Patent Application
20130162975
1. Technical Field
The present disclosure relates to detection systems, especially to a detection system for detecting fan rotation speeds.
2. Description of Related Art
After computers are manufactured, quality tests are required. One of the tests is to detect the rotation speed of the fans of the computers. A conventional method to detect the rotation speed of the fans is using a stroboscope. However, environment light may interfere with the stroboscope, which lowers detection accuracy.
Therefore, there is room for improvement within the art.
Many aspects of the embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean “at least one”.
Referring to
The lighting unit 20 is configured to emit light to fan blades of a fan (not shown). A plurality of light reflecting material is coated on the fan blades. The fan blades reflect light to the light sensing unit 60. The light sensing unit 60 counts according to the reflected light.
Referring to
The light sensing unit 60 includes an opto-electronic coupler 61 and a second resistor R2. The opto-electronic coupler 61 includes a first coupler end and a second coupler end. The first coupler end of the opto-electronic coupler 61 is connected to the second voltage output pin V2. The second coupler end of the opto-electronic coupler 61 is connected to ground via the second resistor R2.
The demodulating unit 70 is connected between the second coupler end of the opto-electronic coupler 61 and the signal input pin I of the control chip 10.
The communication unit 40 is connected to the signal output pin O.
Referring to
The opto-electronic coupler 61 is aligned to the fan blades of the fan. The opto-electronic coupler 61 is turned on when the light-emitting diode 20 emits light and the fan blades reflect light to the opto-electronic coupler 61. A detection signal is transmitted from the opto-electronic coupler 61 to the demodulating unit 70 when the opto-electronic coupler 61 is on. The demodulating unit 70 receives the detection signal when the square wave signal is at a high level. The demodulating unit 70 demodulates the received detection signal to generate a demodulated signal. The demodulated signal is transmitted to the control chip 10 via the signal input pin I. The control chip 10 accounts a rotation speed of the fan according to the demodulated signal. Information about the rotation speed of the fan is transmitted to the computer 50. The computer 50 stores the information and displays the information on a screen of the computer 50.
In the fan rotation speed detection system, the demodulating unit 70 demodulates signals only when the square signal is at a high level, which lowers interference of environment light.
It is to be understood, however, that even though numerous characteristics and advantages of the embodiments have been set forth in the foregoing description, together with details of the structure and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in the matters of shape, size, and arrangement of parts within the principles of the present disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201110443670.7 | Dec 2011 | CN | national |
