Wishlist for a custom Transmitter board

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14 May 2016 12:30 - 14 May 2016 15:27 #48418 by PhracturedBlue
Wishlist for a custom Transmitter board was created by PhracturedBlue
This came up in the Devo alternative thread, and I think it could be done reasonably cheaply. So..if we were to design a cstom transmitter board that could be used in (almost) any chassis, what would the features be?

Here are my thoughts on what we could add:
  • Smallest possible form-factor for maximum Tx compatibility
  • ARM Cortex (STM32 probably) w/ at least 256kB of space
  • micro-usb/USB-C input/output
  • sd-card
  • as many analog and digital inputs as possible (minimum of 10 Analog inputs, 16 digital inputs)
  • Soft power-switch (like the devo, the switch indicates a desire for power off, it doesn't actually cut the power)
  • Onboard switching power supply (support 1S to 3S battery)
  • USB charging
  • USB programable
  • >=4MB onboard flash
  • header for SPI and 8/16bit parallel displays
  • bluetooth connectivity
  • SPI RF module support with plenty of CSn lines
  • Support for 2nd LCD/OLED display - Is this actually useful?
  • Trainer port
  • support for video streaming
  • audio processor for music/voice (with speaker?)[/quote]
  • vibration motor

And here are some potential issues
  • Switching power-supply may negatively impact the anzlog signaling. We'd need to do some experimentation on this
  • USB charging would probably limit the battery to 1S. And if it was a lipo charging circuit, may specify specific batteries only. Possibly not worth the effort
  • If the SD card were mounted directly on the board, it limits mounting options. so either it is a permanent way to add extra space and would be non-removable, or we just add pads for some external sd-card board
  • Do we actually need onboard Flash if we have an SD card? Is SD-card acess fast enough?
  • Board would not include a display, so we need to ensure that all common displays can be easily wired
  • Board would not include any RF components. They would trigger FCC licensing, and that will likely be out of the scope of this project. The board would likely be designed to have a 4-in-1 bard attached, but would also support other options. this is true for video and bluetooth modules as well.
  • USB has the same issue as the sd-card. Actually adding the plug to the board limits mounting options. Probably need to just have a connector for it.
  • Trainer connectors also come in multiple varieties. again, no socket on board, just a connector
By making this list, it is becoming clear that you aren't getting all that much on the board...Basically it becomes a breakout board for the MCU which isn't much different than existing development boards. We could likely make it much smaller than that, using compact connectors, and include connectors-with-leads to make hookup to the tx easier, but there will be a lot of work involved to actually mount a board like this in any transmitter. The other issue is that we would not be able to provide pre-built images for such a thing. Everyone would configure it differently, and so using the Docker image with some sort of configuration would be necessary. Lastly, debug would be really difficult given the wide-scope of issues users would face from different screen drivers to bad soldering jobs. Support would be a nightmare.

Anyhow, I'm not signing up to build such a board, I just thought it would be an interesting thought experiment.
Last edit: 14 May 2016 15:27 by PhracturedBlue.

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14 May 2016 12:47 - 14 May 2016 12:52 #48422 by stevecox
Replied by stevecox on topic Wishlist for a custom Transmitter board
FWIW other similar ideas now discontinued but some of the ideas, pitfalls could be used - Gruvin9x gruvinandco.com/shop/ and Sky9x openrcforums.com/forum/viewtopic.php?t=1497 and www.ersky9x.net
I actually have a Sky9x board in a 9x and was happy with it until Deviation. If Deviation had a board I wouldn't hesitate to get one. If it would help I would ship the tx anywhere for someone to poke around at.

Hmm from the Gruvin website ...
<Quote>You can still build your own G9X board!
The G9X v4.x boards are fully supported by Open-TX. Full design data (KiCAD) for the final version (v4.2d) is available here.
PCB's can be ordered ecconmically from ITead Studio (or your preferred prototype PCB supplier) by supplying them the Gerber files from within this zip file.</Quote>

Adelaide
Last edit: 14 May 2016 12:52 by stevecox. Reason: addition

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14 May 2016 12:48 #48423 by Deal57
Replied by Deal57 on topic Wishlist for a custom Transmitter board
Does this have the space for a serial TX line for an audio processor, or do we use an ADC and do the audio processing on the CPU? With internal processing I suppose we could use a bluetooth connection to a speaker or headset in addition to an internal speaker. With an audio processor we require limited CPU resources, and may impact on power and space requirements.

Deviation Devo7e 3way switch mod, A7105, NRF24L01
Devo6s 2x2 switch mod, trim mod, haptic, multimodule, A7105, NRF24L01, CC2500
Devo12e 4-in-1 with voice mod -- it speaks!!

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14 May 2016 13:47 #48427 by PhracturedBlue
Replied by PhracturedBlue on topic Wishlist for a custom Transmitter board
Added the audio processor and vibration motor to list. I think it is a good idea.

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14 May 2016 14:28 - 14 May 2016 14:42 #48431 by Cereal_Killer
Replied by Cereal_Killer on topic Wishlist for a custom Transmitter board

PhracturedBlue wrote:

  • Support for 2nd LCD/OLED display - Is this actually useful?

  • After getting my X9E I'd say YES IT'S USEFUL! A second display like an OLED is a great feature (actually it's the reason I ponied up for the E over an X9D)! I only wish the one on my Taranis E was more useful than it already is (OpenTX devs promise it's coming). I wish it would display the model's battery level, currently the only telemetry data it displays is the RSSI (the number value and a pretty little bar graph), the rest of the data is internal transmitter data (tx battery, a useless lifetime counter and a resettable countdown timer).


    My concern is the form factor. Is the idea here to make an AR9X style board that fits perfectly in a transmitter body or will it be a small square (actual shape irreverent) board that could fit in any transmitter? I believe one of the biggest advantages of this system would be the ability to deviate ANY transmitter, even a toy grade RTF packaged tx.Is that kind of where this idea is going?


    Edited to add:
    Here's an idea for the USB connectivity


    This would allow the board to be plugged in directly or a port to be easily wired to the pads (I dont know if you guys have ever used this type of full-size USB connection before but it works fine on it's own and is also easy to solder to).

    Taranis X9E | DEVO 10 | Devo U7E | Taranis Q7

    What I do in real life: rivergoequestrian.com/
    Last edit: 14 May 2016 14:42 by Cereal_Killer.

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    14 May 2016 15:33 #48436 by PhracturedBlue
    Replied by PhracturedBlue on topic Wishlist for a custom Transmitter board
    Updated the 1st post. The idea is to have the board be as small as possible for maximum compatibility.

    I don't like the full-size usb plugs. They go against the USB spec (Type-A is only supposed to be used for master devices), and they require an A-to-A connector which aren't all that common. It also requires a cutout on the board (non-rectangular boards are more expensive in general) though maybe you can get by with a notch on either side. Anyhow, I won't rule it out, but not my preference. It does has the benefit of making initial firmware installation very fast though (assuming no usb plug is on the board itself)

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    14 May 2016 16:01 #48439 by Cereal_Killer
    Replied by Cereal_Killer on topic Wishlist for a custom Transmitter board

    PhracturedBlue wrote: {snip}It does has the benefit of making initial firmware installation very fast though (assuming no usb plug is on the board itself)


    That was my thinking. I like to use boards with those connectors for all my embedded projects, for the initial programming I just plug the entire thing into my computer and then during install I wire a small USB micro port to the easy to access pads with small (30AWG) wire that I can place where ever I want. Super simple and the pinout is impossible to get wrong as it's all straight across (D- to D- and D+ to D+)


    Just an idea, I wont be sad at all if it's not used...

    Taranis X9E | DEVO 10 | Devo U7E | Taranis Q7

    What I do in real life: rivergoequestrian.com/

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    14 May 2016 18:58 #48446 by Flightless Bird
    Replied by Flightless Bird on topic Wishlist for a custom Transmitter board
    My only input on this would be to increase digital inputs from 16 to 32. 16 Digital inputs amounts to only 8 two-position trims, or 4 trims and 8 pushbuttons or switches. This number seems extremely limiting.

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    14 May 2016 19:06 #48447 by Fernandez
    Replied by Fernandez on topic Wishlist for a custom Transmitter board
    For me the CPU board should be future ready, so there should definitively be enough spare ports pins connections memory calculation power plenty of, IO, ADC and more than what you'll now ever can think of. Doing that it means there is always room for creativity and implementation of ideas later.

    Size should be small enough to fit in devo 7e.
    Power not higher than 5V. 3V3 would be best.
    It should be fully modular. No custom pcb needed! Only wiring to be done, to build the TX.
    No need to have all features onboard, but use of standard on the market available modules for, display, RF, wifi,, Bluetooth, GPS, V regulator, sound, buzz, vibr, etc etc,
    Price of the total hardware for the build <50Usd, to attract max of people.

    Doing this leaves room for future development, some may like a big color touchscreen, some other may prefer monochrome small Display, should be possible. Flexibility, to have room for customization changes that's a good thing!

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    14 May 2016 19:17 - 14 May 2016 19:26 #48448 by Fernandez
    Replied by Fernandez on topic Wishlist for a custom Transmitter board
    On extra ideas, not to be implemented by default, but to have just the plenty of io available, or possibly some mux?

    What we could think off out of the box, for later, to have the pins?
    WIFI/Bluetooth
    GPS (for range to model and clock logging sessions etc )
    MEMS IMU
    RF module at least space for 5, many also like to add an UHF LRS module over SPI.
    Outputs: Trainer port, PPM port, and digital port like SBUS.
    Audio module
    Force Feedback
    Last edit: 14 May 2016 19:26 by Fernandez.

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    14 May 2016 22:22 #48462 by HappyHarry
    Replied by HappyHarry on topic Wishlist for a custom Transmitter board
    i think this would be an awesome project, and it would give me something to finally get some good out of my pcm9xii internals again lol. though i think trying to cover many different combo's of parts may be a headache, perhaps settle on a base model and get it working first, then start expanding outwards. ie walking before running :) with that in mind are there any dev boards that fit our bill? or would be looking at a custom board from the get go? unfortunately my coding and electronics skills will limit my input to testing so i'd be fully reliant on others bringing this to fruition

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    14 May 2016 23:32 #48469 by magic_marty
    Replied by magic_marty on topic Wishlist for a custom Transmitter board
    For the average person this will be way to complicated which will limit and eliminate the number of Deviation users..The great thing about porting to a already built and functioning tx is what makes deviation such a great success, making it to where a person will have to build boards ect will kill it...

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    14 May 2016 23:55 #48471 by PhracturedBlue
    Replied by PhracturedBlue on topic Wishlist for a custom Transmitter board
    Deviation will not stop supporting the boards it already supports. This thread is only indirectly related to the question of the future of Deviation. For as long as Walkera Devo Tx are available, that will be the focus of Deviation. After that, hopefully we'll have found an alternative vendor as our 'preferred' transmitter. But there are lots of folks who already have an aging chassis and want to make it usable again, and I think this would be a neat project to enable that. At the moment I don't have any bandwidth to work in it, so it is mostly fantasy, but the discussion may lead to a nice feature-set to implement in the future.

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    15 May 2016 00:39 #48473 by mwm
    Replied by mwm on topic Wishlist for a custom Transmitter board
    +FLightlesBird, you miscounted. 16 digital inputs is 16 two-way switches, as each input is either on or off, not 8, or 8 three or four-way switches (a three-way switches uses two pins, and ignores one of the four possible states).

    The comments about "a dev board" are spot on. Someone has already posted a video to youtube of a proof-of-concept port of deviation to the STM32F429I board. These are relatively cheap - you can get them four around $20, include a (small) touch-screen color LCD, multiple USB ports, all pins broken out except maybe some tied to onboard devices. These are STM32F4 boards, so more CPU than in anything that deviation currently runs on. You can go cheaper and drop the LCD and get a smaller/slower STM32F4, or more expensive for a larger screen, on-board SD cards, audio processors,. They're all roughly the same form factor, which I wouldn't expect to fit in a 7E, and might even have issues fitting in a 10 case.

    The STM32F3 "gumstick" boards should fit in a 7E easily, but you don't get the CPU boost or a complete set of pin breakouts. But they're cheap, costing around $3 in onesies.

    One of the things on my todo list is moving as much of the hardware connections info into hardware.ini as possible. The primary goal is to make it easy for hardware modders to add inputs - the 7E & 6S extra switches, for instance, the "ultimate 7E" extra switches, the guy on rcgroups wanting one 2-way and one 3-way on his 7E, etc., but it should also make setting up a tx based on such dev boards reasonable without having to have a custom build. Supporting those might be a first step towards a custom board like this?

    Do not ask me questions via PM. Ask in the forums, where I'll answer if I can.

    My remotely piloted vehicle ("drone") is a yacht.

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    15 May 2016 07:27 #48478 by Fernandez
    Replied by Fernandez on topic Wishlist for a custom Transmitter board
    If you see how succesfull Arduino became and how many modules boards are available, as long as modules are standard parts can be stacked toghether easily. I think many will follow us, especial RC modellers, who are technical guys who like to build and learn from that. It is part of the hobby.

    The lazy guy, or the sponsored flyer, etc they will never switch to such platform......
    They stick to a nice futaba or buy a Spektrum etc and it works out of the box. Those people anyway will never switch to deviation.

    If modular Deviation Tx become a success, it is not unthinkable some Chinese, will just bring on the market the full deviation board, as you see that with many DIY projects.........For the young generation, I see open source from hardware to source is widely becoming accepted.


    .

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    15 May 2016 20:12 - 15 May 2016 20:17 #48499 by HappyHarry
    Replied by HappyHarry on topic Wishlist for a custom Transmitter board
    the stm32f429i dev board mentioned by mwm seems like a really great candidate 8), the board is ~119mm x 66mm and also has a built in stlink v2. the touch screen is situated off center so if used in a d7e (if it fits) or a d10 chassis the screen will need pulled from it's header and some interlinks made up but that's nothing too difficult to accomplish.

    another alternative is the stm3210e-eval of which the newer version uses an stm32f103zgt6 mcu, which is a 144pin version with 96k of ram and 1mb of flash, it also has support for much the same peripherals as the f4 version like external sd etc too, it is also in the same family of existing devo processors which should make porting to it a little easier I would think?
    Last edit: 15 May 2016 20:17 by HappyHarry.

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    15 May 2016 20:49 #48503 by webbbn
    Replied by webbbn on topic Wishlist for a custom Transmitter board
    This sounds similar to what I was trying to do a couple of years ago. I tore apart some old TXs and built my own interface boards. Mine didn't have LCDs, and were much simpler, but it was fun to experiment with. That said, it's not fun to dig out the old board and resolder all the wires, etc. I don't see this being useful for a large audience. Deviation is what drew me away from building my own control board...

    I just received a couple of STM32F7 discovery boards, and thought that would be a nice board to build a TX around. I wish it was cost effective to build a case with high-quality gimples and switches, etc around that.

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    21 May 2016 22:04 #48984 by Fernandez
    Replied by Fernandez on topic Wishlist for a custom Transmitter board
    Just came across the top model Transmitter from Jr, it is an android controlled Tx. Price 2600usd!!!! OughF www.jramericas.com/234048/JRP01050/?pcat=2

    But the idea could be interesting also for the future deviation, basically use a small ARM development board to connect the hardware Tx modules and all inputs, switches and then use a cheap android tablet or phone as control and display for Tx. There are already chinese models available from 50bucks..... We get then a lot of features directly and can keep the hardware setup more simple.

    Speakers, Mp3
    Vibrator
    GPS
    Touchscreen color
    Bluettooth/Wifi/3G
    Plenty of storage memory for logging etc.

    Only downside is to start your tx, must, boot start the app etc, might take bit longer, complicated, less easy etc.

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    21 May 2016 23:53 #48988 by magic_marty
    Replied by magic_marty on topic Wishlist for a custom Transmitter board
    I remember seeing a video on y-tube were people mounted tablets in the dash of there cars replacing the radio and it worked quite well..There's actually a company that makes custom install kits ..

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    27 May 2016 11:54 - 27 May 2016 11:55 #49362 by Cereal_Killer
    Replied by Cereal_Killer on topic Wishlist for a custom Transmitter board
    OK first, to be clear this IS NOT INTENDED as a solution for this project! This is something I've wanted for a while now and the work by pb, slipstream and HappyHarry have made it now worth it for me to put this together.

    Goal is to build old crappie useless tx's into ultimate 7E's.
    Zif socket for 7e display and flash chip still to be added as well as devo u7e specific labeling in place of stm32 labeling, this is just the first draft (ok that's a lie, this is actually v06 lol)




    Taranis X9E | DEVO 10 | Devo U7E | Taranis Q7

    What I do in real life: rivergoequestrian.com/
    Last edit: 27 May 2016 11:55 by Cereal_Killer.

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