Show HN: I built a sonar into my surfboard

Show HN: I built a sonar into my surfboard

code is here

writeup finest seen here

Table of Contents

( yes, I’ve turned the text to the right instructions ever since)

Out browsing, I frequently question how deep the water is, and suspect based upon wave habits that I’m over a deep area or a shallow area. Waves usually break when they get in shallow water (there are different contrasting solutions for determining precisely how shallow). At beach breaks like San Onofre Bluffs, the very best location to await a great wave is right over a sandbar, and the sandbars can move from day to day.

One day I chose to stop questioning and learn. I figured I might construct a depth picking up finder into my board and possibly I ‘d discover a thing or more about the sand beneath me, the characteristics of waves, and perhaps even enhance my browsing. Along the method I likewise discovered some features of my surf board, glue, cordless power, and so on. It was enjoyable and it works so I figured I ‘d share all the information here.

  • Phillips screwdriver
  • Drill
  • Largeish drill bit
  • 1 3/4″ Hole saw (or a little larger I think if you can discover one)
  • Small saw (the one on my Leatherman Wave worked well)
  • Dremel (I utilized the Dremel Lite. It’s quite lame. I miss my plug-in Dremel which I handed out.)


Item Manufacturer Model Source Price Comment
Computer Raspberry Pi 4b I began with the Pi Pico, however updated when I understood: a) The python libraries for the finder would require substantial rework b) It ‘d be rather great to have wifi
Battery system PiSugar S amazon$29
Display Waveshare 2.13 inch_e-Paper_HAT amazon$25 Looks outdoors in the sun. Rather sluggish to revitalize.
Sensor Blue Robotics Ping Sonar (Ping2D) Blue Robotics$279 The variation of this I purchased had potted adapters on both ends, which was a little a discomfort to set up in a board. With mine, I needed to cut a trench in the board to put the cable television therein, and it was a lot longer than required. I figured that was simpler than cutting, soldering and distressing about waterproofing the joint. Ever since they’ve updated the sensor-side port to a WetLink Pentrator– looks method easier. The rate has actually increased a bit, most likely to represent the port.
Serial to USB adapter (FTDI) Blue Robotics BLUART Blue Robotics$42 You might most likely avoid this and utilize a UART on the RPi
Enclosure Polycase WC-21 Polycase$1251
Glue Gorilla Original You desire initial, unclear, for fixing boards. The distinction is initial expands (foams up) when setting and fills readily available area. This is excellent when you wish to “become” the foam.
Surfboard Catch Surf Odysea Log 6′ 0 Catch browse shop here in SC I struggled over which of my boards to utilize and in the end selected the foamie due to the fact that 1) It’s what I ride when the conditions are truly bad which’s when I may have time to take notice of a gizmo. 2) Bad conditions are when I can most utilize the additional aid from a magic sandbar-spotter.
Wireless power receiver HOMEFUNTIME Fast QI Receiver amazon15 Sold in packs of 2 however you just require one. I cut off the external foil layer to make it fit much better and it took 2 attempts to get that right, so I was grateful that I got required into purchasing 2!
Wireless power transmitter TOZO W1 amazon$20
USB cable television CableCreation Micro USB to Micro USB OTG amazon$ 8 I developed something like this by slicing and soldering 2 micro USB cable televisions together (with remarkable heatshrink naturally) and it operated at initially, however then just periodically. I changed to integrating a male micro to female USB-A cable television with a typical USB-A to micro usb cable television. I went through a number of mixes of such cable televisions that looked like they need to deal with no luck prior to discovering one that did. In the end I attempted purchasing this little cable television which has actually been trusted.
Grease Might not be required, however there was a little water inside the enclosure after I evaluated it over night in a bath tub so I included it to the gaskets. No proof of any dripping ever since. I utilized a “single serving” package of bike chain grease that included my Aventon ebike.
Dessicant Aquapapa 2 gram silica gel amazon$ 8.53/ 100
Velcro 3M Any velcro would work great most likely
Mounting tape Scotch108- SML amazon$1653 for a boundless supply
Silicone sealant


Note: I change backward and forward bewtween essential tense (Cut the hole) to very first individual (I cut the hole) in the below. Important is when I’m highly advising doing it my method. Individual is when I feel like there’s an excellent opportunity you might enhance on my approaches!

  1. Set up the RPi. Burn Raspberry Pi OS/ Debian Buster to an sd card. Mount it and develop a wpa_supplicant. conf for your wifi a blank ssh.txt on the boot partition. Solder male headers onto the top of the board if you didn’t purchase 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 display screen onto the headers on the top of the board. At this moment you most likely wish to ssh into the board and have fun with the screen a bit utilizing the python libraries and consisted of examples

  2. Wire it up Link the Ping Sonar to the BLUART board with the consisted of pins, and the BLUART board to the RPi with the male to male usb micro cable television. At this moment you most likely wish to ssh into the board and try the finder utilizing the python libraries and consisted of examples

  3. Set up the code I essentially mashed together among the e-ink examples with among the finder examples. Code is here You most likely desire the code to operate on boot. There are great deals of methods to do this, however I utilized the quick-and-dirty one: include an @reboot line to crontab. Run crontab -e and include a line that goes something like @reboot/ home/pi/surfsonar/ src/sonarDisp. py >/ tmp/sonarOutput. txt 2 > & 1

  4. Box it up Drill a hole in the side of the nontransparent area of the Polycase box for the sensing unit cable television passthrough. Cautious not to drill too near the bottom of package, due to the fact that you require to leave adequate area to screw on the within part of the cable television passthrough. (I made this error and needed to hack away among the installing points on the within bottom of package in order to make it fit). Stick the screen to the transparent front of the case utilizing the installing tape. Stick the cordless power receiver coil there too. You might require to cut it out of its foil product packaging initially (see components area). I utilized glue stay with attempt to glue it to the Polycase however I do not believe that in fact did anything– there was remnant adhesive on the coil PCB which got the job done. It’s a reasonably tight fit so simply think of where whatever goes and experiment with it a bit. Specifically the USB cable television coming out of the RPi– I needed to remove a few of the plastic on the port to make that fit. Close everything up and evaluate it.

  5. Operate
    Prior to you begin butchering, discover the anatomy of your board. In specific, the number of stringers do you have, and where are they? Because you can’t seen them on a foamie, I strolled into the Catch Surf shop and asked. They informed me I have 3 stringers, all quite near the middle. I attempted a stud finder and to my surprise it had the ability to see them.

    Cut a hole in the top of the board simply huge enough for the Polycase box. Drill a hole in the bottom of your board with the hole saw to put the finder in. When you turn the board, bear in mind that the sides change! This sounds apparent, however … ends up it’s a simple error to make (embarrased face). If you utilized a 1 3/4″ hole saw you’ll discover it’s a little small and requires expanding– I hacked away some foam and sculpted away a few of the plastic to expand the circle. I cut a channel in the bottom of the board for the cable television, however didn’t go all the method to the sensing unit hole. For cutting through the plastic on the bottom of the board I utilized a dremel initially and after that utilized my Leatherman Wave saw, cutting at about a 45 deg angle to eliminate a triangular prism of foam with a rectangular shape of slick plastic on top (the “channel cover”). I utilized a drill with huge drill bit to make the connections in between the sensing unit hole, the channel, and the Polycase. I remove enough in the “channel” to fit the excess cable television, and glued the “channel cover” back on. I sealed around the edges of the sensing unit with silicone sealant.

  6. Power Add velcro strips to the charging pad and the top of the Polycase. Now you can keep your board vertical in a board rack and slap the battery charger on it.

    I didn’t include an external power switch of any kind. The PiSugar S has a function where it turns off when the battery comes down to 3V, and changes back on when the battery is credited 3.6 V. It appears to run for 5h approximately on a charge (mindful test pending). My system is typically to connect the battery charger to it the night prior to and let it run all day till the low-voltage detach turns it off. The PiSugar likewise has a function where connecting power ought to switch on the Pi even if it was shutdown typically with high battery voltage. To make it possible for both of these auto-turn-on habits, there’s a confusingly identified switch, identified AUTO on one side and ON on the other. The switch needs to be set on the ON side to allow the automated habits.

I was worried about jeopardizing the watertightness of my board. Someplace on the web I check out a heretic view that foamies do not get waterlogged, which sure would be great, would not it? I figured I ‘d attempt a test. I weighed the foam cylinder I cut on scale that determines to the gram (regrettably I do not have anything much better hand) and got 3g. I soaked it in water under a weight for a number of days and it still weighed 3g. Keep in mind that this is fresh water, not seawater, and I presume the duplicated compression of browsing on it is what in fact drives water into the foam, and I didn’t check that.

I’ve taken it out for one test browse and the numbers were really sensible once I recovered past the break. I paddled out to see and viewed the depth tick up about 2.4 m to 3.2 m, reading 100%self-confidence the majority of the time. Closer to shore, near the breaking waves, I was getting nonsense readings and low self-confidence. I presume this is since the acoustic energy of the breaking waves swamps the ping signal. I require to take a look at the complete waveform information to determine if I can get great numbers in the browse zone. In the interactive plot listed below, you can see the 2 durations where I sat waiting outdoors. The browse was too great to gather more information than that!

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