Answers.Body: <p>LEGO doesn't make something to directly facilitate this type of integration as far as I know. If you can get a <a href="https://www.lego.com/en-us/product/lego-power-functions-extension-wire-8886" rel="noreferrer">PF extension wire</a>, you could cut it and directly make the connections to your driver circuit.</p>
  <p><a href="https://i.sstatic.net/AW4oG.png" rel="noreferrer"><img src="https://i.sstatic.net/AW4oG.png" alt="PF extension wire" /></a></p>
  <p>You can drive the motor using the middle wires of the PF cable (C1 and C2).</p>
  <p>For what its worth, I would personally prefer an H-bridge such as <a href="https://www.aliexpress.com/item/32925603735.html" rel="noreferrer">this one</a> over a relay as you get faster switching and can use PWM for speed control among other benefits. You'd power a board like that using a 9V supply and connect the C1 and C2 power lines to one of the outputs. Your 5V logic-level signals would connect to one set of inputs to control the motor.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-01-20T22:20:08.383Z
Answers.Text: I'm not that familiar with H-bridges, but I'm researching the option. Can you tell me if [this SparkFun Motor Driver](https://www.sparkfun.com/products/14450) would work just as well as the model you mentioned? (I understand that it may be an H-bridge since it is tagged that way.)
Answers.UserDisplayName: EJ Mak
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-01-21T03:07:10.497Z
Answers.Text: @EJMak I haven't used that exact driver, but it looks like it should do what you want.
Answers.UserDisplayName: jncraton
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-01-09T17:13:04.083Z
Answers.LastActivityDate: 2021-01-09T17:13:04.083Z
Answers.UserDisplayName: jncraton
Body: <p>I’d like to use a signal from a (5V) <a href="https://littleBits.cc" rel="nofollow noreferrer">littleBits</a> circuit to control some (9V) Power Functions motors.</p>
  <p>Does LEGO sell or recommend a DC relay to facilitate this sort of thing?</p>
  <p>If the answer is no, I’d welcome any ideas or experiences in how to do this in a way that’s both easy and LEGO-compatible.</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-01-09T00:00:55.470Z
Comments.Text: <https://secure.sayal.com/STORE2/View_SHOP.php?SKU=248131> is a relay that can be driven from an Arduino, so I would think it could also be driven by littleBits. But it may require more damage to Lego-supplied wires than you'd like, in order to splice it in.
  
  I don't know if it's viable, but could the littleBits circuit move a small arm side to side? If your hand can control the Power Functions using a remote like <https://www.bricklink.com/v2/catalog/catalogitem.page?P=58122c01>, then surely a robotic arm could as well.
  
  I don't know that either of these count as easy, or Lego-compatible.
Comments.UserDisplayName: RSchulz
Tags: <motor><power-functions><electronics><3rd-party>
Title: Does LEGO sell a DC relay for Power Functions?
UserDisplayName: EJ Mak
ThreadText: # Does LEGO sell a DC relay for Power Functions?
  
  (Asked by: username_0 on 2021-01-08)
  
  I’d like to use a signal from a (5V) [littleBits](https://littleBits.cc) circuit to control some (9V) Power Functions motors.
  
  Does LEGO sell or recommend a DC relay to facilitate this sort of thing?
  
  If the answer is no, I’d welcome any ideas or experiences in how to do this in a way that’s both easy and LEGO-compatible.
  
  **Tags:** motor, power-functions, electronics, 3rd-party
  > **Comments:**
  > **username_1**: <https://secure.sayal.com/STORE2/View_SHOP.php?SKU=248131> is a relay that can be driven from an Arduino, so I would think it could also be driven by littleBits. But it may require more damage to Lego-supplied wires than you'd like, in order to splice it in.  I don't know if it's viable, but could the littleBits circuit move a small arm side to side? If your hand can control the Power Functions using a remote like <https://www.bricklink.com/v2/catalog/catalogitem.page?P=58122c01>, then surely a robotic arm could as well.  I don't know that either of these count as easy, or Lego-compatible.  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_2 on 2021-01-09. Score: 5 | Accepted answer
  
  LEGO doesn't make something to directly facilitate this type of integration as far as I know. If you can get a [PF extension wire](https://www.lego.com/en-us/product/lego-power-functions-extension-wire-8886), you could cut it and directly make the connections to your driver circuit.
  
  [![PF extension wire](https://i.sstatic.net/AW4oG.png)](https://i.sstatic.net/AW4oG.png)
  
  You can drive the motor using the middle wires of the PF cable (C1 and C2).
  
  For what its worth, I would personally prefer an H-bridge such as [this one](https://www.aliexpress.com/item/32925603735.html) over a relay as you get faster switching and can use PWM for speed control among other benefits. You'd power a board like that using a 9V supply and connect the C1 and C2 power lines to one of the outputs. Your 5V logic-level signals would connect to one set of inputs to control the motor.
  
  > **Comments:**
  > **username_0**: I'm not that familiar with H-bridges, but I'm researching the option. Can you tell me if [this SparkFun Motor Driver](https://www.sparkfun.com/products/14450) would work just as well as the model you mentioned? (I understand that it may be an H-bridge since it is tagged that way.)  
  > **username_2**: @EJMak I haven't used that exact driver, but it looks like it should do what you want.  
  
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