Wednesday, August 26, 2015

Satellite Data Link Ordered

We will test our 12 foot solar robot boat around Anguilla using cellphone Internet but it really would be fun to try to send this boat across the Atlantic to Africa.  For that we will need some sort of satellite data link.  It would be best to test the sat link early on as well.  So I have looked into it more and ordered one.

At a minimum we want the robot to report its location but we would also like to report more than that.  Things like wave height, tipping angles, current speed, battery level, etc.   Also, if the robot can receive data we could send it new waypoints if it was headed for a storm or something.  We could also decide it was having trouble and should just head home so we can improve things and try again.  It seems much better if we can both send and receive data.

There is Iridium Go that gives you a wifi hotspot with real Internet.  This would work great with our Android phone.   The problem is the device is around $1,000 US and the data service is like $150/month.   This is out of our budget range for something we might send off into the ocean and never see again.

There is Spot which uses GlobalStar.   Spot says they have good coverage for data in the Atlantic.   GlobalStar says they don't have voice coverage off of Africa where we might be headed.    But GlobalStar does say their data coverage is good.   Spot can only send messages and not receive.   There are a number of Spot devices easily found on Amazon including ones that work with a cellphone.   So the big drawback is just that it can not receive.

There is Orbcomm which has sats in LEO (low earth orbit) so a small device can reach them.   We can get service contracts for $17/month and only $7/month when we are not really using it.  We can send and receive data.   It is not realtime as the data may sit on a sat for a bit till it is near a groundstation or our boat but that is fine for us.

I have ordered a Quake Q1000 modem to work with Orbcomm.   It has an RS232 port so I also ordered an RS232 to Bluetooth converter.   With this I think we can send and receive data from our Android phone over satellite.   It was hard to find a retail outlet for these and I ended up finding one on Ebay for about $100 US.

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