Using 1-8S Lipo monitor as a sensor

[offers]

Hi
I like to use "1-8S Lipo Battery voltage monitor alarm" as a sensor.

Is it possible to connect this as a sensor to the openXvario?


I like to use the oXv to measure 3 to 6 cell voltage, and later add current as well



http://www.hobbyking.com/hobbyking/stor ... alarm.html




http://www.r2hobbies.com/rc-1-8s-lipo-b ... alarm.html
I





Offer

[offers]

No body knows? [emoji15]



Offer

[dinamich]

No, it can't be used.

[rihcard]

hi 1st time posting here
So if you use frsky FLVS-01? and connect it in OxS? (for sport protocol)

[mstrens]

hi 1st time posting here
So if you use frsky FLVS-01? and connect it in OxS? (for sport protocol)

FLVS-01 generates digital informations based on the hub protocol.
OXS is not able to read those data and to convert them in SPORT protocol.

OXS makes his own measurements (voltages, current, altitude, climrate, temperature,...) and can send them to Rx based on Hub or on SPORT protocol.

[Kilrah]

So if you use frsky FLVS-01? and connect it in OxS? (for sport protocol)

Just get the SPORT version of the FLVS then (FLVSS or SP-FLVS depending on the seller)

[offers]

I have d8r-ii
Can i use it ad well? How?



Offer

[Kilrah]

If the question is if you can connect that monitor you posted in the first post, no.

[rihcard]

But can i make OxS like a HUB sensor? And connect it through vario meter so that i can brigde it to s.port?

[Kilrah]

There would be no point in doing that. Just use the OXS in smart port mode directly connected to the smart port.

[offers]

If we could, then we could get almost for free,
The connection to balancer plug, the buzzers, display and a led.
I thought it will be cool.

Anyway i am going to build oxs with
current sensor
and 6 cell voltage
This will connect to D8R-ii that will transmit to taranis.

Is there a thread that already show how to handle 6cell?
Since I don't have X8R, will work?



Offer

[mstrens]

If we could, then we could get almost for free,
The connection to balancer plug, the buzzers, display and a led.
I thought it will be cool.

Anyway i am going to build oxs with
current sensor
and 6 cell voltage
This will connect to D8R-ii that will transmit to taranis.

Is there a thread that already show how to handle 6cell?
Since I don't have X8R, will work?



Offer

If you look at
https://code.google.com/p/openxvario/so ... penxsensor
You will find the latest (current) version.
In order to measure 6 voltages and to handel it as 6 cells, you must add 5 or 6 dividers (= 10 or 12 resistors) to an arduino pro mini because the lipo voltages are to high.
Look at the explanations in the file oxs_config.h

Please note that I never used OXS to measure up to 6 cells.
I do not know if someone dit it already.
For 3 cells it is for sure ok but the more cells the less precision you will get.

[offers]

Hi
I make one, with oXs but not very usefull.
The oXs can easily detect 6 cell, but failed to make them reasonably accurate for the voltage monitor.
And the legs of the chip for detecting the current, (15$) just broke.
Its hard to do it reliable when all the resistor / chips are on the air (without board with holes).

[mstrens]

Hi
I make one, with oXs but not very usefull.
The oXs can easily detect 6 cell, but failed to make them reasonably accurate for the voltage monitor.
And the legs of the chip for detecting the current, (15$) just broke.
Its hard to do it reliable when all the resistor / chips are on the air (without board with holes).

The more cells you try to measure, less is the accury on the last cells but the total voltage should be ok. That is because each cell is measured to ground and the voltage of each cell is then calculated by difference. Furthermore, the arduino pro mini has only 10 bit resolution.
Still here some attention points that let you perhaps improve your result.

Did you select your resistors in order to be near the max allowed voltage on each arduino analog pin? Using the same values for all resistors is not optimal.
Perhaps that for the highest voltages, the resistance to ground should be less than 10 k.
Did you calibrate OXS as explained in the config. If you just calculate mv/step based on the theoretical values of the resistors (or even measuring them with an ohmmeter), the precision is not the best you can get. Applying some offset can increase the accuracy in the range you are using.
Do you measure based on Vcc or based on internal reference? When using Vcc, it is important that Vcc is stable (so OXS must be powered via arduino RAW pin with a voltage higher than 5.5 volt in order to let the Arduino voltage regulator regulates correctly.

One way to achieve a better precision would probably be to measure one cells on 2. So for a 6S, OXS would measure 3 voltages only and it would then be possible to let OXS calculate the voltage of each cells considering that cell1 = cell2, cell3 = cell4 and cell5 = cell6. This require some modificaton of the code but this is not difficult. I can do it if required.

I can understand that building an OXS with many resistors without a PCB is quite difficult.
If you are interested, I just made the design for a PCB (in eagle software).
This PCB could be put on top of arduino pro mini (taking care that it supports only one of the many variant of arduino pro mini). It is just about 1 cm longer.
It allows to connect easily (but that are all options):
- 1 or 2 MS5611 (in fact GY63 module) sensors (for altitude and vertical speed uncompensated and/or compensated using a TEK probe)
- 1 4525DO sensor (use to calculated airspeed and compensated vario)
- the cable for PPM (to adjust vario sensitivity (and compensation)
- the cable to SPORT or HUB Rx pin
- up to 8 resistors (in order to measure up to 4 cells)
- a lipo balance connector
- a 3 pin sensor connector (e.g. a current sensor or a temperature sensor). Take care, the sensor is not soldered on the pcb but at the other end of the cable.
- 3 3 pin connector to a RPM sensor. Take care, the sensor is not soldered on the pcb but at the other end of the cable.

With a jumper you can select the way Arduino is powered on:
- directly by Vcc from Rx via PPM or SPORT connector. It avoid using the Arduino voltage regulator (useful when using only 1 lipo)
- via the Arduino voltage regulator and VCC from RX via PPM or SPORT connector
- via the Arduino voltage regulator and Cell3.
If you are interested, I can provide you the Eagle project.
If several people are interested, it could make sense to put a grouped order for this PCB.
Please note that I just finish to work on it. I did not test it.

[jhsa]

- via the Arduino voltage regulator and Cell3.

Why not cell 2 instead f cell 3? Less energy wasted in heat and still well above 5.5V
Ahh, and would allow the use in systems that are powered by a 2 cell LiPo pack..

João

[mstrens]

- via the Arduino voltage regulator and Cell3.

Why not cell 2 instead f cell 3? Less energy wasted in heat and still well above 5.5V
Ahh, and would allow the use in systems that are powered by a 2 cell LiPo pack..

João

Good idea. I changed it already.