oXs Lighter - lights control and more by the oXs

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andrewju
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oXs Lighter - lights control and more by the oXs

Post by andrewju »

Dear All,

I'd like to share the "oXs Lighter" board, designed with great help of Michel (mstrens). The board is targeted to support the new "Sequencer" feature of the oXs that is going to be released shortly (if not already done). One of the most obvious use cases for the Sequencer is aircraft lights control. In a few words, the Sequencer allows for up to 6 outputs to be controlled by Arduino's digital pins (ON/OFF). Up to 9 sequences may be configured on the oXs side utilizing some or all of the 6 output channels. An RX PPM (PWM) stream may be used to switch between configured sequences. There is also a "Default sequence" that gets activated in the absence of RX signal.

The board also offers a voltage divider for oXs to monitor up to 6S LiPo. This allows to utilize the "Alarm" feature of the Sequencer: if a battery voltage drops below some predefined threshold, a certain sequence will be activated by the oXs, thus helping to visualize a low bat situation on your aircraft.

In addition to the above, the board allows installation of an MS5611 sensor (GY-63). In this case you will also get the variometer functionality, which was the main purpose of this sensor some time ago. :)


Note: If you find any errors or inconsistencies in the PCB design - these are definitely mine and Michel has no relation to them. :)


Image

Image



Some specifics of the "oXs Lighter":

Currently the board is designed to accommodate Arduino Pro Mini and GY-63 boards on it. While it may not look as nice and compact as it could have been if all the components were on a single pcb, it's still nice, light weight and relatively easy to assemble.

The sequencer output is controlling FETs which in their turn act as switches. The FETs I suggested in my layout support a load current of up to 2.7A (that's per each channel!) - but your FETs may have slightly different specs. If you're going to use one or several channels with a load as high as 2A, you should take care of cooling as FETs will get very hot. But in the most widespread case of a pulsing (blinking) light the FETs will likely have enough time to cool down and will not require any extra cooling. It all depends on the amount of load applied and specific sequence being used (ON time / OFF time), so it is worth looking after FETs' temperature when you're setting it up for the first time.

The board allows to supply Sequencer Outputs with either the voltage coming from RX (typically 5-6V coming from the model's BEC) or with a voltage from a custom source (the FETs that I used allow up to 55V). There is a dedicated power connector (PWR) and a resistor (R99) that will help you to set the voltage source. In case if you need the "regular" voltage (the one coming from RX), the R99 resistor needs to be installed (it's 0 Ohms, so it acts as a jumper) and the PWR terminal should not be used. In case you need a custom voltage (i.e. 12V for powering sets of LEDs), R99 needs to be removed (so that the custom voltage will not go to the main circuit) and then the custom voltage should be applied to the PWR connector.



Notes on routing and layout:

- The board is designed for SMD components: the FETs come in SOT-223 case and the resistors are 0805 type.
- oXs' PPM input - in fact it's called PWM IN on the board in order to be more precise and bring in additional confusion :) - it is routed to Arduino's pin 2
- Telemetry output - called DATA OUT - is routed to Arduino's pin 4
- LiPo voltage dividers are routed to pins A0, A1, A2, A3, A6 and A7
- MS5611 sensor is connected to pins A4 and A5, and is powered from VCC line of the Arduino
- The Pro Mini's programming header is left free, so Arduino could easily be programmed by an FTDI RS232 adapter (just as described in the Wiki)


The size of the board is about 26x52mm (1x2 inches). The total weight of a fully equipped board (including the Pro Mini, GY-63, 6 FETs for the Sequencer and 6 dividers for LiPo monitoring) is about 15 grams (0.5oz) excluding wires, connectors and shrink tube.


I am currently testing some boards (based on an earlier layout design, so the ones proposed here should be even better):

Image

Image

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So far they work just as expected.


You can get the layout of the latest version here (rev.02a). The files are made in Eagle 6.6.


As usual, there is probably some room for improvement.
So your questions, comments or suggestions are very welcome! :)



P.S. The LEDs I planned to use for my aircraft are 1W or 3W high-power LEDs like these. They also come in different colors (Red / Green / Blue / White). During my tests I power them directly with the BEC voltage (5.5V) and make them light up for 20-50ms every second. This way they do not consume much power and remain cold. And they are really very bright - it even hurts your eyes!



P.P.S. Don't forget to cover the MS5611 side with something dark (non-transparent) as the barometric pressure sensor is light-sensitive!

kabturek
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Re: oXs Lighter - lights control and more by the oXs

Post by kabturek »

Great stuff, thanks! i'll edit the eagle file and add a current sensor (max 5s then)
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jhsa
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Re: oXs Lighter - lights control and more by the oXs

Post by jhsa »

Nice.. Sequences are hardcoded in the arduino, right?
And then you select them with different channel values?

João
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andrewju
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Re: oXs Lighter - lights control and more by the oXs

Post by andrewju »

kabturek,
I think I updated my design after I posted this version... Let me know if you need my latest files.

João,
Sequences are set up in oXs - so it's fully user-configurable. :)
And yes, you can select them with different channel values. Plus, there's a special "alarm" sequence that will be activated when battery voltage drops below some threshold (if battery voltage monitoring is configured in oXs).
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jhsa
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Re: oXs Lighter - lights control and more by the oXs

Post by jhsa »

Cool ;)
Thanks

João
My er9x/Ersky9x/eepskye Video Tutorials
https://www.youtube.com/playlist?list=PL5uJhoD7sAKidZmkhMpYpp_qcuIqJXhb9

Donate to Er9x/Ersky9x:
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