Crius All In One Pro Review

March 18, 2013 15:38 | By | 7 Comments

With MultiWii 2.2 out and advanced features like waypoint navigation becoming really usable on this platform, versatile flight controllers become more and more important. But is the Crius AIO Pro a solid choice, or should you keep your distance? Find out in our review after the break!

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Hardware

When shopping for a MultiWii-compatible controller there is a lot to choose from. In the Atmel-based crowd the Crius AIO Pro stands out with it’s unusual use of mini Molex connectors and the large number of ports. This enables the controller to fit within the standard 50x50mm size that’s supported by most frames. Furthermore, the input pins for the individual channels from the receiver are laid out in a single line.

crius-layout

At first glance, the AIO looks intimidating. The use of mini molex further adds to the intimidation factor – but Crius is supplying a complete set of ready-to-use crimped cables. This means you don’t have to crimp anything yourself, everything you need is contained in the package. But first let’s see what you get with this board:

·ATMega 2560-16AU Microcontroller

·MPU6050 6-axis gyro/accel with Motion Processing Unit

·HMC5883L 3-axis digital magnetometer

·MS5611-01BA03 highprecision altimeter with metal cap

·Supported MegaPirateNG /ArduCopterNG/ArduPlaneNG/MultiWii firmware

·8-axis motor output and 3 servos output for gimbal system

·8 input channels for standard receiver and PPM SUM input channel

·4 serial ports for debug/Bluetooth/OSD/GPS/telemetry module

·8 Analog port for Airspeed Sensor/Current & Voltage Sensor/LED controller

·User-defined pads D32~37 & PG1~PG5

·I2C 5V port for external device

·Output/USB ports provided over current protection

·Reverse polarity protection for input power

·Select jumper for choose internal or external magnetometer

·Onboard 16Mbit Dataflash chip for automatic datalogging

·FT232RQ USB-UART chip and Micro USB receptacle for uploading firmware and debug

·PCA9306DP1 logic level converter for I2C

·Dimension: 50mmX50mmX11.6mm

·Weight: 14.5g

·Fixing hole spacing: 45mm

·Hole diameter: 3.1mm

There are several revisions of this board available, v2.0 features a MS5611-01BA03 highprecision altimeter with metal cap, while v1.0 has a MS5611-01BA01 in a ceramic package. Aside from the package, and a slightly better measurement stability across different supply voltages (2% instead of 2.5%) on the 01BA01, the specifications and performance data in the datasheet are identical. All versions use the MPU6050 chip which provides excellent gyro and accelerometer performance in a single device. The HMC5883L is a well-known magnetometer sensor, and should provide adequate direction sensing performance.

The biggest feature of this board are the four serial ports. Back in the days of MultiWii < 2.0 when everything aside from basic flight was considered a luxury, this seemed like a giant waste. But now it’s 2013, and more and more pilots want not just the bare basics, but also bluethooth / wireless datalink, GPS, OSD and all the other cool toys. There’s also another important factor that makes this board a better choice than, say, a Crius SE: Flash ROM size. With MultiWii 2.2, enabling GPS means the software does not fit into the Atmega 328 of the Crius SE! There are fixes in the MultiWii SVN that bring down the size, and you can get GPS working on the SE, but it’s a tight fit with only about 100 bytes to spare. All this is no issue on the (comparatively) gigantic Atmega 2560. It’s safe to say that this is a trend that’s unlikely to see a reversal. Besides, running a board such as the AIO “barebones” without any GPS or Bluetooth feels like a waste.

The Crius AIO with GPS installed. Note the foam covering the barometric altimeter sensor, which greatly enhances altitude hold precision

The Crius AIO with GPS installed. Note the foam covering the barometric altimeter sensor, which greatly enhances altitude hold precision

The AIO also features analog inputs and a dedicated I2C and FTDI interface. You may be tempted to connect your GPS via I2C but it’s definitely advisable to directly connect that to one of the serial ports for improved navigation performance. Still, it’s great to have yet another interface available for whatever control or measurement task you want to throw at the flight controller.

Last but not least, there’s dedicated camera gimbal outputs and inputs available, as well as a camera trigger output. This turns the AIO into a very comprehensive platform for aerial filming.

Also present right on the board is a micro-USB port. This port is connected to the FTDI chip and you don’t even need to install any drivers on Windows 7 to make this work. Sadly this brings us to the one considerable drawback of the Crius AIO: This USB connector is not designed to be soldered onto a PCB without some form of case keeping it in place. It’s very, very easy to rip off the entire connector. In fact, many sellers advise the use of a bluetooth module to “reduce the wear” on the USB connector. Quite frankly, this is silly – there’s no valid reason why they could not have gone with a more stable connector, or at least one with extra solder points for added stability.

It should also be noted that RCTimer was not willing to exchange our board, instead advising us to use the molex FTDI port instead. This is certainly a workaround, and you can flash your board and do everything via that port – but you need an extra USB FTDI interface for that. This was no issue for us since we got plenty of that stuff around – but a RC hobbyist who just got his Crius AIO board would have to wait another 1-2 weeks for that board to arrive.

 

Performance

This board really shines with MultiWii 2.2 – the sensor array is top-notch, in fact the accelerometer in the Crius AIO is vastly superior to the one used in DJI’s WooKong. This may sound strange considering that the WooKong costs more than 10 times as much as the Crius AIO, but the datasheets don’t lie: for example, DJI uses three individual ADXR620 gyros with a maximum angular sensing range of 300 degrees per second at an output data rate of 2.5kHz, while the sensor used in the Crius AIO can sense up to 2000 degrees per second at a data rate of 8kHz.

It should be noted that such high performance is not necessary for “stable flight” – after all, DJI controllers are well known for their excellent stability, but it’s clear that this stability stems in large parts from software filtering. In fact, stable hover is hardly a real test for the capabilities of a multirotor controller. It’s 3D flight and gusty winds where these boards have to work the most.

Of course the PID values of the MultiWii controller need to be tuned correctly. The procedure for PID tuning is always the same, and has been detailed on the MultiWii wiki. Setting the correct MINTHROTTLE and MAXTHROTTLE  for your ESC in the file config.h is just as important. If your ESCs keep switching off while you descend, chances are your MINTHROTTLE is set too low so your ESC switches off briefly.

Fiddling with the PID parameters. It should be noted that the defaults were usable (though not quite crisp enough) on a 450-size frame.

Fiddling with the PID parameters. It should be noted that the defaults were usable (though not quite crisp enough) on a 450-size frame.

Once the basic setup and tuning is done, flight performance on the AIO is excellent: normal flight feels responsive and deterministic. Best performance is achieved in “Horizon Mode”, which is MultiWii 2.2’s new mode of choice. In this mode, the craft is using 100% autolevel while the sticks are in the center, with autolevel being tuned down more and more the farther you move the sticks to the outer limits. This allows acrobatic flips, followed by an automatic rock-steady hover simply by releasing the controls.

Altitude hold has also been a topic of much discussion. We measured an altitude hold precision of 0.5 meters using a simple foam covering on the barometric sensor. This test was conducted at a large indoor facility, and it was eery to see this kind of performance on a cheap board that costs less than what some manufacturers charge for a cable of their controllers. Of course, the best hardware is nothing without good software, and one has to applaud the MultiWii team for a phenomenal update.

FPVCentral has a dedicated tutorial on getting GPS to run on the Crius AIO. Needless to say, GPS performance depends heavily on the type of module used, so it’s not part of this review.

 

Verdict

The Crius AIO is an excellent choice for everyone who wants to go beyond the feature capabilities of the KK2.0, and pretty much makes the Crius SE and Crius Lite obsolete. With GPS, Bluetooth and camera gimbal output you get the features of a DJI Wookong at a price of around $80.  For $109 you can get a complete set with 900MHz datalink, enabling you to update GPS waypoints beyond the range of Bluetooth. What you have to be willing to bring with you is patience and a willingness to edit a “config.h” file and press the upload-button on the Arduino IDE. It’s an extremely versatile board that offers you choices instead of a fixed set of predetermined (expensive) upgrade options.

Individual pilots swear on the stability of their DJI controllers over everything else. It’s hard to debate such feelings, nor is this the point of this review. What can not be debated however is that while the microcontroller in the AIO is comparatively weak, the sensors are top notch and actually 1-2 generations ahead of the current DJI products.

If you want a board with excellent autoleveling, GPS support as well as plenty of upgrade options and interfaces for other hardware, the Crius AIO is an excellent choice. The only drawback is the flimsy USB interface, so we advise everyone interested in this board to get one of these FTDI USB interfaces just in case.

In the future, we’d love to see a STM32-based board with the same amount of ports and similarly good sensors. But really, it’s hard to fault the AIO at a price of around $60.

Category: Reviews

About the Author ()

FPVCentral is a private, independent news and review site for all things related to First Person View RC model flight. Covering everything from hobby, commercial and military drones, RC models and electronics related to FPV flight, we are not sponsored by any manufacturer or affiliated with any company or project.

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Sites That Link to this Post

  1. IFly4 Quadcopter and Rabbit Flight Controller ARF Set Review : FPV Central | April 2, 2013 13:20
  2. multicopter | Pearltrees | April 2, 2013 23:36
  1. Awesome! I have been looking at a new controller to move forward from the KK, this looks like the perfect option, cheers for the review, there aren’t enough reviews for people like me, who need the low tech explanations 🙂

    • fpvcentral says:

      Thanks for the kind words! Note that while the Crius is still a good board, you can now get an APM Mega Mini from hobbyking for just a little more, and use the very mature ArduPilot software instead of MultiWii and Megapirate.

  2. Matthew Barnard (aka Squidyman) says:

    Thanks for the review! This will confirm my decision on getting AIOP board! I love the versatility of it.

  3. Gene Fedorov says:

    One important issue I would like to see mentioned in this review is the lack of an onboard 3.3 voltage converter, which means Spektrum satellite won’t work with Crius AIO unless powered externally. For such a feature-rich board it is pretty silly not to include one. A dedicated satellite port would be an even better option.

  4. Randy says:

    I love the info on this site…….

    But the tiny white text on black background makes my eyes bleed after a minute of trying to read it.

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