Hide HN: I constructed a sonar into my surfboard

code is here

writeup most effective viewed here

Table of Contents

(yes, I’ve rotated the textual squawk to the correct route since then)

Out surfing, I most incessantly wonder how deep the water is, and suspect in step with wave conduct that I’m over a deep put or a shallow put. Waves normally fracture when they enter shallow water (there are diverse conflicting formulas for understanding precisely how shallow). At seaside breaks esteem San Onofre Bluffs, the finest space to seem forward to a horny wave is suitable over a sandbar, and the sandbars can switch round from day after day.

At some point I sure to end questioning and rep out. I figured I would maybe perchance make a depth sensing sonar into my board and maybe I’d be taught an aspect or two about the sand under me, the dynamics of waves, and even maybe give a improve to my surfing. Along the formula I additionally realized some issues about my surfboard, glue, wi-fi energy, and so on. It was once fun and it works so I figured I’d share the total main gains here.

  • Phillips screwdriver
  • Drill
  • Largeish drill bit
  • 1 3/4” Hole noticed (or a minute bit better I bet in case you would maybe perchance maybe rep one)
  • Small noticed (the one on my Leatherman Wave worked properly)
  • Dremel (I feeble the Dremel Lite. It’s rather lame. I miss my sail-in Dremel which I gave away.)


Item Manufacturer Model Provide Impress Comment
Computer Raspberry Pi 4b     I began with the Pi Pico, however upgraded when I noticed: a) The python libraries for the sonar would need main rework b) It’d be slightly good to contain wifi
Battery machine PiSugar S amazon $29  
Hide Waveshare 2.13inch_e-Paper_HAT amazon $25 Seems to be expansive beginning air in the sun. Rather slack to refresh.
Sensor Blue Robotics Ping Sonar (Ping2D) Blue Robotics $279 The model of this I supplied had potted connectors on each ends, which was once slightly of a grief to put in in a board. With mine, I needed to reduce a trench in the board to position the cable in there, and it was once unprecedented longer than mandatory. I figured that was yet again uncomplicated than slicing, soldering and annoying about waterproofing the joint. Since then they’ve upgraded the sensor-facet connector to a WetLink Pentrator – looks to be formula more convenient. The cost has long gone up slightly, presumably to story for the connector.
Serial to USB adapter (FTDI) Blue Robotics BLUART Blue Robotics $42 You should perchance potentially skip this and employ a UART on the RPi
Enclosure Polycase WC-21 Polycase $12.51  
Glue Gorilla Fashioned     You would favor long-established, no longer determined, for repairing boards. The incompatibility is long-established expands (foams up) when setting and fills on hand home. Right here’s beautiful whenever it’s fundamental to “grow into” the foam.
Surfboard Prefer Surf Odysea Log 6’0 Prefer surf store here in SC   I agonized over which of my boards to employ and in the end made up our minds on the foamie because 1) It’s what I lumber when the stipulations are truly unpleasant and that’s when I would need time to hear to a machine. 2) Noxious stipulations are when I will most employ the extra encourage from a magic sandbar-spotter.
Wireless energy receiver HOMEFUNTIME Like a flash QI Receiver amazon 15 Offered in packs of two however you most effective need one. On the replacement hand, I reduce off the outer foil layer to produce it fit better and it took two tries to glean that appropriate, so I used to be once gratified that I got compelled into procuring for 2!
Wireless energy transmitter TOZO W1 amazon $20  
USB cable CableCreation Micro USB to Micro USB OTG amazon $8 I created something esteem this by cutting and soldering two micro USB cables together (with impeccable heatshrink obviously) and it worked in the beginning, however then most effective intermittently. I switched to combining a male micro to female USB-A cable with a typical USB-A to micro usb cable. I went thru plenty of combos of such cables that regarded esteem they ought to work with no success old to finding one which did. Within the end I attempted procuring for this minute cable which has been reliable.
Grease         May maybe perchance well perchance no longer be mandatory, however there was once slightly of water inside the enclosure after I tested it in a single day in a bathe so I added it to the gaskets. No proof of any leaking since then. I feeble a “single serving” packet of motorcycle chain grease that came with my Aventon ebike.
Dessicant Aquapapa 2 gram silica gel amazon $8.53 / 100  
Velcro 3M       Any velcro would work dazzling potentially
Mounting tape Scotch 108-SML amazon $16.53 for an infinite present  
Silicone sealant          


Hide: I switch bewtween crucial stressful (Minimize the opening) to first person (I reduce the opening) in the under. Imperative is when I’m strongly recommending doing it my formula. First person is when I truly feel esteem there’s a horny probability you would maybe perchance maybe give a improve to on my solutions!

  1. Problem up the RPi. Burn Raspberry Pi OS / Debian Buster to an sd card. Mount it and make a wpa_supplicant.conf for your wifi a blank ssh.txt on the boot partition. Solder male headers onto the head of the board in case you didn’t favor the pi with headers. Screw the PiSugar onto the bottom of the board (so the pogo pins contact solder joints on the bottom of the board). Press the express onto the headers on the head of the board. At this point you potentially must ssh into the board and play with the express slightly the usage of the python libraries and integrated examples.

  2. Wire it up. Join the Ping Sonar to the BLUART board with the integrated pins, and the BLUART board to the RPi with the male to male usb micro cable. At this point you potentially must ssh into the board and strive out the sonar the usage of the python libraries and integrated examples.

  3. Problem up the code. I essentially mashed together in actual fact some of the e-ink examples with in actual fact some of the sonar examples. Code is here. You potentially need the code to bustle on boot. There are varied ways to produce this, however I feeble the quick-and-soiled one: add an @reboot line to crontab. Stride crontab -e and add a line that goes something esteem @reboot /house/pi/surfsonar/src/sonarDisp.py > /tmp/sonarOutput.txt 2>&1.

  4. Field it up. Drill a hole in the facet of the opaque share of the Polycase field for the sensor cable passthrough. Cautious now to not drill too end to the bottom of the sector, since you contain to lumber away ample home to screw on the inside share of the cable passthrough. (I made this error and needed to hack away in actual fact some of the mounting gains on the inside bottom of the sector in suppose to produce it fit). Stick the express to the clear front of the case the usage of the mounting tape. Stick the wi-fi energy receiver coil there too. You should perchance must reduce it out of its foil packaging first (view substances share). I feeble glue persist with envision up on to glue it to the Polycase however I don’t stutter that in actual fact did the rest – there was once remnant adhesive on the coil PCB and that did the job. It’s a moderately tight fit so true take into story where every thing goes and mess round with it slightly. Specifically the USB cable coming out of the RPi – I needed to reduce away some of the plastic on the connector to produce that fit. Shut all of it up and test it.

  5. Feature.
    Earlier than you originate up butchering, be taught the anatomy of your board. In specific, what number of stringers produce you’ve got, and where are they? Attributable to that you just can’t considered them on a foamie, I walked into the Prefer Surf store and asked. They told me I truly contain three stringers, all rather end to the center. I attempted a stud finder and to my surprise it was once in a role to view them.

    Minimize a hole in the head of the board true colossal ample for the Polycase field. Drill a hole in the bottom of your board with the opening noticed to position the sonar in. As soon as you occur to flip the board, undergo in thoughts that the perimeters switch! This sounds glaring, however… turns out it’s a straightforward mistake to produce (embarrased face). As soon as you feeble a 1 3/4” hole noticed you’ll rep it’s slightly of limited and wants enlarging – I hacked away some foam and carved away some of the plastic to amplify the circle. I reduce a channel in the bottom of the board for the cable, however didn’t lumber the total formula to the sensor hole. For slicing thru the plastic on the bottom of the board I feeble a dremel in the beginning after which feeble my Leatherman Wave noticed, slicing at a pair of 45 deg perspective to recall away a triangular prism of foam with a rectangle of slick plastic on high (the “channel lid”). Then I feeble a drill with colossal drill bit to produce the connections between the sensor hole, the channel, and the Polycase. I reduce away ample in the “channel” to fit the excess cable, and glued the “channel lid” again on. I sealed round the perimeters of the sensor with silicone sealant.

  6. Vitality Add velcro strips to the charging pad and the head of the Polycase. Now that you just can preserve your board vertical in a board rack and slap the charger on it.

    I didn’t add an external energy switch of any kind. The PiSugar S has a feature where it switches off when the battery gets down to 3V, and switches again on when the battery is charged to a pair of.6V. It looks to bustle for 5h or so on a charge (careful test pending). So, my machine is incessantly to connect the charger to it the evening old to and let it bustle all day till the low-voltage disconnect turns it off. The PiSugar additionally has a feature where attaching energy ought to flip on the Pi despite the indisputable fact that it was once shutdown normally with excessive battery voltage. To enable each of these auto-flip-on behaviors, there’s a confusingly labelled switch, labelled AUTO on one facet and ON on the more than just a few. The switch ought to be set on the ON facet to enable the automated behaviors.

I used to be once though-provoking on compromising the watertightness of my board. Someplace on the rating I be taught a heretic stare that foamies don’t glean waterlogged, which sure will likely be good, wouldn’t it? I figured I’d strive a test. I weighed the foam cylinder I reduce on scale that measures to the gram (sadly I don’t contain the rest better hand) and got 3g. I soaked it in water below a weight for a pair of days and it level-headed weighed 3g. Hide that here’s original water, no longer salt water, and I believe the repeated compression of surfing on it’s miles what truly drives water into the foam, and I didn’t test that.

I’ve taken it out for one test surf and the numbers were particularly life like after I got successfully previous the fracture. I paddled out to view and watched the depth tick up about 2.4m to a pair of.2m, studying 100% self perception as a rule. On the replacement hand, nearer to shore, advance the breaking waves, I used to be once getting nonsense readings and low self perception. I believe here’s since the acoustic vitality of the breaking waves swamps the ping signal. I contain to peek at the corpulent waveform data to figure out if I will glean beautiful numbers in the surf zone. Within the interactive put under, that you just can view the two sessions where I sat ready beginning air. The surf was once too beautiful to bag more data than that!

Content Protection by DMCA.com

Back to top button