Differences

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--- embedded:adventures:dualpower [2016/09/25 13:23] – pvela
+++ embedded:adventures:dualpower [2024/08/20 21:38] (current) – external edit 127.0.0.1
@@ Line 22: / Line 22: @@
 ==== mBed Implementation for RC Servomotors ====
-In this example, an opto-isolator is needed because the mBed uses 3.3V as the logic and also does not provide the current needed to drive a motor.  The servomotor here is an RC servomotor which uses a supply in the 4-6V range. Nromally, we use a P2501 opt-isolator, however in this case the students used a different chip, the MCT6.
+In this example, an opto-isolator is needed because the mBed uses 3.3V as the logic and also does not provide the current needed to drive a motor.  The servomotor here is an RC servomotor which uses a supply in the 4-6V range. Normally, we use a P2501 opt-isolator, however in this case the students used a different chip, the MCT6.
 We found [[http://www.farnell.com/datasheets/1866419.pdf|this MCT6 datasheet]] to be helpful. The MCT6 chip contains 2 optoisolators. Here is how to connect the first one:
-. Connect your output wire from the mBed to pin 1.
+  - Connect your output wire from the mBed to pin 1.
-. Connect pin 2 to mBed ground with a small valued (1k) resistor.
+  - Connect pin 2 to mBed ground with a small valued (1k) resistor.
-. Connect pin 7 to external DC ground with a large resistor (10k).
+  - Connect pin 7 to external DC ground with a large resistor (10k).
-. Connect pin 8 to external DC Vcc and to the input signal wire of whatever you need to control.
+  - Connect pin 8 to external DC Vcc and to the input signal wire of whatever you need to control.
+In this described configuration, the right hand side appears to be operating in pull-up mode.
+;#;
+{{:embedded:adventures:optoisolator_mBed_RCservo.jpg?500|}}
+;#;
+;#;
+Figure 1: The MCT6 optoisolators used in a circuit.
+;#;
-{{:embedded:adventures:img_2055.jpg?200|}}
+The image is a bit messy due to the wires being everywhere, but it should be somewhat clear that the second, smaller proto-board has an opto-isolator on it.  It is acting as the bridge between the mBed side and the RC servomotor side. The blue wire at pin 8 of the MCT6 ultimately connects to the second (signal) pin of the servomotor.  The first and third (right-most) wires and pins are the power and ground. It looks to be that the third pin is ground.
+---------------
-Figure 1: The MCT6 optoisolators used in a circuit.
+;#;
+[[ Basics:Adventures | Main]]
+;#;