Low-cost Drift Buoy Plies the Atlantic for Nearly a Year

Put a message in a bottle and toss it in the ocean, and if you’re very lucky, years later you might get a response. Drop a floating Arduino-fied buoy into the ocean and if you’ve engineered it well, it may send data back to you for even longer.

At least that’s what [Wayne] has learned since his MDBuoyProject went live with the launching of a DIY drift buoy last year. The BOM for the buoy reads like a page from the Adafruit website: Arduino Trinket, an RTC, GPS module, Iridium satellite modem, sensors, and a solar panel. Everything lives in a clear plastic dry box along with a can of desiccant and a LiPo battery.

The solar panel has a view through the case lid, and the buoy is kept upright by a long PVC boom on the bottom of the case. Two versions have been built and launched so far; alas, the Pacific buoy was lost shortly after it was launched. But the Atlantic buoy picked up the Gulf Stream and has been drifting slowly toward Europe since last summer, sending back telemetry. A future version aims to incorporate an Automatic Identification System (AIS) receiver, presumably to report the signals of AIS transponders on nearby ships as they pass.

We like the attention to detail as well as the low cost of this build. It’s a project that’s well within reach of a STEM program, akin to the many high-altitude DIY balloon projects we’ve featured before.

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Hackaday Prize Entry: SunLeaf

If there’s one place where the Internet of Things makes sense, it’s agriculture. From vast fields of soybeans, corn, and a different variety of corn, to the backyard garden, knowing how much sun, and rain crops get can vastly increase yields. For their Hackaday Prize project, [Adam] and [Shane] are building  a board designed explicitly for plants. It’s called the SunLeaf, and it has all the sensors and radios a good remote sensing board needs.

The SunLeaf is built around an ARM Cortex M4 microcontroller with an ESP8266 module for WiFi connectivity. Sensors are important for any remote sensing board, and for this the guys are going with SeeedStudio Grove connectors, providing four UARTs, four I2C, and four analog ports.For remote sensing applications, you generally can’t rely on mains power, so SunLeaf includes a port for a solar panel and a battery charger.

Although this project was originally a redesign of [Adam] and [Shane]’s Hackaday Prize entry from last year, what they’ve come up with is a great device for data logging, autonomous control, and environmental sensing for anything, from farms to weather stations.

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Simple robot knows its bounds

table_top_bot

The [Dallas Personal Robotics Group] recently put together a set of tutorials for their members, including the build process of a table-top robot, they call the Tiny Wanderer. The bot can be constructed pretty easily, and is meant as an introduction to robot building.

The small servo-driven bot uses simple edge sensors to ensure that it doesn’t fall off a raised surface. The sensors were built using a small IR LED and photo transistor, which is partially isolated from the LED by a piece of shrink tubing. An ATiny micro-controller takes two measurements of the amount of IR light entering the photo transistor – one with the LED on, the other with the LED off. The difference of these measurements is compared to determine if the edge sensors are hanging off the side of the table. The logic used here is pretty simple – the difference will be high if the sensors are hovering over a surface, due to reflected light, and low if the sensors are hanging over open space.

The writeup contains templates for building the bot’s structure, as well as source code and schematics for all of the electronic bits.

Be sure to stick around to see a video of the robot in action.

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