The correct VBAT_SCALE is 135 (default was 131 before). This has been verified with a variable power supply to be within 0.1 volts accurate through the range of 2-12 volts. I have updated the firmware tool but your saved profile will not automatically update.

I've also discovered a bug in MultiWii 2.2 where a change of the VBAT_SCALE in firmware requires a RESET in the MultiWiiConfig GUI before the VBAT_SCALE takes affect. Until you hit RESET the voltage monitoring will continue to be incorrect.

If you are reading a voltage of 0, then you probably haven't wired up the gray VBATT wire from the EZ-Connect Radio harness. This is the 3rd wire counting from the right of the cable. The black GND wire is on the right and there are two gray wires next to it, VBAT and VIN, you want the 3rd one in. See EZ-Connect Wiring System.

This indicates that the Quadrino is not receiving the channel signals from the receiver module. Check that:

1. The receiver unit is getting proper power. The receiver unit should be powered from the Quadrino by the red and black wires on the RADIO cable.
2. The receiver has been bound to the transmitter. You will have to consult the manual for your transmitter on how to do this.
3. The RADIO channel signal wires are connected to the right pins on the receiver module.
4. The correct receiver protocol has been selected within the Firmware Config Tool (Options | Receiver | Rx Protocol).

Receiver Protocol

It is important that the correct protocol be selected in the Firmware Config Tool. If you have one wire for each receiver channel, then you use Standard PCM! If you have 1 signal wire for *all* channels, the you use PPM SUM. Don't let the Transmitter Model selection box fool you, this box only matters if you are using PPM SUM protocol, and it is only used to select the channel order in PPM SUM mode.

Everything is working like it should except for the tailservo. The servo is "centered" in the extreme right position (output 2000 in the config program). The input from the receiver is ok, everything is centered and endpoints are adjusted correctly. Tried to connect the servo directly to the receiver and it was all ok. Tried different servos as well.

This is caused by old QUAD eeprom/flash settings getting stuck in the on-board flash area and corrupting the tricopter configuration. Go into MultiWii Config GUI, start the data rolling, then hit the RESET button which will clear out all settings.  Now your tail servo should be working properly. Reconfigure your PID and AUX settings and hit SAVE.

This is a known issue with MultiWii code, I am trying to figure out a good fix for it in software.

FYI You will need MultiWii firmware version 2.1 or above to get the RESET button, the RESET button didn't exist in version 2.0. If you don't hit SAVE after the RESET then the corrupt settings will return on the next power up!

As of August 2012 all units are programmed with MultiWii V2.1. Some units purchased around that time may still be 2.0. Both 2.0 and 2.1 give excellent results, the altitiude hold seems to show some improvement in 2.1.

MultiWii 2.2 is now available and you can easily upgrade using the Firmware Config Tool on any Quadrino board.

The wobble of death crashes are typically due to MINTHROTTLE being set too low (ESC tab). It's important to verify this setting for each copter build because it is different across many brands of ESCs.

What happens is during banks sometimes a motor throttle level (as commanded by the Quadrino) may drift below the minimum throttle level of your particular ESC and the motor will go into shutdown. When an ESC shuts down it will take some time to spin up again. Thus, the copter control system and other motors go kind of crazy because they are trying to compensate for a down'd motor. Only with significant altitude may the copter recover.

Sometimes I am able to make a motor spin down while the throttle is just beyond the start-up threshold where the motors are at the lowest power level. If some motors start and others don't, then the MINTHROTTLE set in the Quadrino Firmware Config is definitely too low. Increase the value in increments of 25 until all motors start and stop together while toggling the throttle threshold. Also, with the motors spinning at the lowest power, do banks with the roll and pitch stick. The copter should be too under-powered to actually move much but the motors should never power down during the motions. In other words, the Quadrino keeps the motor output above MINTHROTTLE so as to never cause a motor to enter the shutdown state when in flight.

For proper flight operation a MultiWii board must have it's MINTHROTTLE value set just slightly above the internal minimum throttle level of your ESCs. Unfortunately, there is no way to read or determine this value other than by trial and error. Furthermore, different ESC brands, and even different batches can have different min throttles. Also, setting min throttle too high will fix the wobble of death issue but may cause your copter to take flight the moment the motors are turned up. It is for this exact reason the default value of the Quadrino is set quite low (1175). By the way, calibrating your ESCs together can bring the ESCs min throttle down to a lower point and is highly recommended.

The ACC mode, or auto-level, has been renamed to ANGLE mode and the behavior hasn't changed.

HORIZON mode is a combination of the ACC/ANGLE mode and regular acrobat mode (no auto-level). When you are not touching the roll/pitch stick then the copter auto-levels, but when you start putting in bank or pitch angles then the copter morphs to acrobat mode. This mode is basically a flip-trainer. It allows you to full bank or pitch to begin a flip and then let go of the stick to have the copter right itself. It really works, and is an awesome feature, but you can still crash the copter if you attempt it at low altitude.

You arm the motors by throttle all the way down and yaw all the way to the right. The yellow STATUS light should turn solid. To disable the motors use throttle down, yaw left.

If this doesn’t work, you have to make sure the channel ranges of your transmitter go from <1050 to >1900. These gestures don’t work if your transmitter is not properly configured and most do not come with properly configured channel ranges. See the Transmitter Tutorial.

This can be caused by two things. One is caused by high differential currents travelling between the battery and the ESCs - those large red and black wires on your power spider cable. If these are too close to the magnetometer then the sensor will read these differential currents like a magnet affects a compass.

  We typically don't think DC current creates an electromagnetic field but during changes in throttle or motor demand the amount of amperage changes thus causing Alternating Current, even though the voltage stays constant. Only during the change in current draw does an electromagnetic field develop. Once amperage stabilizes the system returns to DC current laws and thus no EM field.

You should be able to solve this by adding more space (standoffs) between the center plate and board. You may also be able to use EM shielding (try tin foil) but this will shield the sensor from the earth field too depending on where the shielding is and the copter's orientation. Basically, the shield may create a shadow in the earth's EM field and depending on the quad orientation the sensor could end up in this shadow. Perhaps shield the spider cable itself, like cable TV coax cable shields the inner core. The shield should be tied to GND as well so the EM currents have somewhere to go.

The other reason could be an imbalance of the copters' props, motor output, or thrust vectors because of any of the following:

1. damaged or unbalanced props
2. bent motor shafts - possibly caused by crashes or improper torquing of the motor shaft during prop installation.
3. bad/worn bearings or fatigued motors
4. frame out of alignment or loose - the props thrust vectors are not all pointed directly up

Diagnose and correct each of these issues. A prop balancer can be bought cheap on many RC sites. Bent motor shafts and worn bearings can often be diagnosed by hearing a rattling sound when you spin the prop/motor by hand. The motor rotation will sound different than a motor and prop in good condition.

To check frame alignment, place the copter up-side-down onto a flat table. Turn each prop slowly to check that the prop is always parallel to the table surface as it completes a rotation. Usually it suffices to correct mis-alignment by torquing the frame back into alignment and retighten screws - then recheck. A properly aligned frame does make a big difference in overall flight performance! 

A loose frame can be secured using a neat RC modelers trick. Fill the loose frame connections with baking soda, then add a drop of crazy glue to the baking soda. When baking soda and crazy glue mixes it forms a plastic styrene-like material that fills in the cracks solid. Crazy glue along can work, but since it doesnt actually fill the cracks it isn't as strong overall.

No! :) LEDs take a lot of power when you are talking about 5v or 12v systems. LED power is a drop in the bucket when you are talking about power from a 120v line and comparing power to regular incadescent light bulbs or even CFL ones, but not so when you are talking about micro systems. Your 100w light bulb takes as much power as your desktop computer and flat-screen monitor, seriously!

Each LED takes 60mA (0.060amps)...so add them up. If a strip has 12 LEDs then you are talking 0.72 amps...that would burn out a typical linear regulator such as one you would buy at Radio Shack. Well, actually, the linear regulators have a thermal shutoff so it wouldn't kill it, it would just turn your LED strip into a blinker.

You can directly connect the 12v LED strips to the battery, they are meant for unregulated 12v power.

[This question only applies to using the pin headers, not the EZ connect cable.] In V1E units and later you can plug in all ESCs now because I’ve rewired the board pins to only pull power from ESC Motor-C connection. 

Also, in the older boards you could connect them all together. Since it is in parallel, it doesn’t create 20volts but just 5v with more current capability. Although we often connect batteries in parallel and series, I never see power supplies connected together, It’s just a bad idea. If you have the V1D or earlier, you should connect only one red wire.

It is normal for the motors to beep a few times during startup; usually playing a melody. If they continuously beep at regular intervals then it means the ESCs are not getting any RC signal. Check and re-check your wiring!

Ensure proper board operation by using a battery at the same time as USB and use the MultiWii Config GUI to ensure the board is communicating OK. If the Quadrino is communicating with the GUI then it is definitely a wiring issue as the Quadrino sends the RC signal from the moment it powers up.

Check the following:

1. Are all motors beeping, or only 1 or 2? It can be hard to tell when they beep in sync.
2. EZ-connect is fully inserted into the board. Remove the cable and re-insert it.
3. 3-pin connectors between the EZ connect cable and ESC are fully inserted.
4. Check that there is a path for ground (GND) between the Quadrino and each ESC.

VCC is the technical term for positive (+) regulated system power. In this case it is 5 volts, colored RED, and along with the black GND wire powers the receiver module. So plug the RED and BLACK wires into the receiver module. Most receiver modules have (+) and (-) pins along with each channel so any of these will do.

If you are powering the Quadrino using an ESC it is likely that you have a blown protection diode. This diode is labeled D2 and is located just above the middle slot in the board. This diode protects the ESCs from USB power coming from the computer, and thus preventing the chance that you might get bit by props when plugged into USB, (as has happened to me way back.)

The cause of the diode blowing is the board's (+) supply was at least momentarily connected to GND(-). First, ensure your wiring is correct and use a multi-meter to ensure power lines are not shorted. This is called a HI-POT test.

It can simply also have been caused by a stray screw or exposed wire shorting the power pins, so your wiring maybe fine after all. The advent of the EZ-connect has largely rid the case of blown diodes since power pins are no longer directly exposed.

Open a ticket with us and we will solve your problem. We will either send you some spare diodes, or you can send your unit in to us and we will replace the diode free of charge.

All units are tested under MultiWii Config to verify that all sensors work and produce sensible results. All the following systems are tested before shipping: PowerOn Test (HiPOT), USB connection, Atmel ATMega328P, Gyro, Acc, Mag & Baro. This is a working test of all electrical circuits. A regular number of units are also flight tested to maintain quality control. Also, all warranty units are flight tested before return shipping.