Hobbyking i86 / Eagle N6 Multi-Rotor Control Board Review

June 7, 2012 22:34 | By | 10 Comments

At a mere $20, the Hobbyking i86 is a cheap clone of the Eagle N6 V1 board. Unlike KK, MultiWii and most other boards it does not require the user to flash a firmware in order to fly, instead the airframe type can be set via DIP switches. It’s simple, it’s cheap and it’s small, but is it worth saving money on the controller board?

The i86 / Eagle N6 controller is one of the most compact boards on the market

The first noticeable thing is the size of the board. It’s tiny, only 40x40mm, weighing just 8 grams! At that size it’s feasible to put this board into a small foamie plane as stabilizer. The board has a nice quality feel to it, the soldering is top notch and the multilayer PCB really feels solid. This is not a board that will break easily. Servo output is clocked at 400 Hz, which can pose a problem with low-speed ESCs, so make sure you get  an ESC that supports a high update rate. Turnigy Plush are usually a solid bet, but HobbyWing ESCs seem to work fine too. Supported input voltage ranges from 4V to 6V.

The i86 board installed in a 450-size quad frame

Much like the KK board, there are three pots for changing sensitivity (as well as some basic setup, which we’ll get to later) – a telltale sign that the i86 board is based solely on a gyro. The gyro sensor used here is an integrated STM 3-axis MEMS type, sitting smack in the middle of the PCB. Aside from connectors for up to 6 motors and the receiver inputs, you get a block of DIP switches for selecting the airframe type and flying mode, and an ISP socket for programming new firmware.  The good news is that there’s already alternative firmwares out there for the Eagle N6 and they work just fine on the i86 too. The even better news: You don’t need to care about getting an ISP board and upgrading the firmware. This controller just works.

Eagle recently released a Version 2 of their controller board, which features an external crystal oscillator for the microcontroller, but lacks support for fixed wing airplanes. In our opinion that’s a bad trade, as the crystal won’t do you much good in practice, while the airplane mode is an intriguing capability considering that most airplane gyros have worse gyro chips and cost more.

The i86 / Eagle N6 supports everything from airplanes to hexacopters and a few more exotic variations. Not bad for $20

Setup is quite simple, you start with a basic airplane program on your transmitter, and don’t change anything (except for the throttle reverse for Futaba owners, but they are used to that already…). Then you set the DIP switches to configure the right airframe type.

To configure the stick center position, just turn the PITCH potentiometer counter clockwise to zero, keep all transmitter sticks centered and the throttle at zero, connect the battery, and wait until the two LEDs stop flashing and only the blue LED stays lit. Then you disconnect the battery, rotate the pitch pot back to center position, and you’re ready to fly!

The only other available configuration mode is activated by dialing the ROLL pot to zero, which will make the board forward all throttle input directly to the ESCs. As you might have guessed, this is used for programming your ESCs for things like throttle range and such. We found that most ESCs work just fine with the defaults however.

This board comes with an arming mechanism that is tied to the elevator input. To arm the board, just move the elevator stick down and hold it there for two seconds, at which time the blue LED will light up. Check that the props are turning in the right directions, and then carefully apply throttle. During your first hover just check if the control directions are correct (we had to reverse rudder direction on our Futaba 12FG) and then you’re set! If the copter feels “mushy” and you have to work a lot to keep it in place, dial up the pitch and roll potentiometers on the controller board. Thankfully changing sensitivity can be done on the fly, no need to repower the controller. Changing airframe type and flight mode however DO require a powerdown.

Speaking of flight mode, the i86 supports a beginner and a “sport” mode. Beginner mode is the default, and will keep the quad much more stable and limit your control inputs to a safe range. This is good for filming and related activities, while sport mode gives you free reign and agile controls.

Flight Performance

Simplicity and cheap price count for nothing if the thing ain’t fly. And fly it does! The thing to keep in mind here is that we are talking about a $20 gyro-only board without accelerometer. In other words, the controller has no idea about its current lateral movement, it only senses rotation. Luckily the STM gyro chip is excellent, sensitivity range is fantastic and you don’t have to fear to go from flying-like-molasses to the airframe flipping over with a fraction of a quarter turn of the sensitivity pots. Just dial up the sensitivity until the airframe starts to wiggle on its own (especially when doing brief quick stick movements), then dial back a little. For the YAW pot, apply plenty of thrust and check if the airframe rotates counterclockwise or clockwise. If it does, increase yaw sensitivity until the orientation doesn’t change much when applying sudden power.

Normal mode feels very stable, even though it has to be said that MultiWii, Rabbit, FF and all the other boards with accelerometer support are a league above this. This is a benign board to hover with, but don’t expect to put down the transmitter and fetch a beer while your quad is in the air. All in all it feels a lot like the KK board, it doesn’t really auto-level but it does a fine job at managing to stay level most of the time, while still giving you a certain degree of maneuverability.

After activating sport mode flight actually feels a lot better and more direct, with the rate limiter now turned off you can pick up tremendous speed or  – in theory – flips and rolls. However, in practice we have been unable to complete a roll with either 9×4 and 10×4 props on a 450-size quad. Scouring the forums shows that a number of users complain about slow roll rates, and increasing your servo travel on the transmitter only gives you so much. It is possible that this may be improved in another firmware revision, but we haven’t found any information about this specific issue being improved yet.

All in all, flying feels neither sluggish nor crisp. It’s right in the middle of things, which is okay considering the price.

Verdict

It’s difficult to fault this board for not having accelerometer support, as it does its job well. Thanks to the simple setup and its versatility, you can even use it as a cheap, yet excellent three-axis airplane gyro. In fact, at $20 this is probably the best airplane gyro you can buy.

Using this controller for quad-copter flying on the cheap? Sure, why not. You don’t have any hassle programming the board, everything works out of the box, and getting airborne is even simpler than with a Rabbit controller. $30 more gets you a board with gyro and accelerometers, and a whole new level of stability that a gyro-only board simply can not achieve. To that end, we think it’s pointless to hope for a future firmware upgrade to magically turn the i86 into a self-stabilizing wonderboard. There’s simply no more stability you could eke out of the poor STM gyro, which does the best it can sensing rotation. What can be improved however is the agility of sport mode. It’s quite good, but not good enough for aerobatics.

The beauty is that even though no firmware flashing is required, you still have that option thanks to the ISP header pins present on the board. There are already several interesting firmware projects in the works, among them a firmware with support for a LCD-driven configuration tool.

There are better alternatives on the multirotor controller market – but they also cost more. If you are strapped for cash or you’re just looking for a cheap and simple board and don’t mind it not magically auto-leveling itself 100% like the newer boards, this is for you. It’s a solid board, super easy to set up, and certainly better value than the aging KK boards.

Update 2013: If you’re looking for a cheap, easy to use multirotor flight controller, check out the KK 2.0 and KK 2.1 boards!

 

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Comments (10)

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  1. alex says:

    hello i have a problem with Hobbyking i86 Multi-Rotor Control Board a guy have flasch the openaero on this bord and now i can´t fly a quad with his my ask givt it a original firmware for the board to flasch it or a other firmware for a quad

    PS:sorry for by bad englisch

  2. Peter says:

    Please help me guys. My flight controller not working, just beeping slowly after turn on battery and after unarming beeping fast and blue LED turn on… No more! And if I trying arming board back, blue LED will turn off and beeping slowly again. Please tell me how I start motors, thank you very much!

  3. Peter says:

    Wooow, works perfect, THANK you very very much 🙂

  4. Paul says:

    hey all, my i86 just came and ive got it all set up. upon power up i get three rapid blue lights (tricopter mode) then when i hold down the elevator to arm it… nothing happens. any ideas???

  5. Marcus says:

    Please help me guys. My flight controller not working,I connect it and I have just Red flash… nothing more, What’s I can do ?

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