This guide is for anyone who has ever rolled over a log to see what lies underneath. What happens when you're not looking? Watch the video above, then dig in (hehe) to this guide and build your own Rhizotron* (SoilCam)!
How does one capture video underground? Waterproof and bury a normal document scanner. Combine a Raspberry Pi Computer and a few amazing software tools to automate the scanning and creation of a time-lapse video!
The Raspberry Pi uses a Linux Operating System (Raspbian), an OS that it and much of the software written for makes automating tasks much easier! If you have never used the Linux OS, or don't feel terribly comfortable with technology fear not! The Pi is designed to make learning easy, you may want to spend some time reading up on the Pi, the terminal, and various linux commands before proceeding. The videos in the following steps are intended for people new to Linux. For those already familiar with, you can probably skim through the pictures.
Like all things in life, you can almost always find help and inspiration with projects like these at your local makerspace / hackerspace!
Cost (Next step covers materials in depth)
$0 - $150, depending on what equipment you need to purchase.
Power & Placement
Where will you setup? If outside, how will you get power/data to it? Check for existing Phone line or Cable access holes. If inside, you can use a large dirt filled pot or 5 gallon bucket located near a power outlet.
The build takes a few hours, but once complete capturing enough data to make longer videos can easily take days, weeks, even months!
Why watch soil?!
Nearly a third of the world's living organisms exist within the soil, and almost none of them have been identified or recorded! It's a huge mystery down there that's full of life, death, procreation, and decomposition. So much of it happens on such a small physical scale and large time scale that capturing it can be difficult. If you've watched the intro video, some of the footage is played back well over 10000x the speed it normally happens!
I would love to see a SoilCam up and running in your yard, beach, bog, tundra, dune, etc. There's a whole world that's almost completely unexplored. Build one, and please share your images and videos!
Click on the next step to start building, or check out http://soilcam.blogspot.com for more footage!
* Rhizotron? What an AWESOME word. "Rhizotron (from Ancient Greek: rhízōma "mass of roots", from rhizóō "cause to strike root") is a laboratory constructed underground in order to study the soil and its interactions with plants and animals" - wikipedia
- $40 Raspberry Pi (Tested with Model B, and Model B 2, 3 should work fine)
- $15 SD Card(Class 10: 16 or 32 GB. Buy with NOOBS loaded to save time)
- $16 Powered USB Hub (Tested with a 4 Port Plugable)
- $10 Ethernet Cable (Tested with Ethernet, WiFi should work fine)
- $25 Scanner (see details below)
- $2 USB Cable for Scanner
- $2 Flathead Screwdriver (Optional, it's only used to pry scanner lid off)
- $10 Aquarium Grade Silicone (No anti-fungal properties)
- $15 Neutral Cure Silicone (optional)
- Plastic Spoon, or something to help smooth out the silicone
- Toothpicks, or something to help get silicone into the cracks
- $1 Rubbing Alcohol
- $1 MicroFiber/Lens/Non Scratching Cloth
- 4 x Clothes-pins (something to use as temporary stand-offs)
- Paper Towels
- Small Shovel (Optional, your hands may work fine)
- Bucket / Pot that can hold the scanner + dirt (IF you're burying this inside)
- Thin sheet of cardboard size of scanner (Cereal box backs work great)
What Scanner to Purchase?
This guide is written for a Canon Lide 20, 110, or 200/210. With a minor modification you can get it working with almost any SANE compatible scanner. See this link for a list of scanners that will likely work, and check the last two pages of this guide for some info on making minor modifications. Please note that of the ~8 scanners I have buried, all died within 6 months (approximately 18,000 scans). Half of them died within a few weeks.
What Scanners to Avoid?
If it's not listed/or incompatible in the prior link you should avoid it.
If it's one of the bigger multi-function scanner/printer/fax/copiers, avoid avoid!
I've avoided non-usb powered scanners due to higher power/voltage concerns.
New or Used? Where to Buy From?
I prefer used, but that comes with a risk of reduced longevity.
Ebay, Craigslist, Amazon, Nextdoor, Freecycle, Family are all great sources.
Silicone, what to get?
Silicone (used in bathrooms/windowsills, not "silicon" as in silicon valley/integrated circuits;) comes in a few different forms. I've primarily used Aquarium Sealant Silicone which does not contain any of the anti-fungal properties that the silicone used in your bathroom does. Fungus plays an important role in nature that we don't want to interfere with. So purchase this if you can! We do use a very tiny amount of Neutral Cure (non-acid curing) silicone for this project, and you can feel comfortable using the Aquarium stuff in its place if you'd rather save the money!