Search found 1031 matches

by mstrens
Mon Apr 24, 2017 6:03 pm
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

I have no feed back on accuracy but I expect that good results should be achieved when the resistor is selected in order to get about Vcc/2 on arduino pin for the expected temperature. Do not expect an accuracy of 1°C. I think that there are some tolerances on NTC, that the temperature of NTC is not...
by mstrens
Mon Apr 24, 2017 5:35 pm
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

indeed , if you have #define REFERENCE_VOLTAGE 5026 then you should use scale 1000*1023/5026 = 203.54 If #define REFERENCE_VOLTAGE is set as comment, then oXs supposes that Vcc = 5000. If you only measures NTC, in fact the value for reference voltage does not matter because arduino ADC will return t...
by mstrens
Mon Apr 24, 2017 4:39 pm
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

About resistors, the doc says * If no divider is used for some voltage, set both resistors to 0 (zero) and the config #define RESISTOR_TO_GROUND 36 , 20 , 0 , 0 , 0 , 0 // set value to 0 when no divider is used for a voltage; can contains decimals #define RESISTOR_TO_VOLTAGE 670 , 100.1 , 200 , 39 ,...
by mstrens
Mon Apr 24, 2017 3:48 pm
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

jhsa wrote:
Mon Apr 24, 2017 2:45 pm
Also, for sending the temperature to the radio (HUB protocol), do I need to configure a field, or is this one of the default fields??

Thanks

João
Hou need to configure it. There is no default for voltages (and derived measurements)
by mstrens
Mon Apr 24, 2017 3:46 pm
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

In my opinion the voltage offset should also be in the basic config.h file, along with scale voltage. Question, for the NTC, using VOLT_5, shall I set both resistor to voltage and to ground with a value of "0 (zero)?? Thanks João The doc gives already the reply I think * Therefore, in section 6.1 a...
by mstrens
Mon Apr 24, 2017 6:23 am
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

Ok, this is the datasheet of the Thermistor I bought. It is a 3950 with a resistance of 100K at 25ºC. The temperature range is -30ºC to 270ºC, so what temperature must be inserted in the config file? the temperature range I need to measure is around 110 or 120ºC if the engine is not overheating, so...
by mstrens
Mon Apr 24, 2017 6:19 am
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

It is foreseen since a very long time that you can use A6 and A7. If fact you can even use A4 A5 if you do not use an I2C sensor so you could e.g. measure 6 voltages + 1 current (if you do not use an I2C sensor). Here the documentation: * oXs can measure up to 6 input voltages (please note that depe...
by mstrens
Sat Apr 22, 2017 4:57 pm
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

in your config, there is a line #define USE_INTERNAL_REFERENCE // uncomment this line if you use 1.1 volt internal reference instead of Vcc I suggest that you try putting this line as comment. In your case, the voltage on pin 3 (from the current sensor) should be measured compared to Vcc and not to ...
by mstrens
Thu Apr 20, 2017 5:39 pm
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

I think the thermistor will be ok.
100 k seems me a good value when you want yo measure quite high temperatures.
by mstrens
Tue Apr 18, 2017 3:08 pm
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

What do you use to convert capacitor to analog voltage (an electronic board with a 555 ?) Why not trying to use a MPR121. The board is only about 1€5 on aliexpress and it offers much more and is foreseen to measure low capacity. I expect that using an ACC to detect when the model is close to level w...
by mstrens
Tue Apr 18, 2017 10:45 am
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

I put on github a new branch named "test with magnetometer". It is version 8.2.0. It is just a beta version; it means I did not really test it. It contains quite many changes: - oXs_config.h file is now splitted in 2 files oXs_config_basic.h and oXs_config_advanced.h. The idea behind is that in most...
by mstrens
Mon Apr 17, 2017 9:13 am
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

it wil be explained in the config description. Here the draft: // 6.4 - Convert voltage to temperature (° Celcius) ******************************************************************** * In order to measure a temperature it is possible to use special electronic component (like lm35) that generates a ...
by mstrens
Mon Apr 17, 2017 6:47 am
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

I have prepared a new version where you can measure up to 6 NTC (with the same characteristics).
When there is only one or two, you can get the temperature(s).
When there are more than 2, you get the lowest and highest temperature and the index of the highest.

I will put it soon on github
by mstrens
Sat Apr 15, 2017 2:45 pm
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

One option to keep config simple and to reduce the number of data being sent could be to calculate and transmit only one temperature (the max) of several NTC and to consider that each NTC have the same coefficient.
Is this good enough?
by mstrens
Thu Apr 13, 2017 8:20 am
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

Yes, latest version on github support one NTC.
It was just for a test for a member so it is not yet documented in config.h file.
Still it is documented in the ino file. Just do a search on NTC.

Later on I will move the documentation to a better place
by mstrens
Thu Apr 13, 2017 6:04 am
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

Indeed, in current code, only one NTC is supported. Do you need more than one. If so how much? Would be good to have at least 2 (Same as the Frsky RPM sensor), 5 would be awesome for a friend who is running a 5-cylinder radial. I assume the intention is to make them available as config options (ie....
by mstrens
Wed Apr 12, 2017 6:21 pm
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

Indeed, in current code, only one NTC is supported.
Do you need more than one. If so how much?
by mstrens
Wed Apr 12, 2017 3:20 pm
Forum: openTx
Topic: Vibration analysis
Replies: 4
Views: 193

Re: Vibration analysis

GY-521 module has no level converter for I2C bus. I expect this could be an issue for MPU6050 if Arduino is running at 5 Volt and that other I2C sensors with pull up resitors to 5 volt are use. Another point of attention is that I am not sure that current oXs code can run with an IMU6050 without hav...
by mstrens
Wed Apr 12, 2017 8:49 am
Forum: openTx
Topic: Vibration analysis
Replies: 4
Views: 193

Re: Vibration analysis

openXsensor is an opensource project (available on github) that let you connect different kind on sensors to an arduino pro mini. One of the allowed sensor is the GY-86 module that contains accelerometers (MPU6050). Some calculations (to be defined) on the raw values from accelerometers should proba...
by mstrens
Tue Apr 11, 2017 8:14 pm
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

[/quote] Looks like it's locked to a single sensor. Any chance of extending this to additional sensors, or am I missing something? [/quote] It is not clear for me what you mean by "locked to a single sensor". One oXs device replies to some sensor ID's send by the Rx (in fact oXs can send several dat...
by mstrens
Mon Apr 10, 2017 11:21 am
Forum: openTx
Topic: Clarification regarding sensor data and how fast it is read
Replies: 7
Views: 202

Re: Clarification regarding sensor data and how fast it is read

One other member tested it already with openXsensor. He wanted to activate a panic signal on an helicopter when altitude was lower than a defined level. We made a loop between Tx and Rx to measure the time lag from RX to TX and back to RX. I think it could be as low as 200 / 300 msec. I added some c...
by mstrens
Mon Apr 10, 2017 7:03 am
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: Brainstorm: oXs as wing level indication system
Replies: 23
Views: 701

Re: Brainstorm: oXs as wing level indication system

In file oXs_imu.cpp you have pitch.value = 10*atan(gravity.x / sqrt(gravity.y*gravity.y + gravity.z*gravity.z)) * radians_to_degrees; // Pitch in 1/10 of degree roll.value = 10*atan(gravity.y / sqrt(gravity.x*gravity.x + gravity.z*gravity.z)) * radians_to_degrees; // Roll in 1/10 of degree If you re...
by mstrens
Sun Apr 09, 2017 7:23 am
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: Brainstorm: oXs as wing level indication system
Replies: 23
Views: 701

Re: Brainstorm: oXs as wing level indication system

Internally (in oXs) roll and pitch are calculated in 1/10 of degree. oXs send them currently in 1/10 of degree too but as they are put in the fields Acc, I expect that openTx divides the value by 100. So could it be that you get the values in 10 of degree? If so I could make a change in order to mul...
by mstrens
Sat Apr 08, 2017 4:27 pm
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: Brainstorm: oXs as wing level indication system
Replies: 23
Views: 701

Re: Brainstorm: oXs as wing level indication system

Fine that it works.
I will see what I can easily do.
I also think about splitting the config file in 2 parts (basic and advanced).

Did you had a look at the file oXs_config_description.h because normally every thing is explained there.
by mstrens
Sat Apr 08, 2017 7:37 am
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

I made a mistake in previous post. A matrix of 5 * 7 pads can only work when only one pad is active at the same time. In our case, we can only use 12 pads that could be arrange in e.g. 4 * 3 There is a cheap board on aliexpress that should probably work out of the box (need rigth arduino code) if it...
by mstrens
Fri Apr 07, 2017 8:56 pm
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

I had a look at the code. It can't be used in oXs because it uses the CPU for a long time. It should be totally rewritten in order to use arduino timer and perhaps interrupts. I do not think it can be quite reliable. Even if it is once calibrated, I expect that it will drift over time and temperatur...
by mstrens
Fri Apr 07, 2017 6:40 pm
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

jhsa wrote:
Fri Apr 07, 2017 5:48 pm
Yes, but the pressure inside the tank is not always the same.. Depends on the pressurization from the motor, I believe..
As it is a differential pressure, it measures only the difference of pressure between top and button of tank. This is only the height of the liquid
by mstrens
Fri Apr 07, 2017 5:37 pm
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

Another solution could be to use a differential pressure sensor like the MPXV7002DP. This is already supported by oXs. Hmmm, how would you do this? because on glow fuel powered models the fuel tank is most of the times pressured by the exaust gases, so it pushes the fuel to the engine's carburator....
by mstrens
Fri Apr 07, 2017 11:26 am
Forum: OpenXVario - an open source vario supported by the open source firmwares!!
Topic: New beta version of openXsensor (=openXvario)
Replies: 328
Views: 17995

Re: New beta version of openXsensor (=openXvario)

Another solution could be to use a differential pressure sensor like the MPXV7002DP.
This is already supported by oXs.

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