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

or

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.
 

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Comment by Nicholas Witham on January 12, 2017 at 4:45pm

Looks great! Out of interest, what type of Radio Control protocol are you using, and how are you generating it?

I have built something similar (but no where nearly as refined as yours). Im using a Teensy3.2 to convert the pots/switches/gimbals to a PPM stream (soon to switch to SBUS), then a DTFUHF 1W Tx/Rx to transmit that signal.

Im also using an RFD900+ modem connected by USB to the built-in tablet to send/receive telemetry and commands.

I really like the way you have labelled your switches, and will likely borrow that idea.

Comment by Azjeg on January 12, 2017 at 5:16pm

Thanks Nicholas! We have developed our own tiny version of the now open source 9x TX logic, which has a number of different 3rd party fw forks to work with, so there's a full function RC built in there. We have several different versions of basically the same hw, the smallest being the size of my thumbnail, so we can embed it in even the smallest controllers.

The labels are engraved with our 60k rpm CNC end mill using a 45°-60° pointy router bit, colour filled with a paint marker then the excess wiped off with acetone. We use the same method in small series production batches, it's fast and it's also very durable.

Comment by Nicholas Witham on January 12, 2017 at 5:59pm

Wow, that's awesome! Do you sell those boards separately?

Im still developing mine, but at the moment I have no way of changing any of my settings without manually changing and re-uploading the code. I hope to one day use a bluetooth connection from the teensy to a tablet where an app can change the settings. I'd love to be able to have something like OpenTx do this, whether it be on a teensy or another board.

Comment by Pritam Ghanghas on January 13, 2017 at 1:43am

Looks very professional. Those sticks look nice where did you get those, I couldn't find good sticks when I was doing something like this on raspberry pi.

Comment by Azjeg on January 13, 2017 at 4:31am

Nicholas, we don't sell them as a separate item, because we would have to provide a huge amount of documentation and support with it. It's also a really tiny SMD board, which fits our own in-house assembly processes, but not exactly DIY friendly. We make a slightly larger one with the original JST headers for these Peli 1400 size trays, and a 1.27mm spaced PicoBlade header type is also in the works for tighter integration. PM me if you'll be interested in that one. Until then you can still buy a bog standard Turnigy 9x for peanuts and use the main board if it fits into your assembly.

Comment by Azjeg on January 13, 2017 at 4:52am

Pritam, these were originally available as "Rotorworkz Stick Bling" for both 3mm and 4mm joystick shafts, but they've disappeared a few years ago. Now we turn our own on a lathe and have them hard anodised.

Comment by Adam Kelly on February 26, 2017 at 11:10pm

I'm interested in having something similar built for a concept demonstrator we are working on. Could you message me to talk about price, specs etc?

Comment by Azjeg on February 27, 2017 at 3:42am

Adam, I just sent you a PM.

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