I just got the Walkera QR Ladybird nanoquad and it's just frankly amazing. For $140, you get the quad, a 7 Channel 2.4 digital Devo 7 RC set with graphic backlit LCD display, a 240MaH LiPo and a LipPo charger. It can fly inside and out and has much better range than a Parrot AR.Drone (thanks to the proper RC gear). The RC gear alone is worth nearly that price (you can buy additional receivers for it here)!
Walkera says that it includes RC telemetry for battery and flight controller status:
1). Onboard telemetry system enables real-time monitoring of receiver, gyro, mix control and speed setting.
2). In-built telemetry function also enables and simplifies flight battery voltage monitoring.
We had a great time flying it around the living room. It's very stable, but as you would expect from a quad, very maneuverable. The transmitter starts up in regular mode (not dual rate or exponential, both of which are options), so it requires a very light touch on the sticks. A couple clicks of the trim and it will stay in one place. Because it moves fast and is so small, it's pretty easy to lose control in a small space, but the airframe seems quite robust. We crashed it lots of times, and just had to superglue on one of the motor holders after it cracked. Good as new!
Here are some shots of the incredible integration on the single flight controller board. It says it has a "six-axis gyro", but I think that must be a mis-translation from Chinese. It's probably a three-axis gyro and a three-axis accelerometer. Alternatively, it could just have a three-axis gyro, like the simple KK boards (in which case I don't know that the other three axes are supposed to be)
Top of the board, showing the flight computer and RC receiver
Bottom of the board, showing the motor controller microprocessors and four speed controller circuits.
Here's how the LiPo fits on the bottom:
A sense of the RC transmitter display
And a video in flight:
Comment by George P. on May 2, 2012 at 2:19am Not possible.
Ladybird use brushed dc motors and the ESC for this type of motor is very simple: Only one MOSFET and the PWM signal from microcontroller.
4 motors = 4 tiny MOSFETs (see on the bottom side of PCB) and 4 PWM ports from microcontroler.
And that was it.
Ηowever a brushless motor need very complex control and therefore each brushless ESC need:
1) Its own microcontroller with built-in 3-phase motor control hardware.
2) At least 6 MOSFET.
3) 3 half bridge IC drivers
4) Sensorless rotor possition detect circuit.
5) Tight current monitor circuit
6) Voltage monitor circuit
7) Linear BEC or at least 2 voltage regulator circuits.
If on one PCB you have 4 b.l. ESCs with all the above parts x4 and one Mosfet or other sensitive part burned, then entire PCB and the other 3 operational ESCs is out of use.
Comment by Ellison Chan on May 2, 2012 at 8:02am George, you'd save some space by using one processor that's fast enough to control 4 motors, and you would not need any regulators for the BEC, since the main board would have a beefy one that can handle the electronics. You'd also optimize the circuit to minimize the size of PCB you need. There would be some advantage to having 4 escs on one board.
The disadvantage is that any failure means replacing the entire board even though some of the motors are still working.
Comment by Dez Socks on May 3, 2012 at 6:26am Thanks for the reply guys.
I'm not sure of cost but maybe one board could also cost less than 4 separate ESCs so replacement is also easy.If say we had a failure in one motor maybe build something else with it like a tricopter or plane but hopefully it wouldn't come to that.

Comment by Dave C on May 5, 2012 at 1:22am Mmm it seems to me that you can only fly this with a devo transmitter - is that right? I got a bind a fly version and cant find any info on binding it to my dx6i or t7c - maybe i should have read more before hitting buy it now....
Comment by james sowell on May 5, 2012 at 2:17am yeap I need a breathalyzer on my buy now button ; )
Comment by Ellison Chan on May 5, 2012 at 5:11am Dave, from my reading of the manual, Devo only and it comes usually with a Devo 7.
Comment by Tom in ON on May 5, 2012 at 6:14am It also says that only with the "s" version of Devo transmitters is telemetry available.

Comment by Dave C on May 5, 2012 at 12:19pm Yes I thought I would be sacrificing the telemetry but still be able to bind for flight functions... Does anyone have any idea why Devo only, and is it hackable?
Ellison, do you have a Devo transmitter then? Can you bind that to a non-devo receiver?
Comment by Ellison Chan on May 5, 2012 at 12:29pm Dave, no I don't have a Devo, but considering, since I've been looking at the specs. The good thing about Walkera, is that the use the same radio across the line, so they're compatible with multiple craft. Unfortunately, they are not following any standard, so are not compatible with other manufacturers. At least the Devo 7 is decently priced.

Comment by Dave C on May 5, 2012 at 12:35pm Yes, it looks good, but really I have enough 7 channel tx's kicking around already. Ah well, I can always sell one of the others if I like the Devo.
It looks like I'll have to wait till after the bank holiday, so I can swap it for a full version with TX, before I get to fly my ladybird.
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