Open-source fish counter updated

fish counter2UPDATE: After meeting with Mike and a whole host of awesome beaver believers at the State of the Beaver Conference, I’ve updated the fish counter design a bit.

To everybody on the Snohomish Pond Leveler crew, here are some of my thoughts for a fish counter on the cheap. As Mike and I found out, what’s currently available is insanely, 5-digit expensive. So the mission is: make it simple, easy to duplicate and hard to break, using readily-available parts. This is back of the envelope stuff, so please feel free to pick it apart and offer feedback in the comments. Oh, and I’m assuming relative familiarity with the basics of a pond leveler here.

The design components are:

  1. 2 jail-broken Iphone 4s or similar, memories empty, inside:
  2. Waterproof cases, which are attached in the remesh with one camera aperture pointing horizontally at the door and another looking down, both with the flash turned on. Plugged into them are:
  3. USB charger cables, waterproofed and routed to the:
  4. Solar power station, with delicate stuff housed in a weather tight box:
    1. 100w panel
    2. 15 amp charge controller
    3. 50AH AGM deep cycle battery
    4. Cigarette lighter adapter
  5. Making it all work is the photo trigger mechanism:
    1. Jail-broken Iphones have a great app called Activator, which can map almost any user action to almost any function on the phone. For example, “one click on headphone switch=take photo or video”. We can emulate this with:
    2. A male headphone jack wired to a waterproof tilt switch which is attached to the door.

Function:

When a fish swims through the door, it tilts the switch. When the switch makes contact, the phones take a photo or video of preset length (3 sec?). Video may require some coding, but would ensure better fish ID—see “additional complexity” below.

Simple—This requires exactly one additional moving part, the tilt switch. With the USB cable running out of the water and over to the bank, you could just plug a laptop in to pull the photos off the phone every few days to do your count. With Wi-Fi turned on in the phone you’d use  more battery power, but could check on the system and pull the photos remotely.

Robust—The example case is waterproof to 30 feet, lead-acid batteries have been around since 1859, the sun will probably rise tomorrow, and Apple stuff’s not terribly buggy. In the worst case of really turbid water, each frame or video capture would be a fish, but of undetermined type. That’d be enough to prove the thing works at least.

Cheap—here’s a sample price sheet:

  1. 2 Iphone 4s, charge cable, etc. SF Craigslist                          $200-250
  2. Solar panel and charge controller, Ebay                               $150-200
  3. 50 AH Deep cycle battery, Interstate                                      $100-150
  4. Alligator clip-cigarette lighter adapter, Amazon                 $8
  5. 2 Optrix XD5 Iphone Action Housings on SF craigslist       $90
  6. Headphone jack from Radio Shack                                         $3
  7. Tilt switch from Radio Shack                                                   $2

Total:            $650ish

Readily available:

Iphones and their trinkets are everywhere, headed to countries with no environmental regulations to be burned for their trace metals. I’m sure there’s also no shortage of Arduino-loving geeks (Maker Faire!) who could whip up a much better system (but I’m not one of them, so please chime in if you are…). Lots of solar panels and whatnot are available used. Etc. etc.

Longevity:

An Iphone needs around 200 ma per hour of talk time, so the battery would provide 5 days of run time to 50% discharge if the solar panel is producing zero. Also, required power should be lower if it’s just sitting there occasionally taking a picture, so hopefully the battery and charger setup will be overkill. 32GB of storage at 2.7MP/photo is around 11,800 photos, so that should be enough for a few days as well.

Want to add additional complexity?

No problem. Kludge up some software to text you when the memory is 75% full so you can come pull photos. Wire in a voltmeter and add more programming so you get a text when the battery is below 50% charge so you can change it out. If the site’s remote and you’re taking video, write a script for Iphoto to automatically import everything a few times a day, and toss a cheap Ipad and 1TB external drive in the box with everything else. For context, 1 TB = 230,400 videos at 3 seconds each in 1280 X 1024 resolution saved as MP4 files. That should just about do it.

If you’re in an area with cell coverage, convince a phone company to donate phones, minutes and data, then set up each individual counter system to call the office and push data to your spreadsheet daily. Get real-time counts without leaving the office. I’d bet there’s a phone company out there that would use this for advertising…

It wouldn’t take much more to integrate these with existing PIT-tag arrays—just add wing fencing that funnels the fish through a counter after the array, and get a count on hatchery vs non-hatchery fish in real time too. Add that data layer to electro-fishing and snorkel surveys.

So, let’s hear your thoughts.