[STLhive.com]

I am VERY impressed!
i would love to know more!
i'm sorry if i missed some info by not reading carefully enough:
Is this still using an Arduino?

Shane

[vaalleon]

Originally Posted by STLhive.com

I am VERY impressed!
i would love to know more!
i'm sorry if i missed some info by not reading carefully enough:
Is this still using an Arduino?

Shane

Hi, thank you very much! Yes, I have 3 boards (RX, Arduino, Multiwii) and 6 IR sensors on the unit right now. Arduino board is between the RX and the FC and mixing the IR signals with the TX signal. The problem right now is that daylight interference. In closed areas everything works good but out side the proximity sensors failed to do the job...

[vaalleon]

I tried for a while to make the IR sensor immune to daylight but it was way over me technically. I tried to send and receive the light in a certain frequency but that didn’t work…

It felt more my way, to teach the Arduino about the outside world instead of limiting it to a signal anyway. During my tests I saw that daylight, especially direct sunlight have very strong IR radiation. So, I started working on a code that will recognize the environment and command the unit accordingly.

The code is recognizing the environment by calculating the average value from all 6 sensors and initiating 2 different algorithms accordingly. It also has a control against the effect from the direct sunlight. Otherwise, the unit would give a very strong response to direct sunlight.

I also improved the hardware by covering the back of the sensors and placing them in tubes to minimize environmental effects.

It works fine indoors. I will see how it reacts outdoors tomorrow. When it is ready I will do the first flight test with the IR sensors, hopefully outdoors.

[vaalleon]

Focusing on the indestructible Nano recently, I haven’t been able to work on the MonoBot. Having the nanoC resolved, I had a chance to revisit the bot.

Since the maiden flight and realizing that the regular IR sensors are useless in daylight, I worked on a solution which I hope would solve this problem. This solution utilizes the sensors almost like motion sensors and they react to changes in the environment, whether this is an obstacle or a change in the light source, etc… But I never had the chance to test this until a couple of days ago.

This time the problem wasn’t the IR sensors, in fact I could only test them in one occasion during 18 minutes of trying. The servo jitter that I kinda solved with the filtering code and the delay that the code causes were the major problems. So, I tried to control the unit most of the time and didn’t feel comfortable to activate the IR sensors except one occasion and that short video is attached. At 24 second mark you will notice the unit ascend and bounce back with the help of the bottom sensor. However, probably, because of the noise in the signal and the delay caused by the code, the second bounce didn’t happen and the throttle was all over the place during that time.

After experience, I tried hardware solutions one more time, pull down/up resistors, capacitors, different feed voltages, feeding the Arduino board from a separate source, etc… One more time, nothing worked… I believe this is an Arduino nano problem and there are lots of blogs but no real solutions. And I am pretty sure if I used a UNO board I wouldn’t have this problem but that is too large for the unit.

So, I camped in front of the computer for 2 nights to sort this problem with a new code. After many unsuccessful tries I believe I came up with a better solution, which eliminates the jitter COMPLETELY and improves the response time significantly. The second half of the video shows the results. The shaking of the nozzles for a second right after I boot up the unit is because of resonance and has nothing to do with the signal quality. After that one second you will see that the nozzles are as still as rocks, which makes me very happy.

Will adjust the response rate of the sensors and test it again once the weather conditions allow me…

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[vaalleon]

I had to go back and do everything all over… I couldn’t, for the life of me, achieve a stable flight with the previous setup. Every time I thought I solved the problems, something new came up. The last problem was that the X/Y/Z values have been slightly changing independently based on the values of the other axis. When I was adjusting the yaw, it was impacting roll. So, I could never get the unit to a stable flight where I can test the sensor. I believe the problem was that the PPM signal that I fed into the flight controller was causing the problem and the FC was getting confused, maybe because the signal from the Arduino uno wasn’t all that high quality… And with this flight controller, I couldn’t feed in PWM….

So, the decision was made and I replaced the flight controller with the one that I used on the indestructible Nano. Re-wrote the code to replace PPM with PWM, and fed that into the FC. I took off all sensors, to install new ones in the next stage, if the unit flies well.

It worked. At last I passed the signal through the Arduino and achieved a stable flight. There is a slight headwind during this flight so I need to manipulate the unit to beat that. I am really happy with the result. I still have the jitter avoidance code working at the background and causing a little delay but, it didn’t impact the flight, except the landing, where the throttle cutoff was slow and caused the unit to flip, which is nothing new.

Now the signal is ready to be mixed with the IR sensor inputs. But this time I will be testing some obstacle avoidance sensors instead of my old home made distance sensors. The new sensors create a signal which is either 0 or 1 but the code is capable of softening this and adjusting the output based on the length of the signal. According to my tests, they are also immune to daylight, not 100% but maybe 90-95% (direct sunlight may cause issues). If the unit gets out of control I will disable the sensors with the 5th channel. First I will test only 1 or 2 sensors to see how the unit reacts.

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[vaalleon]

AT LAST!!! The first time that I could really test the IR sensors during the flight. Currently have two sensors, one at the front and one at the back. I used my right hand as the obstacle to activate the sensors, whenever I felt comfortable enough to take my hand of the stick. The unit gently moved to opposite direction each time Really cool!

I will increase the impact of the sensors a little bit to make the unit react faster and will add 4 more sensors in all directions.

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[vaalleon]

I decided to go with the hard one again… Will use what I learned to try building a GPSless position hold system via a GY-521 sensor board + Arduino. This is a pretty cool little board which has accelerometers and gyros. Below data is from my serial monitor… Need to build a solid algorithm using the accelerometer data. Hmmm…

AcX = -2200 | AcY = -68 | AcZ = 17424 | Tmp = 31.82 | GyX = -501 | GyY = -38 | GyZ = 249
AcX = -2244 | AcY = -36 | AcZ = 17292 | Tmp = 31.97 | GyX = -444 | GyY = -22 | GyZ = 173
AcX = -2224 | AcY = -52 | AcZ = 17328 | Tmp = 31.87 | GyX = -450 | GyY = -64 | GyZ = 258
AcX = -2260 | AcY = -204 | AcZ = 17236 | Tmp = 31.92 | GyX = -432 | GyY = -59 | GyZ = 231
AcX = -2192 | AcY = -36 | AcZ = 17232 | Tmp = 31.92 | GyX = -436 | GyY = -51 | GyZ = 167
AcX = -2308 | AcY = -44 | AcZ = 17268 | Tmp = 32.01 | GyX = -513 | GyY = -15 | GyZ = 267
AcX = -2232 | AcY = -216 | AcZ = 17264 | Tmp = 31.97 | GyX = -472 | GyY = -2166 | GyZ = 252
AcX = -2108 | AcY = -2012 | AcZ = 15580 | Tmp = 31.82 | GyX = 96 | GyY = -935 | GyZ = 5553
AcX = -1040 | AcY = -2932 | AcZ = 18424 | Tmp = 31.87 | GyX = -2685 | GyY = 4202 | GyZ = 3258
AcX = -3316 | AcY = -284 | AcZ = 19688 | Tmp = 31.92 | GyX = 633 | GyY = -435 | GyZ = -1965

[vaalleon]

Implementation of what I learned with this project to my indestructible Mono.

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[vaalleon]

The new indestructible MonoBot. No more replacing servos, fixing landing gears, etc…. This unit is extremely durable and light and will be the new base for my ongoing Arduino tests. Flies like a charm!

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[vaalleon]

This is my new carbon fiber unit that I will use for testing and experimenting sensors and position hold systems, as a part of my ongoing arduino project. This is the maiden of this unit. After seeing that it flies in the first couple of seconds, I felt comfortable enough to immediately test the GPS. I tweaked the code earlier to make the GPS to refresh the position hold position as the point where the stick is released. In the old version, when the stick was released, the GPS would take the unit where the GPS hold was originally initiated. However, with the change, I could successfully re-assign the new position hold coordinates as the point where the stick is released. This will be very useful in many projects. I call it the crawl mode. thx

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