This is an archived post. You won't be able to vote or comment.That thing is INSANE! (youtu.be)submitted by π Rendered by PID 85995 on app-793 at 2017-03-08 14:44:44.395237+00:00 running 9af7935 country code: SG.Oneshot125 is a new ESC protocol to replace PWM. In this post we will explain what Oneshot is, and the new BLheli feature, Active Braking (damping light) that help improve the throttle responsiveness. An ESC protocol is used to communicate between flight controller and ESC. It tells the ESC and motor to go faster or slower. Originally this is based on servo position protocols, which is a PWM signal between the values of 1000ms and 2000ms, 1000ms means stop, 2000ms means full speed. But PWM is kind of slow, and susceptible to jitter, and that’s why Oneshot125 is introduced. Oneshot125 is a faster ESC protocol born in the mini quad FPV world. It’s synced to the PID loop, therefore it’s less jitter. Also it uses shorter signal so the FC can talk to the ESC/motor much quicker, and therefore in theory your multirotor should perform better.

You will need to have Oneshot feature enabled on both your Flight controller and ESC (Electronics Speed Controller). In this post we will discuss how Oneshot is better, and how to enabled Oneshot125 on the ESCs. We will also discuss Active Braking (Damping light) briefly at the end. Here is a tutorial how I flashed BLHeli firmware on my Blue Series ESCs, and have oneshot enabled. I also compared the performance against SimonK. With OneShot, motor_pwm_rate is disabled in Cleanflight, so it doesn’t matter where you set it. Flight Controller (FC) has a main control loop that calculates a new value according to the data from sensors. The motor output loop then pick up this value from the main loop and sends it to the ESC constantly. But the time it takes to complete a FC main control loop is not always the same, sometimes it takes longer, sometime shorter. The motor output PWM signal sends whatever value is available, if there is no new value it will just use the old value.

If we are lucky, the ESC might pick up a new value from the FC it just produced. But sometimes a new value is not being picked up yet, maybe because the ESC is still writing the old one to the motor, then we consider this value we are writing an “OLD” value. It hasn’t caused any major problem in reality with this approach as we have seen, we are talking about only a few 0.001 seconds difference here. rc predator drone buildBut some people has come up with a “fix” for this.rc uav drone for sale Diagram from multiwii forum, link at bottombest ar drone mods So the solution is to synchronize the main FC control loop with the motor output signal.ar parrot drone 2 price

Firstly, Oneshot125 sets the motor output timer speed 8 times faster. The motor output signal is now much shorter (125us-250us) than the original PWM (1ms-2ms), so it takes less time to send and the ESC can read the data much faster. The problem before as mentioned, was sometimes the value wouldn’t change on the ESC until half way through a control loop. Secondly, it only sends “one shot” of the signal every flight controller loop, and it does this as soon as the Flight Controller has a new value for the ESC. mq-27 dragonfire drone with remote control for sale(I am guessing maybe this why it’s called “oneshot” :) )best drone with camera The ESC is now writing a new value to the motor, even before the FC is starting the next control loop, so we have the fastest possible FC and ESC Response.

Pilots that have tested it reported P value can only be increased a little (not major improvement on PID gains), but the biggest change was to throttle response, faster change of motor speed. Check out this post for some simple explanation of Quadcopter PID. To have Oneshot enabled, all of your ESC, ESC firmware, FC, FC firmware have to support this feature. ESCs that have BLHeli rev13.0 or newer version flashed supports Oneshot, and it will be automatically selected without additional work. I believe SimonK now also supports Oneshot. As far as I know, only the Naze32 boards with Cleanflight are supported perfectly currently, without any issue. The CC3D boards have been tested with a PPM receiver, however parallel PWM receivers might not work properly with this board. I have heard that’s because the motor output pins shares the same timer as the receiver pins. That’s a fundamental issue and is going to be difficult to fix. The process for calibrating oneshot ESCs is the same as any other ESC.

Active Braking is a feature in BLHeli firmware, many people enabled this along with Oneshot125 to get more responsive result. With damping light (Active braking) enabled, when you reduce throttle the ESC will actively reduce the motor speed. Without it the prop will only be slowed down passively by the air resistance as you drop throttle. This is especially obvious with longer larger props than smaller props, due to inertia. Many observed when this is disabled, the quad feels more “floaty”, when enabled, the quad feels more responsive with throttle changes. Hydra showing the difference between normal PWM and Oneshot on a Oscilloscope. There are now even more advanced ESC protocols on the market. Check all the props for damage and debris around the shafts(string and things like that). Other than that make sure you have a fully charged battery I had the same problem after switching my propellers out, my drone (X5SW) didn't want to lift and kept tilting to the right.

After some searching I found that if you don't have the propellers in the right sequence, that you're not going anywhere. I switched the props to the picture on the box and low and behold, I'm flying again! If the motors are spinning up, it is likely an issue with the flight controller or ESC's. Have you tried calibrating the gyros? Turn the copter on and place on the level surface, I believe it is both sticks down and to the right (might be left, varies from manufacturer), hold and watch the LED's on the bottom flash, once the flashing stops it should be calibrated. I have seen that happen before after taking a crash. If the gyros don't agree with each other it won't fly. Do the motors actually respond to the throttle up to point? Meaning you can spin them up and down a little bit just not enough to take off? Or is it just spinning in Idle when you turn it on? Also, I'm not sure if it was a question or just a comment, but you should always have 2 motors spinning clockwise, and 2 counter clockwise.

On a lot of these toy grade drones if you get hung in a tree and the transmitter is still throttle up you are going to burn out something. I had issues when I was new to the hobby, so I feel your pain. Props are marked A and B. Make sure they're mounted on the correctly marked arm of the quad. Motors cost nothing a few pounds for a set of 4 . If u crashed it u more than likely damaged the motors or control board. Check all the solder points are ok and no wires are detached. If thats ok and the motors rev up and respond to transmitter power then the board is naf. U can bypass the power control by placing a small blob of solder on the board in the right place. This bypasses the gyros and enables normal flight again. The gyros perm set at default so no need for calibration. When your thing is spining but is not going up in the air what do you do . Posted: March 7, 2017 i have kk5.5 board...ive made xcopter....all the motors are rotating perfectly.... 2 motors in clockwise and 2 motors in counter clockwise direction but the problem is the drone is not lifiting off...can u say a solution for itttt....