Answers.Body: <p>I designed some WeDo 2.0 models that can drive and steer using just one motor.
  This one uses a system of gears to alternately drive the left or right wheel of a differential drive robot, depending on the turning direction of the motor.
  <a href="https://i.sstatic.net/04jsE.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/04jsE.png" alt="enter image description here"></a>
  You can find the complete building and programming instructions here:
  <a href="https://robotics.benedettelli.com/lego-wedo2-zigzag/" rel="nofollow noreferrer">https://robotics.benedettelli.com/lego-wedo2-zigzag/</a></p>
  
  <p>Another idea is making a steering vehicle similar to the one shown in the WeDo App, and involves directly driving a pair of wheels, and having two steering wheels that act as a caster with limited swinging movement. That way, when the motor pushes the vehicle forward, the steering wheels are forced to stay straight and the vehicle goes straight; when the motor drives the vehicle backwards, the steering wheels will be free to rotate a bit, and the vehicle will steer.
  <a href="https://i.sstatic.net/eZKL3.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/eZKL3.jpg" alt="enter image description here"></a>
  You can find the complete building and programming instructions here:
  <a href="https://robotics.benedettelli.com/lego-wedo2-car/" rel="nofollow noreferrer">https://robotics.benedettelli.com/lego-wedo2-car/</a></p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2018-10-10T16:26:36.070Z
Answers.Text: Very nice! Thanks for sharing and for taking the time to expand this into a complete answer.
Answers.UserDisplayName: jncraton
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2018-10-04T10:42:53.987Z
Answers.LastActivityDate: 2018-10-10T16:25:30.480Z
Answers.LastEditDate: 2018-10-10T16:25:30.480Z
Answers.UserDisplayName: Daniele Benedettelli
Answers.Body: <p>In WeDo 2.0 app "LEGO® Education WeDo 2.0" there is a complete project <code>12. Steer</code> that is exactly about that</p>
  
  <p>When it drives forward it goes in straight line, when it drives backward it then turns to one side.</p>
  
  <p>There is full build instruction in the app.</p>
  
  <p>I've also added distance sensor and made it fully autonomous - whenever it sees obstacle it goes back, turns, changes direction and continuous driving  </p>
  
  <p><a href="https://i.sstatic.net/zCsky.jpg" rel="noreferrer"><img src="https://i.sstatic.net/zCsky.jpg" alt="enter image description here"></a></p>
  
  <p><a href="https://i.sstatic.net/EN02b.jpg" rel="noreferrer"><img src="https://i.sstatic.net/EN02b.jpg" alt="enter image description here"></a></p>
  
  <p><a href="https://i.sstatic.net/YUlSW.jpg" rel="noreferrer"><img src="https://i.sstatic.net/YUlSW.jpg" alt="enter image description here"></a></p>
  
  <p><a href="https://i.sstatic.net/R9Tef.png" rel="noreferrer"><img src="https://i.sstatic.net/R9Tef.png" alt="enter image description here"></a></p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-01-09T20:36:53.047Z
Answers.LastActivityDate: 2017-01-09T20:36:53.047Z
Answers.UserDisplayName: Kamil Dziedzic
Answers.Body: <p>This can be done without a caster wheel as well:</p>
  
  <p>Start out with a three wheeled vehicle, with two wheels in the front and one smaller wheel with less traction than the front wheels in the back. All wheels need to be fixed.</p>
  
  <p>One of the front wheels is attached to the motor. This might need to have some gearing to get an appropriate speed.<br>
  The other front wheel is unpowered but can only rotate forward by adding a <a href="http://www.marksimonson.com/assets/content/notebook/legotypedetailB_1.JPG" rel="noreferrer">ratchet</a>:  </p>
  
  <p><a href="https://i.sstatic.net/4E7Ch.jpg" rel="noreferrer"><img src="https://i.sstatic.net/4E7Ch.jpg" alt="foto"></a></p>
  
  <p>The back wheel is unpowered.</p>
  
  <p>Driving forward the vehicle will more or less move straight, guided by the rear wheel.<br>
  Driving backwards the ratchet will engage, stopping one wheel. The vehicle will now turn.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2016-02-23T11:32:01.167Z
Answers.Text: This is even better idea than the caster wheel, since I can change the turning degree (by rolling back shorter or longer periods of time)... thanks!
Answers.UserDisplayName: Alexander Farber
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2016-02-23T11:28:49.200Z
Answers.LastActivityDate: 2016-02-24T07:55:18.407Z
Answers.LastEditDate: 2016-02-24T07:55:18.407Z
Answers.UserDisplayName: Aaganrmu
Body: <p>In WeDo 2.0 set <strong>there is only 1 motor</strong>, which can be remotely switched on and off by using the iPad app (by writing a Scratch program). </p>
  
  <p>Also motor rotating direction can be toggled remotely.</p>
  
  <p><a href="https://i.sstatic.net/ESRKv.jpg" rel="noreferrer"><img src="https://i.sstatic.net/ESRKv.jpg" alt="WeDo foto"></a></p>
  
  <p>As an inexperienced LEGO builder I wonder if it is possible to <strong>build a remote-controlled vehicle out of 280 WeDo 2.0 pieces, which would be steered by changing the motor rotation direction</strong>.</p>
  
  <p><a href="https://i.sstatic.net/jrF3t.jpg" rel="noreferrer"><img src="https://i.sstatic.net/jrF3t.jpg" alt="280 WeDo parts"></a></p>
  
  <p>I am thinking of having 2 wheels with wide tires in front the vehicle, connected to the motor.</p>
  
  <p>And having a single <em>caster wheel</em> with narrow tire at the back of the vehicle, not connected to the motor.</p>
  
  <p>The <em>caster wheel</em> would roll straight, when the vehicle drives forwards.</p>
  
  <p>But when driving backwards, it would snap to a certain angle.</p>
  
  <p><strong>UPDATE 3:</strong></p>
  
  <p>Found a picture for such a <em>caster wheel</em> in the <a href="https://www.nostarch.com/technic_wheels.htm" rel="noreferrer">LEGO Technic Idea Book</a> by Mr. Yoshihito Isogawa:</p>
  
  <p><a href="https://i.sstatic.net/5ps7H.png" rel="noreferrer"><img src="https://i.sstatic.net/5ps7H.png" alt="foto"></a></p>
  
  <p><strong>UPDATE:</strong></p>
  
  <p>I have followed Aaganrmu's suggestion (thank you) and have tried to build a simple vehicle using <em>ratchet</em> instead of <em>caster wheel</em>:</p>
  
  <p><a href="https://www.youtube.com/watch?v=uqYQ79SdBpY" rel="noreferrer">https://www.youtube.com/watch?v=uqYQ79SdBpY</a></p>
  
  <p>Unfortunately, it doesn't work well. There is too much friction - on the axles of all 3 wheels and on the rubber band.</p>
  
  <p>I wonder if experienced LEGO builders can propose a better vehicle out of <a href="http://brickset.com/sets/45300-1/WeDo-2-0-Core-Set" rel="noreferrer">WeDo 2.0 parts</a> than mine:</p>
  
  <p><a href="https://i.sstatic.net/h7KYk.jpg" rel="noreferrer"><img src="https://i.sstatic.net/h7KYk.jpg" alt="pic 1"></a></p>
  
  <p><a href="https://i.sstatic.net/ePo6o.jpg" rel="noreferrer"><img src="https://i.sstatic.net/ePo6o.jpg" alt="pic 2"></a></p>
  
  <p><a href="https://i.sstatic.net/jYjaN.jpg" rel="noreferrer"><img src="https://i.sstatic.net/jYjaN.jpg" alt="pic 3"></a></p>
  
  <p><a href="https://i.sstatic.net/oATqp.jpg" rel="noreferrer"><img src="https://i.sstatic.net/oATqp.jpg" alt="pic 4"></a></p>
  
  <p><a href="https://i.sstatic.net/kRJKS.jpg" rel="noreferrer"><img src="https://i.sstatic.net/kRJKS.jpg" alt="pic 5"></a></p>
  
  <p>And I feel that my Scratch program can be improved too, since it is not very responsive to user input (when touching the 4 green arrows):</p>
  
  <p><a href="https://i.sstatic.net/ecz1W.jpg" rel="noreferrer"><img src="https://i.sstatic.net/ecz1W.jpg" alt="enter image description here"></a></p>
  
  <p><strong>UPDATE 2:</strong> Got a nice suggestion at <a href="http://www.eurobricks.com/forum/index.php?showtopic=122172" rel="noreferrer">Eurobricks forum</a>:</p>
  
  <p><a href="https://www.youtube.com/watch?v=rq7PJwbmDSc" rel="noreferrer"><img src="https://i.sstatic.net/YgjAa.png" alt="enter image description here"></a></p>
  
  <p>(video authored by Mr. Yoshihito Isogawa again).</p>
  
  <p><strong>UPDATE 4:</strong></p>
  
  <p>Here a good WeDo 2.0 model with steering:</p>
  
  <p><a href="https://www.youtube.com/watch?v=Q9sd4MxW4YY" rel="noreferrer">https://www.youtube.com/watch?v=Q9sd4MxW4YY</a></p>
  
Tags: <motor><remote-control><vehicle><steering><wedo>
Title: How to build a steerable remote-controlled vehicle with just 1 motor?
UserDisplayName: Alexander Farber
ThreadText: # How to build a steerable remote-controlled vehicle with just 1 motor?
  
  (Asked by: username_0 on 2016-02-22)
  
  In WeDo 2.0 set **there is only 1 motor**, which can be remotely switched on and off by using the iPad app (by writing a Scratch program).
  
  Also motor rotating direction can be toggled remotely.
  
  [![WeDo foto](https://i.sstatic.net/ESRKv.jpg)](https://i.sstatic.net/ESRKv.jpg)
  
  As an inexperienced LEGO builder I wonder if it is possible to **build a remote-controlled vehicle out of 280 WeDo 2.0 pieces, which would be steered by changing the motor rotation direction**.
  
  [![280 WeDo parts](https://i.sstatic.net/jrF3t.jpg)](https://i.sstatic.net/jrF3t.jpg)
  
  I am thinking of having 2 wheels with wide tires in front the vehicle, connected to the motor.
  
  And having a single *caster wheel* with narrow tire at the back of the vehicle, not connected to the motor.
  
  The *caster wheel* would roll straight, when the vehicle drives forwards.
  
  But when driving backwards, it would snap to a certain angle.
  
  **UPDATE 3:**
  
  Found a picture for such a *caster wheel* in the [LEGO Technic Idea Book](https://www.nostarch.com/technic_wheels.htm) by Mr. Yoshihito Isogawa:
  
  [![foto](https://i.sstatic.net/5ps7H.png)](https://i.sstatic.net/5ps7H.png)
  
  **UPDATE:**
  
  I have followed username_4's suggestion (thank you) and have tried to build a simple vehicle using *ratchet* instead of *caster wheel*:
  
  <https://www.youtube.com/watch?v=uqYQ79SdBpY>
  
  Unfortunately, it doesn't work well. There is too much friction - on the axles of all 3 wheels and on the rubber band.
  
  I wonder if experienced LEGO builders can propose a better vehicle out of [WeDo 2.0 parts](http://brickset.com/sets/45300-1/WeDo-2-0-Core-Set) than mine:
  
  [![pic 1](https://i.sstatic.net/h7KYk.jpg)](https://i.sstatic.net/h7KYk.jpg)
  
  [![pic 2](https://i.sstatic.net/ePo6o.jpg)](https://i.sstatic.net/ePo6o.jpg)
  
  [![pic 3](https://i.sstatic.net/jYjaN.jpg)](https://i.sstatic.net/jYjaN.jpg)
  
  [![pic 4](https://i.sstatic.net/oATqp.jpg)](https://i.sstatic.net/oATqp.jpg)
  
  [![pic 5](https://i.sstatic.net/kRJKS.jpg)](https://i.sstatic.net/kRJKS.jpg)
  
  And I feel that my Scratch program can be improved too, since it is not very responsive to user input (when touching the 4 green arrows):
  
  [![enter image description here](https://i.sstatic.net/ecz1W.jpg)](https://i.sstatic.net/ecz1W.jpg)
  
  **UPDATE 2:** Got a nice suggestion at [Eurobricks forum](http://www.eurobricks.com/forum/index.php?showtopic=122172):
  
  [![enter image description here](https://i.sstatic.net/YgjAa.png)](https://www.youtube.com/watch?v=rq7PJwbmDSc)
  
  (video authored by Mr. Yoshihito Isogawa again).
  
  **UPDATE 4:**
  
  Here a good WeDo 2.0 model with steering:
  
  <https://www.youtube.com/watch?v=Q9sd4MxW4YY>
  
  **Tags:** motor, remote-control, vehicle, steering, wedo
  
  
  ---
  
  ## 3 answers
  
  ### Answer by username_4 on 2016-02-23. Score: 13 | Accepted answer
  
  This can be done without a caster wheel as well:
  
  Start out with a three wheeled vehicle, with two wheels in the front and one smaller wheel with less traction than the front wheels in the back. All wheels need to be fixed.
  
  One of the front wheels is attached to the motor. This might need to have some gearing to get an appropriate speed.  
  The other front wheel is unpowered but can only rotate forward by adding a [ratchet](http://www.marksimonson.com/assets/content/notebook/legotypedetailB_1.JPG):
  
  [![foto](https://i.sstatic.net/4E7Ch.jpg)](https://i.sstatic.net/4E7Ch.jpg)
  
  The back wheel is unpowered.
  
  Driving forward the vehicle will more or less move straight, guided by the rear wheel.  
  Driving backwards the ratchet will engage, stopping one wheel. The vehicle will now turn.
  
  > **Comments:**
  > **username_0**: This is even better idea than the caster wheel, since I can change the turning degree (by rolling back shorter or longer periods of time)... thanks!  
  
  ---
  
  ### Answer by username_3 on 2017-01-09. Score: 6
  
  In WeDo 2.0 app "LEGO® Education WeDo 2.0" there is a complete project `12. Steer` that is exactly about that
  
  When it drives forward it goes in straight line, when it drives backward it then turns to one side.
  
  There is full build instruction in the app.
  
  I've also added distance sensor and made it fully autonomous - whenever it sees obstacle it goes back, turns, changes direction and continuous driving
  
  [![enter image description here](https://i.sstatic.net/zCsky.jpg)](https://i.sstatic.net/zCsky.jpg)
  
  [![enter image description here](https://i.sstatic.net/EN02b.jpg)](https://i.sstatic.net/EN02b.jpg)
  
  [![enter image description here](https://i.sstatic.net/YUlSW.jpg)](https://i.sstatic.net/YUlSW.jpg)
  
  [![enter image description here](https://i.sstatic.net/R9Tef.png)](https://i.sstatic.net/R9Tef.png)
  
  
  ---
  
  ### Answer by username_1 on 2018-10-04. Score: 4
  
  I designed some WeDo 2.0 models that can drive and steer using just one motor.
  This one uses a system of gears to alternately drive the left or right wheel of a differential drive robot, depending on the turning direction of the motor.
  [![enter image description here](https://i.sstatic.net/04jsE.png)](https://i.sstatic.net/04jsE.png)
  You can find the complete building and programming instructions here:
  <https://robotics.username_1.com/lego-wedo2-zigzag/>
  
  Another idea is making a steering vehicle similar to the one shown in the WeDo App, and involves directly driving a pair of wheels, and having two steering wheels that act as a caster with limited swinging movement. That way, when the motor pushes the vehicle forward, the steering wheels are forced to stay straight and the vehicle goes straight; when the motor drives the vehicle backwards, the steering wheels will be free to rotate a bit, and the vehicle will steer.
  [![enter image description here](https://i.sstatic.net/eZKL3.jpg)](https://i.sstatic.net/eZKL3.jpg)
  You can find the complete building and programming instructions here:
  <https://robotics.username_1.com/lego-wedo2-car/>
  
  > **Comments:**
  > **username_2**: Very nice! Thanks for sharing and for taking the time to expand this into a complete answer.  
  
  ---
  
  