Ok, so where to start?!
First off, YOU GUYS ARE AWESOME! It’s been an incredible few months of rapid iteration and development, largely based on the incredible feedback and contributions from everyone who got their Kickstarter kits. As a community, we're innovating faster than we ever could have imagined.
In case you haven't been tuning into the development calls or following the discussion on the forums, there have been some key updates to the OpenROV that shipped in December. The good news: your ROV is completely upgradeable. Here are the highlights:
Medialink Homeplug Adapters
From the very beginning, we've held onto a dream that we could get very high bandwith communication through a ultra-thin and durable twisted pair tether. Everyone called us crazy. When we found the ETS Baluns (that were included in the kit), we knew we were on the right track. As we discussed in previous updates, even that solution left something to be desired. Ultimately, we wanted something that would communicate at higher bandwidths over longer distances using thinner (and less expensive) wire.
Enter Walt Holm.
Walt shared our desire for a faster connection and began experimenting with Homeplug Adapters. The full story unfolds on the forums here. Bottom line: a specific type of homeplug adapter can be modified to safely communicate at more than 10x the bandwidth of the ETS baluns over great (>100m) distances using almost any pair of wires (and open the door to sending power down the tether as well). It's terribly exciting.
You can order Medialink Homeplug adapters from Amazon. There will be more detailed instructions on how to disassemble and install the homeplugs on the wiki. Don't worry, even if you've already fully assembled your kit, you can still make this upgrade.
Brian Adams got his Kickstarter kit and proceeded to go crazy with updating the code. Last week, we merged all of the changes that Brian has made. You can (and should) upgrade the software on your OpenROV here.
If you'd like to participate in the software development, please feel free to join us for the next development call on Google+. (Here's a call we had about software re-architecture that is a good way to get up to speed. Warning: it's long, sorry about that!) We'd love to hear what you think!
John Stager in upstate New York has been a driving force in development over the past few months. He's been racing ahead of us and solving issues we didn't even know about. Part of his work and feedback has pushed us to find a broader solution to power on board the ROV. After extensive R&D by a number of folks in the community, we're now suggesting that people use rechargeable lithium ion (LiMnNi) batteries to power the ROV. It turns out that typical Alkaline batteries have a relatively high internal resistance, which will cause the ROV to “brown out” (suffer from very low voltages) during operation, but LiMnNi batteries work great. The batteries we suggest are conveniently the same diameter as regular C-cells, but are 1.3 times the length, so three fit where four regular C’s would go.
Note: to use LiMnNi batteries (which have a higher voltage chemistry) the two battery packs must be configured in parallel instead of series. Wiring them this way if you haven’t already built your kit is just as easy as wiring the packs in series and modifying the wiring if you have built the kit is also pretty straightforward.
You can source the same batteries we're using (3 - 2 packs of these, and one charger). But, as always, we encourage you to explore your own solutions and report back to the community.
We're really excited about all of these upgrades, but more importantly, we're thrilled about how these changes happened. We're honored and humbled to be working with you all to create this tool to democratize ocean exploration. It's exciting to think about where this co-creating will lead to next!
As always, don't hesitate to reach out with questions, comments or ideas.
Eric & David