Here is another take on our wearable control tray format, this time with an embedded Win tablet PC that does it all for you. It has the same footprint as our previous trays (e.g. http://diydrones.com/profiles/blogs/fold-up-gcs-with-android-telemetry), but this one has more of a Spartan practicality to it, really.
While this unit was prepared with three built-in RF modules for testing and prototyping purposes, the station framework also works with an external RF box, and in fact with a fully digital link, as well.
Just to be backward compatible with both combined and separate RC/modem solutions, or even a diversity A/V RX, we made room for a maximum of three RF modules inside, and three antennas on top of the controller for short-mid range applications up to a few kms, even without external modules. When using analogue A/V RXs, the video signal is fed through a frame grabber to the tablet with very little latency, so you have a choice of displaying the video downlink either full screen in FPV, or in a window/overlay in your favourite GCS sw when flying auto missions. When using a digital video downlink, you can either opt for the wired LAN port from your external RF box with IP video, or you can just install a ground WLAN bridge for the tablet Wifi inside.
Despite this unit having a PC inside, since most current Android ground station sw packages also support overlaying the direct downlink video on the GUI in various configurations, there's no reason why the very same design wouldn't work with an 8" Android tablet without any serious modifications.
The current IT core:
modified high nit and high contrast 8" PC tablet with either
Intel® Atom™ processor Z3740D/Z3775D
2GB DDR3L-RS, 64GB eMMS
1280x800 IPS display
Intel® Atom x5-Z8500
4GB LPDDR3, 64GB SSD
1920x1200 IPS display
Both original business tablets can sport a built-in HSPA+/LTE modem, but we favour an external USB dongle connected to the front of the tray, because you never know which service provider will have coverage at a particular rural area. Replacing the SIM card in a dongle or the entire USB modem itself is much easier than getting to the SIM slot of the tablet itself...
We have installed a modified OTG USB hub to allow charging the tablet's 20Wh built-in battery on the fly while still linking frame grabber, telemetry modem, 4G dongle, LAN module, etc. to the tablet hw. Depending on charge levels you can power both the tablet and the rest of the control tray hw from the 85Wh or 7500mAh of balanced and protected 3S lipos. This gives you a minimum of 5-8 hours battery endurance for the whole station.
Although this unit contains both an EzUHF LR RC module and an RFD900 modem for compatibility, we can install TBS Crossfire, DragonLink or ULRS for combined RC/TM modem to make it even simpler. Also, while there is a 5.8GHz ImmersionRC UNO AV RX in there right now, depending on your preferred hybrid band plan the AV can still be any of the usual 900MHz/1.2GHz/5.8GHz modules available.
The RC TX logic is our own miniature take on the open source 9x architecture, so you can choose your favourite firmware for both PPM and SBus systems. We are currently running a modified 12ch version of the fw with the EzUHF module, but a 16ch SBus setup is also possible with certain RF modules.
As a personal note, I'm not entirely happy with these separate add-on type labels on the controls, because the colour filled engraving looks way more elegant directly on the main CF board. However, this is an easy way of customising or rearranging the switch functions without having to recut the entire top CF board.
Of course, this belly box model still conforms to our favourite standard compact station format, so a Peli 1400 type enclosure fits it like a glove. We can pack it in the same box with a double field charger, a second telemetry station or with a huge separate compartment for an external RF box, cables, antennas and other accessories.