ArduinoDeXXX

こんにちはまず最初の御質問ですが、詳細はStep13の最後の段落とそこのリンク先をご覧ください。サンプルコードはどちらの状況にも対応できるように「alternative line」をコメントアウトした状態で付けています。2番目のご質問ですが最適化の解です。解析解ではないのでなぜそうなのかは私にも分かりません。3番目の御質問ですが不連続な点はないはずです。英語版の方で同じやり取りをしたことがあったので調べてみましたが見つけられませんでした。慎重にやり直せば大丈夫だと思います。

All I can tell you are described in the earlier comments. See the replies for jgomezu below.However I can tell you an additional point that you should use D9-D10 pins in MEGA not A9-A10.I see the web-site you tell for ax-2804. In it, reviewer MadMaxO posted “I bought 6 units of this motor and only 2 of them work.” Your motor may be similar to the rest four.

こんにちはご質問、Step5の「invertedRobot_v20_noTimer.pdf」に基づいて回答しますね。１．積分処理角速度の離散サンプリングで、i回目とi+1回目の経過時間をΔT_iとすると次のような角度の評価値を考えることができます。・角度の評価値θ＝初期値θ_initial＋Σ（過去の角速度の評価値ω_i × ΔT_i）この時、初期値θ_initial＝0で、ΔT_iの値がiによらず安定している（ΔT_i＝ΔT）としたら、このθは次のように書けます。・角度の評価値θ＝ΔT×Σ（過去の角速度の評価値ω_i ）一方、Step5の「解説（3）」の制御の方程式では、この角度の評価値θに対して適当な係数k1が乗じられます。サンプル・コードでは、72行目のｋAngle/200が、k1×ΔTに相当します。2．recOmegaIの取得タイミング角速度の評価履歴はサンプル・コードの71行目で更新しています。3. recOmegaの役割倒立振子が良いバランスを取ると、角速度はゼロもしくはゼロに近い数値になります。サンプル・コードではこの状態の角度評価値θをゼロにリセットして、誤差の累積による評価ドリフトをキャンセルしています。この時、角速度の評価値にノイズがなければ評価履歴は不要ですが、ノイズがあると一定のフィルタリングが必要になります。サンプル・コードでは、これらの機能は60行目から70行目で実装されています。

Hi,It seems that standard gimbals in market are built with carbon plates. However for a standard DIY maker it may be difficult to use carbon plate. I think aluminum plate will be the first choice for her/him if she/he has good tools to cut and drill it.

Hi,I have gone to sea for fishing and spearing frequently this summer. I just came home yesterday. So I have not used Pi and Python in the last 3 months at all. Sorry, I don’t know when I will use them next time. I think I will return to them in this winter.

I don't know the algorithm "fusion", sorry. I am glad I could know projects where it works.

You need not mind centrifugal force, because a gyro senses angular velocity not angular acceleration.And you can find some BLDC motors in web which you want. For example:https://www.alibaba.com/product-detail/Brushless-Gimbal-Motor-AX-GM-2212_60092183924.htmlIf you got it, see Step 10. You could get your single axes gimbal.

In the sample sketch in Step 10, “OmegaD” is 10 times angular velocity which is measured by the 1st gyro attached to the mount side. And “OmegaDa” is 10 times angular velocity which is measured by the 2nd gyro attached to the camera side.If you have each value of these 2 variables already, submit them for these 2 variables. The sample sketch could work.

See the later part of Step 5. If you do not mind using the special function in MPU, I think you could get 3 axis gimbal with only 2 chips.

Hi,I see what you meet in this project. Itseems that your RPi works well with Arduino, because your servos work well.They could not work well if the communication between these two boards is notgood. Unfortunately I'm traveling now. Can you wait about a few weeks?

Hi guys, I am glad to hear you like this. Thank you.

I am glad to hear you like this. Thank you.

Generally speaking, it is desirable to provide a dedicated battery for each controller. Especially Raspberry Pi 3 requires 2.5A current. Popular batteries in market might not supply it. Further, 0.5A or more current would flow into even a small hobby motor. Hence we should adequate battery/batteries for our stuff.However I use only one battery in this project, which can supply enough current for stuff. See the picture in Step 15. This mobile battery has two USB outlets. One is connected to Pi 3, and the other connected a USB hub. The latter is plugged with two USB cables. One supplies 5V to Arduino and the other supplies 5V to Motors including 2 servos. A cheap USB breakout board in market is used to supply powers for these motors.The pictures in Step 6 and 10 are cut off at both sides....

Generally speaking, it is desirable to provide a dedicated battery for each controller. Especially Raspberry Pi 3 requires 2.5A current. Popular batteries in market might not supply it. Further, 0.5A or more current would flow into even a small hobby motor. Hence we should adequate battery/batteries for our stuff.However I use only one battery in this project, which can supply enough current for stuff. See the picture in Step 15. This mobile battery has two USB outlets. One is connected to Pi 3, and the other connected a USB hub. The latter is plugged with two USB cables. One supplies 5V to Arduino and the other supplies 5V to Motors including 2 servos. A cheap USB breakout board in market is used to supply powers for these motors.The pictures in Step 6 and 10 are cut off at both sides. Click them, you can see whole schematics.

At this time, all I provides are shown here, because this electrical ornament has been disassembled already. However if you post something that prompts a new or additional discussion, I can reply for you in the discussion. For example, if you post a schematic you can draw, I might be able to tell you some advices, even if the schematic has several or many defects. I think it is very natural that a beginner looks up the information and studies something with trial and error.

Hi,You can see stuff working on a breadboard in Video (2) in Step 3. Click the heading picture in Step 3, you could get schematic. Can you draw schematic and post it here?

I have already posted the reply to you yesterday. See the reply for your earlier question.

I think the pictures you attached are close to my idea. However, I cover only 51.429 degrees to control, though they seem covering 360 degrees. Here 51.429=360/(14/2) and 14 is the number of poles in BLDC. Also I use no trigonometric function, because I approximate the arc with 51.429 degrees as a short line.I recommend you to draw two figures, each of which has 3 line charts. One is based on the sample sketch attached in Step10, and the other is based on the pictures you attached. I think they will be similar to each other. If you draw them, post them please(*). (*) Reader vonkross has posted good comments and figures a few years ago. One of them is the former figure above. Now they are disappeared unfortunately.

I read your comment posted to my YouTube video. I reply for it here. I think a wire in your BLDC may have been broken. The sample sketch attached in Step 6 should work with any 3-phase BLDC, if the variable “motorDelayActual” is set enough large value like 250 or 300. Did you check whether each wire is broken or not? See my reply yesterday.

It is not easy to describe the detail of the calculation in Step 8. However you can get good information in this page. See the first reply for Arduino_Research posted 4 months ago, and search key words or user names in this page.

I watched your video and heard that your BLDC makes a noise in it. I think the last reply for Arduino_Research posted 4 months ago can help you. Search “motorDelayActual” in this page. Also you can find a picture how to check whether your BLDC is broken in earlier comments posted about 3 years ago.

I replied you in Questions in this page. See above.

Hi,If your BLDC motor has 14 poles and 12 slots, it should work in Step 10. Though the driver IC can become very hot sometimes, motor should not become. Check Step 6. If your BLDC rotates with your driver IC in Step 6, wrong wiring or broken gyro is suspected in Step 10.

I get a similar comment yesterday. See the comment of piop and its reply below.

Hi, Click “More Comments” button at the end of this page several times, until the button is not shown. And search with key words bellow.1. Noise Elimination >> "pwm frequency”2. Multi-axis Gimbal >> "your own”All sketches I can provide at present are attached here. See Introduction. Enjoy!

TA7291P is a popular motor driver IC gotten at $1.5 in Japan. Though we can find it at ebay also, we can see various price tags with $1.87 to $11.95. You can use other motor driver or H-bridge instead, if it works with PWM and 3.3-5.0V logic Vcc. Search with “motor driver IC” in web shops like ebay or Google.

詳細な情報ありがとうございます。ご案内の諸点、その通りだと思います。・ジャイロ・センサを2つにすると安定が高まる（センサ出力のノイズやバイアスを緩和できるので）・フローリング床よりカーペット上の方が安定する（極端な話、砂や粘土の上に強く押し付けると、電池なしでも直立します。押したら倒れますが）・電池が弱ると安定性が悪化する（いろいろ試すなら、エネループなどの充電可能な電池の方が割安だと思います）・ジャイロ・モジュールは4つほど買っておくと便利だし安心あと、「 omegaI = omegaI +analogRead(A5) - zeroOmegaI;//NL5 の omegaI の値が静止状態で 2 の値を取る」のは不思議ですね。ジャイロ・センサの出力にはバイアスがあるので、それを zeroOmegaI で評価して引き算でキャンセルしています。ArduinoのA5ピンに何らかのバイアスがあるなら、同ピンをGNDを繋いだプルダウン時の出力で確認できると思います。（zeroOmegaIに2を加えるという対症療法もありますが）なお続編が2つありますのでよろしければご参照ください。

確認が遅れました（MichiK2さんのコメントとともに先ほど通知が届きました）。「delay(xxx);」は「xxxミリ秒処理を停止（待機）しててね」という指示です。xxx＝2500ならば、Arduinoは2.5秒処理停止（待機）します。Arduinoはかなり直観的に扱えますし、丈夫で公開情報も多く多彩な活用ができる上、安価な代替製品も入手可能なのでいろいろ楽しめると思います。

Hi,Pistol Grip Gimbal you say. It works better for a smaller camera such as GoPro. Download the cover picture above and rotate it upside down. You can see that it is near to Pistol Grip. Only the camera attachment cradle must to be set upside down again with the same tilt axis. It requires enough clearance not to interfere with the pan motor on the bottom.

Both two sample sketches in Step 6 could work with every 3-phase BLDC motor. See the eLABZ's commentary in his/her site described in Step 6.If a 3-phase BLDC with no wire broken doesn't rotate with these sketches, it should be doubted that the rotation speed too high. You can change it slower. Constant "motorDelayActual" in these sketches decides it.I think you can get good information by three steps below.1) Click "More Comments" button at the end of page until it is not displayed.2) Search this page for the key word "motorDelayActual".3) Search this page for two key term "it is not easy" and "game123".

Both two sample sketches in Step 6 could work with every 3-phase BLDC motor. See the eLABZ's commentary in her/hissite described in Step 6.If a 3-phase BLDC with no wire broken doesn't rotate with these sketches, it should be doubted that the rotation speed too high. You can change it slower. Constant "motorDelayActual" in these sketches decides it.I think you can get good information by three steps below.1) Click "More Comments" button at the end of page until it is not displayed.2) Search this page for the key word "motorDelayActual".3) Search this page for two key term "it is not easy" and "game123".

Supplement:vonkross, a reader, posted some comments with good figures. One of these figures explains the function "calcPwm()" and some constant variables well. 10 (or 1000) in the name of variables means multiplying the original value to 10 (or 1000) times.

I have gotten several comments like your question ever. See earlier comments and the replies to them*. You can see all of them by clicking “More Comments” button. If you search on this page for some key-word, you could find answers or get good information. (*) For example, Abil FidaA, game123, EricL50 and eggll have posted technical questions and I have replied to them.

I saw your project. I think it might be interesting that the solenoid can move around on the plate of the platform with a small cart. The levitated spoon seems moving autonomously, if the plate is covered.

Hi,The upper picture in Step10 is almost the same as the schematic, though lines omitted. I think you can get the schematic with lines by referring to the picture. If you posted your schematic, we might be able to check it and say something.

Hi,I have gotten many comments for this project. See earlier comments and replies for them. I think you can find what you want to know. Have fun!

Thank you for your comment. I think you could enjoy DIY projects with microprocessor. If your projects require fast image analysis, Arduino cannot work well (Raspberry Pi can work). If not, you can get start your project with Arduino at a lower cost and skill.

I appreciate your thoughtful comment. I see your site of Hackspace in Leicester. It seems very good studio and people look like having so much fun. I would be glad if this article could help you and them. Thank you.

You can make your BLDC rotate. Hence you should not stay at Step6 or 7. I think you should move Step10 and try to get a single axis gimbal with the sample sketch at first. You will be able to know more with reading earlier messages and replies and changing the sample sketch.

Three sample sketches are shown in this article. The first two attached in Step6 could not work well for a gimbal. The last one for a single axis gimbal is attached in Step10.

I saw your comment and video. I think that your code would be similar to the second sample sketch in Step6. To get a good gimbal, I have tried this sketch and abandoned it. See the two videos in Step7; DOCUMENTARY (7) and (8). In these videos the board attached to the top of BLDC motor cannot stay at a point. The board is bigger and heavier than yours. You might see the same situation if you attached a bigger and heavier board to your gimbal. You should try the sample sketch in Step10, which could work well with your BLDC for a single axis gimbal.

Three sample sketches are shown in this article. The first two in Step6 could not work well for a gimbal. The last one for a single axis gimbal is attached in Step10.

Three sample sketches are shown in this article. The first two in Step6 could not work well for a gimbal. The last one for a single axis gimbal is attached in Step10.

In “void loop( )” in the sample sketch in Step10, the degree to rotate BLDC is decided by variable “deg1000” in the first function “chkAndCtl( )”. And the value of “deg1000” decides PWM output as variable “variPwm” in the the second function “calcPwms( )”. The angle of BLDC rotating can be shifted by adding a constant to “deg1000” between these two functions. See below.chkAndCtl( );deg1000 = deg1000 + 12345;calcPwms( );

If your BLDC is the same model shown in Step5 or its successor model, the sample sketch in Step10 ought to work well. It holds rotator of BLDC strongly at a point when three PWM values are kept constant like “217, 0, 255”. If not, breaking of wire in BLDC is suspected. See earlier comments about this topic.

Two sample sketches attached in Step6 could work with any 3 phase BLDC motors. On the other hand, the sample sketch attached in Step10 should be limited to 3 phase BLDC motors with 14-pole/12-slot. Though it could work with many 14-pole/12-slot BLDC motors, it might not work with a special Delta connection. However I have never been told such one. See Step8 and early comments of Ramirez_MecaUPQ and replies which contain pictures.

Yes. See the comments of EricL50 and replies for them posted about 2 years ago. You can know more detail.

Variable deg1000 represents 1000 times of the degree to rotate BLDC. You can find some topics about it in the comments below.

I see your pictures. Neat work. I understand the array of 2 magnets. However I cannot image well how the lower magnet transmits rotational torque to the upper one. I will be grateful if you show video when you make it rotate. Cheers.

Interesting. I image your plan for rotation as below. OK?- Magnet 1 (N----S) :lying on the bottom of globe- Magnet 2 (S----N) :rotating in a horizontal plane in the base unitCan the former rotate more slowly than the latter by something resonate? If not, higher reduction ratio might be required in the latter.

Thank you. I appreciate your suggestion. I get a good alternative.I have looked for topics in web about changing PWM frequency of Due. Then I found a forum aboutit. A very simple way is described in it. It tells that all we should do are simple changes in variant.h in the Arduino library.However I cannot find variant.h in my old IDE or the latest version in web. I have downloaded earlier versions between the former and the latter. At last I found it in IDE 1.6.0 and 1.6.1. Why it cannot be found in the later versions?I felt something disquieting. I stopped and left it for other new projects. I am going to come back to variant.h when these new projects are finished.

Thank you. I appreciate your suggestion. I get a good alternative.I have looked for topics in web about changing PWM frequency of Due. Then I found a forum about it. A very simple way is described in it. It tells that all we should do are simple changes in variant.h in the Arduino library.However I cannot find variant.h in my old IDE or the latest version in web. I have downloaded earlier versions between the former and the latter. At last I found it in IDE 1.6.0 and 1.6.1. Why it cannot be found in the later versions?I felt something disquieting. I stopped and left it for other new projects. I am going to come back to variant.h when these new projects are finished.

Thank you. I appreciate your suggestion. I get a good alternative.I have looked for topics in web about changing PWM frequency of Due. Then I found a forum about it. A very simple way is described in it. It tells that all we should do are simple changes in variant.h in the Arduino library.However I cannot find variant.h in my old IDE or the latest version in web. I have downloaded earlier versions between the former and the latter. At last I found it in IDE 1.6.0 and 1.6.1. Why it cannot be found in the later versions?I felt something disquieting. I stopped and left it for other new projects. I am going to come back to variant.h when these new projects are finished.

Thank you for your good comment. I also have suspected that Arduino Mega with ATmega2560 does not have enough power for my DIY gimbal. Hence I have gotten Arduino Due which has ARM Cortex-M3 CPU in AT91SAM3X8E.I have corrected the original sketch for Mega to work with Due. Though it works well with default PWM frequency, the loud noise is heard. I am searching a good code for Due which can change PWM frequency higher to shift the noise into non-audible range (31kHz) with no trouble.

> Do you use Excel in order to solve a differential equation and test constants values?Yes, I use Excel to get an approximate solution.However I don't intend to explain the detail here, sorry.

1) That's a natural question. Variable “dt” you tell is included implicitly in coefficient “kAngle” in the sample sketch, because it can be thought constant.2) The values of these coefficients are decided finally by trial and error. An equation of motion of the robot or Excel sheet for it is an advanced topic.3) I posted another article to get a self balancing robot where a digital output gyro module, a L3GD20 carrier, is used instead. It is easier to get this module if you are a resident outside Japan.

1) That's a natural question. Variable “dt” you tell is included implicitly in coefficient “kAngle” in the sample sketch, because it can be thought constant.2) The values of these coefficients are decided finally by trial and error. An equation of motion of the robot or Excel sheet for it is an advanced topic.3) I posted another article to another article to get a self balancing robot where a digital output gyro module, a L3GD20 carrier, is used instead. It is easier to get this module if you are a resident outside Japan.

1) That's a natural question. Variable “dt” you tell is included implicitly in coefficient “kAngle” in the sample sketch, because it can be thought constant.2) The values of these coefficients are decided finally by trial and error. An equation of motion of the robot or Excel sheet for it is an advanced topic.3) I posted another article to get a self balancing robot where a digital output gyro module, a L3GD20 carrier, is used instead. It is easier to get this module if you are a resident outside Japan.

1) That's a natural question. Variable “dt” you tell is included implicitly in coefficient “kAngle” in the sample sketch, because it can be thought constant.2) The values of these coefficients are decided finally by trial and error. An equation of motion of the robot or Excel sheet for it is an advanced topic.3) I posted another article to another article to get a self balancing robot where a digital output gyro module, a L3GD20 carrier, is used instead. It is easier to get this module if you are a resident outside Japan.

I have posted the third article to Instructables for advanced reader who has gotten her/his own inverted robot. Though it is written only in Japanese, you can find it in the site of Instructables.You could read it in English using machine translation in web browser. Though I don’t know the performance of translating in Japanese to English, I think Google Chrome is good translating in English to Japanese.Anyway, you can find many interesting projects in the site of Instructables or others. Enjoy!

Now I check voltage supplied by three serially connected AA rechargeable (Ni-MH) batteries. I see 3.8V with no motor connected, and 3.6V with motor turning. I think your motor should get more than 4V when turning at full scale (analogWrite = 255).

I have posted the third article to Instructables for advanced reader who has gotten her/his own inverted robot. Though it is written only in Japanese, you can find it in the site of Instructables.You could read it in English using machine translation in web browser. Though I don’t know the performance of translating in Japanese to English, I think Google Chrome is good translating in English to Japanese.Anyway, you can find many interesting projects in the site of Instructables or others. Enjoy!

Hi,I have received many messages and comments with “I made it!” to Japanese version of this article. Some of them use thicker wheels. On the other side, I have received several messages or comments also with “My robot cannot work well”.Two typical mistakes have been seen in the latter cases: (1) wrong wiring in Step4 and (2) wrong activating for line 76 and 77 in the sample sketch in Step8.The robot with wrong wiring cannot follow your finger in Step6. Hence I think your robot don’t have wrong wiring. And I think you can activate line 76 and 77 in the sample sketch well.I think the output powers of driver IC are too low. At the full power, analogWrite = 255, the IC should supply 5-6V power to DC motor(s). See the top picture in Step4. Four serially connecte...

Hi,I have received many messages and comments with “I made it!” to Japanese version of this article. Some of them use thicker wheels. On the other side, I have received several messages or comments also with “My robot cannot work well”.Two typical mistakes have been seen in the latter cases: (1) wrong wiring in Step4 and (2) wrong activating for line 76 and 77 in the sample sketch in Step8.The robot with wrong wiring cannot follow your finger in Step6. Hence I think your robot don’t have wrong wiring. And I think you can activate line 76 and 77 in the sample sketch well.I think the output powers of driver IC are too low. At the full power, analogWrite = 255, the IC should supply 5-6V power to DC motor(s). See the top picture in Step4. Four serially connected AA batteries supply power to each motor via IC. Even a good robot cannot keep balancing, if the batteries are exhausted.

MPU6050 has a powerful engine called “DMP”. See Step5. It does not seem as simple as described in Introduction. Hence I did not use it in this project.Though you can use it as a simple gyro module without activating DMP, I think you will get a problem. It seems that the protocol for MPU6050 is restricted to I2C, and only two addresses, 0x68 and 0x69, are allowed for MPU6050. A pair of gyro modules is required for each axis in this project. It means that you can make only single axis gimbal if you use a MPU6050 as a simple gyro module.I think you should activate DMP if you use MPU6050. However you have to learn how to use DMP additionally, and I have never used it.

Hi, My DIY 3-axis gimbal is very special for my own development. And its sketch is special, too. However the core of the program of multi-axis gimbal here is not different from the single axis one. See Introduction. All sketches I can provide at present are attached here.

I found a web site for your gyro module, and saw a schematic attached.http://www.ebay.com/itm/Single-axis-Gyroscope-Anal...It seems that “C1” in it works as “C6” in my gyro module. Hence you may have to invalidate “C1”. See Step2.Though I do not know your module well, I think you should connect “VCC”, “GND” and “OUT” in your module to “5V”, “GND” and “A5” in Arduino UNO respectively. However “REF” is connected to none.See the earlier comments and pictures of xgiantsios and my replies to them to know more.

An analog output gyro module is used in this project, though MPU6050 is a digital output module. Another digital output gyro module, L3GD20 carrier, is used in the later version of this project. See “*** …..” in the bottom part of Introduction above.

I cannot understand well what you tell. Sorry. I think you may know more in the later version of this project. See “*** …..” in the bottom part of Introduction above.

Some experiments are shown in Video(2), (3), (4), (6) and (7). In these videos, a red LED is attached on a breadboard. This LED is distinguished from others in the levitating sphere in Step7 and the later.This LED lights depending on the current through the coil for levitation. Hence it lights steadily in steady levitation though it lights unsteadily in unsteady levitation. However it is not needed in the final circuit.

Happy New Year,I think this article would work for making a DIY large DSLR camera gimbal. However it would need several points to be reinforced.(1) Replace BLDC motor(s) with more powerful one.Heat sink(s) might have to be attached to driver IC(s).(2) Build a more rigid frame with aluminum or carbon fiber plates.If you are NOT a very DIY Hobbyist, I think you should buy a suitable gimbal on the market.

I feel that it is not easy to drive servo motor with PID control. See Step 3 and 4 in this article.And I have posted two articles for making a self-balancing robot with a gyro. See my page in Instructables.

No, sorry.

Hi,See the earlier comments of edward.chamberlain and its reply.

Hi,See the earliercomments of edward.chamberlainand its reply.

Hi, See the earlier comments of edward.chamberlainand its reply.

1～2ヶ月前に同様のコメントがあったので、それらの回答をご参照ください。

Only the output of pin 11 changes from ON to OFF with 2-second cycle in your sketch. You can view what it means by seeing eLABZ’s site.Assume that terminal A (red), B (blue) and C (green) of BLDC are connected to pin 9, 10 and 11 in arduino respectively. The slots with red line continue N-(or S-)poles, while the slots with blue line continues S-(or N-)poles. Only the slots with green line change N-poles to S-poles cyclically. It looks like “thin out”.Your BLDC may turn with the sample sketch in Step 6 increasing the value of “motorDelayActual” such as 500 or 1000.

> 回路の間違いがないと判断してもいいでしょうか？何とも言えませんが、そうなのかもしれません。いずれにせよトラブル・シューティングに関しては、これまでのQ&A、および他の方々とのやりとりを参照してください。

タイヤの半径が同程度なら、幅や質量の違いははあまり問題にならないと思います。ステップ8のプログラム修正を行えば、安定性に多少の違いはあれ、自立の気配は感じられるはずです。全く自立の気配がない場合、配線や部品の不良といった工作の問題を疑った方が良いかもしれません。また、ご照会の係数の値については、半月ほど前に同様の質問があったのでそちらを参照してください。、

ステップ2で紹介した参考サイトを見てください。ネットで調べると他にも分かるはずです。

これまでの投稿の内、上手く行かない原因のほぼすべては誤配線だった気がします。デジタル版のステップ6に、動作確認の動画を追加しているので、まずはこの動きを参照してください。その上で、もし意図した方向と逆に車輪が回転するようであれば、（1）モータの配線を逆にする（2つとも）、もしくは（2）スケッチの「analogRead(A5)」の符号を「-」に変える（たぶん2か所）、ことで回転方向を変えられるはずです。

> 重さを変えるとうまく自立しなくなります。プログラムのどこが悪いのですか？重量が増える分には比較的頑健な作りになっていると思います。イントロのデモ・ビデオで、鉄製の工具を2つ載せる所がありますが安定性の悪化は特に認められません。> プログラムの１０〜１２行目の係数のちょうど良い値を見つけるコツとかありますか？この2つの係数の値選択は試行錯誤で決めるのが一番簡単だと思います。

As it is feared that floating point arithmetic needs longer time, Integer is used here. Hence scale-up is needed for some variables to keep good precision. ‘D’ means “deca” by ten times up.