
    Distance (mm) = Pulse Width (ms) × 171.5
    To convert the pulse width from time, in μs, to inches, use the following equation:
    Distance (inches) = Pulse Width (ms) × 6.752
    The text says convert time in us to mm but the formula shows ms, usually a designation for milliseconds. Which is it?
    Jim
  • VonSzarvasVonSzarvas Posts: 3,450
    Good catch Jim. I've just emailed the docs dept at Parallax to refer them to your post.

    Certainly the pulse width will be measured in uS, as that is how ping works.

    Whether the conversion values have been divided by 1000 to present them in mSec, I don't know off hand.

    The conversion is also the same as for ping, if you've got some ping sample code to reference.

    You can literally unplug ping and plug in a laserping and it will work.

    Hope that helps get you going.



  • Hal AlbachHal Albach Posts: 747
    Wow, what fast service! Ordered one on Feb 01 and received it this morning ( Feb 03) via US Mail! Great job, folks!
  • Roy ElthamRoy Eltham Posts: 3,000
    Mine arrived today also!

    Tiny little board, I can fit 3 side by side in the space of one normal ping!
  • RS_JimRS_Jim Posts: 1,764
    VonSzarvas wrote: »
    Good catch Jim. I've just emailed the docs dept at Parallax to refer them to your post.

    Certainly the pulse width will be measured in uS, as that is how ping works.
    Thanks,I am using counters so I can get 2 non blocking distance devices per cog. I was thinking I would need to change multiplier
    Whether the conversion values have been divided by 1000 to present them in mSec, I don't know off hand.

    The conversion is also the same as for ping, if you've got some ping sample code to reference.

    You can literally unplug ping and plug in a laserping and it will work.

    Hope that helps get you going.



    I am using counters and pasm code to get 2 nonblocking pings in a single cog. I was thinking I would have to change constants to go from sound to light.
    Jim
  • VonSzarvasVonSzarvas Posts: 3,450
    The laserping outputs the same protocol, so that light/sound business will be handled internally.

    That said.... what about using a quad-serial cog, and set the laserpings to serial mode?

    Seems to me pwm mode is great for backward compatibility with Ping and for using with slower/older uC's, or existing code/projects. But propeller can do serial no problem, so if your starting new it could be worth considering.

    And you won't need the floating point math either, as the serial value is in millimeters. Assuming you don't want to convert to inches anyway. :)
  • mikeologistmikeologist Posts: 337
    Phil Pilgrim (PhiPi) wrote: »
    I actually had a dream about this device last night. I dreamt that I was working in a group on a room-sized phonograph turntable. (I know: where does this stuff come from?)

    Sounds like a spot of mustard or a bit of underdone potato.
  • RS_JimRS_Jim Posts: 1,764
    VonSzarvas,
    Your 4 laser pings in one cog trumps my 2 per cog! I will let my code die a natural death.
    The data sheet should be up dated though for correctness and prevent future confusion for someone wanting to use pwm.
    Jim
  • ercoerco Posts: 20,256
    Mine also arrived Saturday, just wonderful. Tiny & nearly weightless, this beg to be put on a tiny servo to scan like PING-dar (still one of my all-time favorite projects and an ingenious use of the DEBUG screen for the display). Any good 9g servo is more than up to the task (possibly even a smaller one). I'd like to see Parallax offer a kit with a servo, servo horn/bracket, sensor & cable. In a perfect world, there would be a custom combo 4-wire cable & connector to handle all connections: V+. ground, servo, PING.

    A guy can dream, right?

    @Roy: I suppose you'll be showing us a 10-LaserPing robot soon? :)
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    rjo__ wrote:
    Now, about those accuracy figures(not that it matters). "1mm" is stated, but further into the docs it is +/- 7% best case.
    ?
    1mm is the resolution. +/-7% is the accuracy. Those are two entirely different specs.

    -Phil
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    One thing I am curious about is the refresh rate. The sensor datasheet specs 10 Hz. The Parallax datasheet specs 15 Hz in PWM mode and 22 Hz in serial mode. Either Parallax is wringing more performance out of the chip than it specs, or the module is just sending duplicate data when the sensor hasn't taken a new reading.

    'Still, though, an impressive product!

    -Phil
  • Roy ElthamRoy Eltham Posts: 3,000
    erco,
    I only got 4 of them for now. That 10 ping setup was overkill deluxe.
    The 4 I have are destined for an activity bot base setup.
  • Hal AlbachHal Albach Posts: 747
    edited 2018-02-05 16:47
    Just fired up my new sensor using the Blockly program Ken Gracey showed on his demo video. Works great but I am noticing the output display won't settle on a distance. For example , at say, 23 cm the display will slowly flip 22-23 or 23-24 and sometimes 22-23-24 regardless of the surface and how many tiny position adjustments I make. I'm wondering if that 7% accuracy under cm output is the problem. A little later today I'm going to try it again but change it from cm to inches, hoping that increasing the "window" two and a half times will eliminate the jitter. My plans are for incorporating this little guy into my bot and augment the movable front HC-SR04 sensor.
    Also, mine came with a small 3/8" amber disc stuck to the header. Is this intended to be used with the sensor or is it just something that hitched a ride across the country?

    Update: Switching over to inch mode stabilized the display, no more flipping back and forth.
  • Ken GraceyKen Gracey Posts: 7,392
    Hal Albach wrote: »
    Also, mine came with a small 3/8" amber disc stuck to the header. Is this intended to be used with the sensor or is it just something that hitched a ride across the country?

    I'm not certain, but I think that amber disc is a pick-n-place suction point. I think the headers come from the supplier with this disc exclusively for machine assembly.

    Ken Gracey
  • Hal AlbachHal Albach Posts: 747
    Thank you, Ken! I didn't even think about pick and place features.
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