"Single chip" 4 in 1 ESC?

I'm trying to build a micro drone/quadcopter based on an Arduino Mini 05, but I need some tiny ESC's to get this to work...

I started off buying some palm sized toy drones, and opened them up. There is just one PCB in there with a lot of electronics on both sides of course.

The ESC on these things seems to be just one chip with 4 transistors (for all 4 motors), problem is that the manufacturer scratched off the info on the chip, so I have no clue on where to find it (or something similar of course)...

But knowing the chip is still not enough I guess, so: Does anybody know of any schematics on how to create such an ESC to control 4 tiny motors?

On small quadcopters, it's a simple N-channel mosfet. Nothing special there.

Choose a suitable small N-channel, logic-level mosfet and be done with it.

// Per.

The small drones don't have ESCs since the motors are DC coreless, not BLDCs.

BTW if you want good fast speed control you might want half-H-bridge per motor
rather than a simple FET, so that you can rapidly reduce speed as well as increase it.
Whether this is worthwhile depends on the relative effects of air-resistance slowing the
prop when undriven and the electrical braking effect of shorting the windings. Its hard
to know without some experimentation. Certainly smaller copters need faster control
loops due to the low MoI allowing rapid flipping, so the speed of modulating thrust will
be relatively more important.

I spend hours looking in the wrong direction

But this is great! That's not hard to make (even on SMD), so thanks for the detailed information!

The only problem with the smaller quads is the payload (your electronics) has to be smaller
and lighter, which creates issues. However the motors and props are so cheap on eBay these
days its tempting!

This should be small and light enough, it's for all 4 motors... I could also put every "controller" in the quads arms to reduce some weight, but I think it won't matter too much... The 9 axis gyro is even smaller than the arduino mini itself, so all 3 combined + smart short wiring + a thinner lighter battery (same or more mAh as the standard battery of course) should work fine...

Neat work - SOT223 devices?
Just need one of these too: http://www.engadget.com/2007/04/12/gr-10-gps-receiver-plays-the-worlds-smallest-card/

Wow, that's tiny, and the price isn't that bad at $58.46... Ok, you have to buy 10, but I can probably sell a couple and even make a profit

But I think it's best to start off by making it fly stable first I'm still looking for some tiny ultrasonic modules (or IR, but I think ultrasonic is better for height), because the ones I have are too large/heavy, and using a barometric sensor would not be reliable indoors where I want to start off my project...

Barometric sensors work indoors fine. Air still has density inside a building!

MarkT:
Barometric sensors work indoors fine. Air still has density inside a building!

Of course but when you open a door the density can suddenly change which makes it less reliable right?

But let's get back to the motor controller circuit, everything is hooked up now, the motors turn nicely (and in the right directions) but they draw too much power, when I set all 4 PWM ports to 90 the arduino resets itself... I can just make it to 85, but sometimes it does reset, sometimes it doesn't on that value...