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Note that actual label for SBUS/PPM pad is "RC".
UPDATED 2018-01-10
There has been a couple of reports that stock R-XSR is not compatible with the hardware UART + diode method.
UPDATED 2017-10-05
The example is now updated with an expected extension to run Camera Control feature over inverted output, and became Version 2.
Not applicable to general public until the inversion option is merged.
Version 2
OMNIBUS F4 Pro Corners configuration example with following setup:
- UART1 : ESC telemetry input (only uses RX1)
- UART3 : SmartPort (inverted, requires an inline diode on TX; mind the diode direction)
- UART6 : SBUS (only uses RX6)
- SOFTSERIAL1 (on TX1) : SmartAudio
- PA9 : Camera control (on TX6)
Version 1
OMNIBUS F4 Pro Corners configuration example with following setup:
- UART1 : ESC telemetry input
- UART3 : SBUS
- UART6 : SmartPort (inverted, requires an inline diode on TX; mind the diode direction)
- SOFTSERIAL1 (on TX1) : SmartAudio
Note that SBUS (UART3) and SmartPort (UART6) can be swapped.
There has been a couple of reports that stock R-XSR is not compatible with the hardware UART + diode method.
UPDATED 2017-10-05
The example is now updated with an expected extension to run Camera Control feature over inverted output, and became Version 2.
Not applicable to general public until the inversion option is merged.
Version 2
OMNIBUS F4 Pro Corners configuration example with following setup:
- UART1 : ESC telemetry input (only uses RX1)
- UART3 : SmartPort (inverted, requires an inline diode on TX; mind the diode direction)
- UART6 : SBUS (only uses RX6)
- SOFTSERIAL1 (on TX1) : SmartAudio
- PA9 : Camera control (on TX6)
Code:
# Betaflight / OMNIBUSF4SD (OBSD) 3.2.0 Oct 5 2017 / 22:44:18 (bbd732be4) MSP API: 1.36 # resources resource SERIAL_TX 1 NONE resource SERIAL_TX 11 A09 resource CAMERA_CONTROL 1 C06 # feature feature SOFTSERIAL feature TELEMETRY feature LED_STRIP feature ESC_SENSOR # serial serial 0 1024 115200 57600 0 115200 serial 2 32 115200 57600 0 115200 serial 5 64 115200 57600 0 115200 serial 30 2048 115200 57600 0 115200 # master set serialrx_provider = SBUS set current_meter = ESC set battery_meter = ESC set tlm_halfduplex = OFF set camera_control_inverted = ON set camera_control_boost = 4
Version 1
OMNIBUS F4 Pro Corners configuration example with following setup:
- UART1 : ESC telemetry input
- UART3 : SBUS
- UART6 : SmartPort (inverted, requires an inline diode on TX; mind the diode direction)
- SOFTSERIAL1 (on TX1) : SmartAudio
Code:
# Betaflight / OMNIBUSF4SD (OBSD) 3.2.0 Aug 28 2017 / 12:02:37 (b2cd7294e) # resources resource SERIAL_TX 1 NONE resource SERIAL_TX 11 A09 resource INVERTER 3 C09 # feature feature SOFTSERIAL feature TELEMETRY feature ESC_SENSOR # serial serial 0 1024 115200 57600 0 115200 serial 2 64 115200 57600 0 115200 serial 5 32 115200 57600 0 115200 serial 30 2048 115200 57600 0 115200 # master set serialrx_provider = SBUS set current_meter = ESC set battery_meter = ADC set tlm_halfduplex = OFF
Warning
I haven't done this myself. Everything is according to theory.
Introduction
There were couples of questions here and there about how an external current sensor can be connected to OMNIBUS F3/F4 Pro Series.
Frankly speaking, using an external current sensor, especially that on a separate PDB, simply invalidates what Pro variants were designed for; simple single board solution. If it is necessary to use the separate PDB with the current sensor, non-Pro variant would provide far more cleaner, easy to build and maintain builds.
However, those of you still want to connect the external current sensor to Pro variants, this blog entry explains how to do it.
Prerequisites
There are couples of prerequisites.
- Understanding of a separate blog entry Understanding Current Meters to know what you are dealing with.
- Proper skill and tools to perform medium fine soldering.
- An external current sensor with voltage output that swings from 0V to 3.3V in proportion to current flowing.
- An ability to self resolve questions regarding specifications and derivatives of the external current sensor, including current rating, schematics, scale to be used.
Directions
The onboard current meter of Pro variants is identical to the typical application circuit for INA169.
And if you are going to use an external sensor, then you will be having an additional circuit just like it.
You task is to isolate the original sensor block and connect the external sensor block to the point where...Continue Reading
I haven't done this myself. Everything is according to theory.
Introduction
There were couples of questions here and there about how an external current sensor can be connected to OMNIBUS F3/F4 Pro Series.
Frankly speaking, using an external current sensor, especially that on a separate PDB, simply invalidates what Pro variants were designed for; simple single board solution. If it is necessary to use the separate PDB with the current sensor, non-Pro variant would provide far more cleaner, easy to build and maintain builds.
However, those of you still want to connect the external current sensor to Pro variants, this blog entry explains how to do it.
Prerequisites
There are couples of prerequisites.
- Understanding of a separate blog entry Understanding Current Meters to know what you are dealing with.
- Proper skill and tools to perform medium fine soldering.
- An external current sensor with voltage output that swings from 0V to 3.3V in proportion to current flowing.
- An ability to self resolve questions regarding specifications and derivatives of the external current sensor, including current rating, schematics, scale to be used.
Directions
The onboard current meter of Pro variants is identical to the typical application circuit for INA169.
And if you are going to use an external sensor, then you will be having an additional circuit just like it.
You task is to isolate the original sensor block and connect the external sensor block to the point where...Continue Reading
Introduction
This is a note for users of OMNIBUS and AIRBOT F4 family those who wishes to isolate ESC_5V rail from rest of the FC so that it could be used to power servos on multi-servo vehicle such as a four control surface airplane.
Background
OMNIBUS and AIRBOT F4 families all share a same design regarding 5V power supply, which is shown below.
The diode triplet is used to select the highest voltage of the three 5V sources, which are ESC_5V, USB_VBUS, and LDO_5V or SBEC_5V. (These diodes also prevents reverse powering unselected sources.)
To power the ESC_5V with an external 5V source dedicated for servo power, one of the diode triplet, Dx, must be removed.
Modding
In theory, you can use a DMM to determine where the Dx is by testing continuity between a relatively large SMD device (marked Dn with diode icon --i>|— in a pin map if you have any) and one of the ESC_5V through-holes/pads. Result of measuring for some of the family members are given below, but builders are advised to verify the continuity before proceeding.
OMNIBUS F3 AIO and F3 Pro
...Continue Reading
This is a note for users of OMNIBUS and AIRBOT F4 family those who wishes to isolate ESC_5V rail from rest of the FC so that it could be used to power servos on multi-servo vehicle such as a four control surface airplane.
Background
OMNIBUS and AIRBOT F4 families all share a same design regarding 5V power supply, which is shown below.
The diode triplet is used to select the highest voltage of the three 5V sources, which are ESC_5V, USB_VBUS, and LDO_5V or SBEC_5V. (These diodes also prevents reverse powering unselected sources.)
To power the ESC_5V with an external 5V source dedicated for servo power, one of the diode triplet, Dx, must be removed.
Modding
In theory, you can use a DMM to determine where the Dx is by testing continuity between a relatively large SMD device (marked Dn with diode icon --i>|— in a pin map if you have any) and one of the ESC_5V through-holes/pads. Result of measuring for some of the family members are given below, but builders are advised to verify the continuity before proceeding.
OMNIBUS F3 AIO and F3 Pro
...Continue Reading
Measure the DC resistance between OUT pin of INA169 and ground.
For the reference, this is OMNIBUS F3 Pro circuit.
For the reference, this is OMNIBUS F3 Pro circuit.
Here are side-by-side comparison pics for two revisions of OMNIBUS F4 Pro boards.
LEFT: OmnibusF4-Pro-0A / OMNIBUS F4 Pro (v2)
RIGHT: OmnibusF4-Pro-0A-V2 / OMNIBUS F4 Pro v3
Note that v3 requires solder jumper to be installed to use the SBUS/PPM pin header.
LEFT: OmnibusF4-Pro-0A / OMNIBUS F4 Pro (v2)
RIGHT: OmnibusF4-Pro-0A-V2 / OMNIBUS F4 Pro v3
Note that v3 requires solder jumper to be installed to use the SBUS/PPM pin header.
Here are the side by side comparison pics between two revisions of non-Pro OMNIBUS F4, with SDCARD.
LEFT: OmnibusF4-0B-V1 (OMNIBUS AIO F4 V2)
RIGHT: OmnibusF4-0B-V3
IMPORTANT
On OmnibusF4-0B-V3 (OMNIBUS AIO F4 V3), SBUS/PPM header is connected to UART6, as oppose to UART1 on F4 V2.
LEFT: OmnibusF4-0B-V1 (OMNIBUS AIO F4 V2)
RIGHT: OmnibusF4-0B-V3
IMPORTANT
On OmnibusF4-0B-V3 (OMNIBUS AIO F4 V3), SBUS/PPM header is connected to UART6, as oppose to UART1 on F4 V2.
Ever dreamed of having one more timer capable pin on your OMNIBUS F3 or F3 Pro, so that you can hook up your TBS SmartAudio or IRC Tramp or S.PORT telemetry?
If you use PPM, then you will have an extra UART
No, that's not what I wanted to tell you.
If you are using S.BUS or other Serial RX receivers, then you can move your receiver input from SBUS/PPM header (J8) to UART3 RX (F3: J22/PWM6, F3 Pro: J12/PWM6), and make the SBUS/PPM header dedicated for PPM signal.
- You may have to re-do your jumper work on SBUS/PPM selection jumpers.
- Newer revision may have solder jumper with SBUS bridged by default. In this case, you have to cut the bridge and install a solder jumper for PPM.
The PPM signal is connected to MCU pin PB4, and you can use this for single-wire software serial available in BF3.1.6 and later.
OMNIBUSF3 / F3 Pro can test if this really works by using the firmware in Exotic OMNIBUS.
If you use PPM, then you will have an extra UART
No, that's not what I wanted to tell you.
If you are using S.BUS or other Serial RX receivers, then you can move your receiver input from SBUS/PPM header (J8) to UART3 RX (F3: J22/PWM6, F3 Pro: J12/PWM6), and make the SBUS/PPM header dedicated for PPM signal.
- You may have to re-do your jumper work on SBUS/PPM selection jumpers.
- Newer revision may have solder jumper with SBUS bridged by default. In this case, you have to cut the bridge and install a solder jumper for PPM.
The PPM signal is connected to MCU pin PB4, and you can use this for single-wire software serial available in BF3.1.6 and later.
OMNIBUSF3 / F3 Pro can test if this really works by using the firmware in Exotic OMNIBUS.
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Figure 1. OMNIBUS F4 SBUS/PPM jumper location. -
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Figure 2. AIRBOT F4 SBUS/PPM jumper location. -
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Figure 3. OMNIBUS F4 SBUS/PPM/UART1 wiring diagram. -
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Figure 4. OMNIBUS F4 PPM (PB14) break out. -
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Figure 5. PPM jumper removed. -
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Figure 6. PPM break out wire soldered. -
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Figure 7. Another end of the break out wire next to the CH2, 5 & 6.
There are numerous articles and video clips that tells you how to calibrate your current meter, but very few if not none, tells you the basics behind the current meter. By understanding the elementary DC circuit level basics, you can eliminate all the guess works and bad calibration results.
INA169: The Current Sensor
There are numbers of different type of current sensor around, but we are going to focus on INA169 based ones, which is most likely the type of sensor you will be dealing with.
Figure.1 shows typical application circuit using the INA169.
What it basically does, is to generate a current flowing out of OUT (pin 1) proportional to voltage difference between Vin+ (pin 3) and Vin- (pin 4). The input voltage difference is caused by load current Is, which we actually want to measure, flowing through a shunt resistor Rs. The output current from OUT will then flow through the load resistor RL and form a voltage Vo against ground.
The Vo is then fed to the ADC converter embedded in an MCU.
The INA169 is designed so that Vo is given by
At this point, we can study the equation (A). Solving (A) for Is we get
INA169: The Current Sensor
There are numbers of different type of current sensor around, but we are going to focus on INA169 based ones, which is most likely the type of sensor you will be dealing with.
Figure.1 shows typical application circuit using the INA169.
What it basically does, is to generate a current flowing out of OUT (pin 1) proportional to voltage difference between Vin+ (pin 3) and Vin- (pin 4). The input voltage difference is caused by load current Is, which we actually want to measure, flowing through a shunt resistor Rs. The output current from OUT will then flow through the load resistor RL and form a voltage Vo against ground.
The Vo is then fed to the ADC converter embedded in an MCU.
The INA169 is designed so that Vo is given by
Vo = Is * Rs * RL / 1000 [V] ...(A)If we are going to connect this output to the CURRENT SENSOR ADC INPUT pin available in many FCs, then Vo should swing between zero and ADC reference voltage for the ADC input pin, which is usually 3.3[V].
At this point, we can study the equation (A). Solving (A) for Is we get
Is = Vo / (Rs * RL / 1000) ...(B)Since maximum value of Vo is 3.3[V], maximum value of Is (Is(max)), the maximum...Continue Reading
