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General suggestions or questions about the SparkFun Electronics website
By jumpshot44
#192867
Hello - need some guidance/participation on an exciting project.

We are building a 21st Century Message in a Bottle (or flat case if necessary) as a community project on devRant.io. We are 20,000+ software developers but fairly new inexperienced Makers.

The drifter will be put in the Gulf Stream off Cape Hatteras late March 2017. The goal, if we are fortunate, is Europe. We are building apps and desktop environment to track the vessel. That is the easy part for us. We will be sharing any code we create.

We will either use a 1 Gallon clear plastic PET bottle with a 4.5" opening or if necessary flatter surface container that we can easily get wider specifications. Whichever, must be airtight and waterproof. We are in the midst of testing options right now.

Thinking of using:
Arduino or Rasberry PI Zero
Iridium RockBlock, Stingr or alternative to track the vessel.
Charger
Battery
GPS
Solar cell - 6v/2w
Possibly an Accelerometer

Has anyone in the forum done this? Do you have advice you can share? We also have a Slack where we share info and testing videos.

Thanks,
Marty
jumpshot44@gmail.com
By theropod
#192882
I would increase your solar capacity by a factor of two. No cell lives up to its rating, and there will be other losses. A little more is always better than not enough. When the batteries age a little and storms hinder charging that extra solar will be welcome. I would also consider a wave assisted generator hung underneath which would help keep the craft stable as it would act as a balast. Keeping those panels pointed up would be nice. Good luck!

RS
By jumpshot44
#193965
Thank you. We are increasing the solar capacity by a factor of two. Do you know if the Iridium Rockblock antenna will work through clear plastic? We would rather not put it outside the bottle as more vulnerable to water leakage.

Also, I am trying to find the wave assisted generator. Do you know where I can get one?

Thank you,
Marty
devRant.io
By jremington
#193969
Do you know if the Iridium Rockblock antenna will work through clear plastic?
That is extremely easy for you to test.

You won't find an off the shelf "wave generator".

Any technology you put in that bottle must be thoroughly tested under rough conditions before launch, or you are just wasting your time and effort.
By theropod
#193998
jumpshot44 wrote:Thank you. We are increasing the solar capacity by a factor of two. Do you know if the Iridium Rockblock antenna will work through clear plastic? We would rather not put it outside the bottle as more vulnerable to water leakage.

Also, I am trying to find the wave assisted generator. Do you know where I can get one?

Thank you,
Marty
devRant.io
There might be a couple ways to implement a wave motion activated/driven generator. A fixed coil with a spring suspended magnet where the up and down motion of waves forces interaction. This would require a guide, or keeper, where the magnet is constrained to a specific path. Look at the shake powered flashlights. Another method might be a magnet inside a curved tube where the back and forth tilting of the bottle causes the magnet to pass a coil. With this method a coil on each side of this curved path could be used. In either case this will require a rectification method, and both the solar cell and generator will need a charge controller so as to not over charge your battery. A long duration storm could output power for days. A real problem will be matching voltage and amperage output of said generator to your battery. "Wild" output from this, like a wind turbine, will produce spikes far above what the battery can safely accept. I still feel that a solar panel larger than needed will suffice as such a panel will provide power on cloudy days. You are basically doing what the probes to Mars are doing, but we are much closer to the sun, and dust will not be an issue. Algae growth just might be a problem. Good luck!

RS