Update README.md

codelast · codelast · commit ef6b2ceb25c3 · 2016-06-01T23:19:08.000+08:00
diff --git a/gpio/stepper-motor/README.md b/gpio/stepper-motor/README.md
@@ -3,3 +3,5 @@ Demos on how to control a stepper motor through the GPIO ports on Raspberry Pi.
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 该目录下的程序演示了如何通过树莓派的GPIO接口控制步进电机。
+
+![](https://raw.githubusercontent.com/codelast/raspberry-pi/master/gpio/stepper-motor/demo/stepper-motor.png)
