LedDevices < Embedded_Systems

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---+ LEDs

5 out of the 37 sensors are some sort of LEDS:

First we have the standard LEDs (not part of the sensor kit)
| <img alt="led.png" height="346" src="%ATTACHURL%/led.png" title="led.png" width="313" /> |  <img alt="leds.png" height="352" src="%ATTACHURL%/leds.png" title="leds.png" width="207" />  |  <p><img alt="ledschematics.png" height="350" src="%ATTACHURL%/ledschematics.png" title="ledschematics.png" width="159" /></p> <p> </p>  |
As you can see from the photo LEDs have leads with different length, the longer one being the anode and must therefore be connected to the + pole. The current through the LED must be limited to some tens of mA, which means that we need a resistor (typically 330 <font face="Liberation Serif, serif">&#x2126;</font><font face="Liberation Serif, serif"> if the LED is powered with 3.3 V) </font>as shown in the circuit diagram.
---++ 2 colored LEDs

The sensor kit has 5 LED circuits which feature multi-color LEDs. First there are 2 color LEDs with exactly the same functionality but different LED sizes.
| <img alt="2colorLEDs.png" height="332" src="%ATTACHURL%/2colorLEDs.png" title="2colorLEDs.png" width="358" /> | <img alt="2colLedschematic.png" height="339" src="%ATTACHURL%/2colLedschematic.png" title="2colLedschematic.png" width="275" /> |
We need a 330<font face="Liberation Serif, serif">&#x2126;</font><font face="Liberation Serif, serif"> resistor from the “-” pin to ground. The “S” pin lights the green </font><font face="Liberation Serif, serif">diode</font><font face="Liberation Serif, serif">, </font><font face="Liberation Serif, serif">while</font><font face="Liberation Serif, serif">the middle pin lights the red </font><font face="Liberation Serif, serif">diode</font><font face="Liberation Serif, serif">.</font>

In addition to the 2 colored LED there is a tiny red SMD LED with its associate current limiting resistor. This can be activated<br />through pin 2 (+) and pin 3 (S, now “-”, note that S is the “+” pin when accessing the 2-colored LED)
---++ rgb LEDs

Again we have 2 circuit boards with essentially the same functionality.
| <img alt="3colLed-1.png" height="260" src="%ATTACHURL%/3colLed-1.png" title="3colLed-1.png" width="377" /> | <img alt="3colLed-2.png" height="264" src="%ATTACHURL%/3colLed-2.png" title="3colLed-2.png" width="312" /> |
|  <img alt="rgbSMDschematic.png" height="389" src="%ATTACHURL%/rgbSMDschematic.png" title="rgbSMDschematic.png" width="268" />  |  <img alt="rgdLEDschematic.png" height="370" src="%ATTACHURL%/rgdLEDschematic.png" title="rgdLEDschematic.png" width="222" />  |
However, the rgb LED with the standard LED shape has 1k<font face="Liberation Serif, serif">&#x2126;</font><font face="Liberation Serif, serif"> current limiting resistors already installed on the PCB while the surface mount (flat) LED does not.<br /></font>%RED%<font face="Liberation Serif, serif"><b>So … be careful!</b></font>%ENDCOLOR%
---++ The flashing colored LED

%BLACK%<font face="Liberation Serif, serif">This LED automatically cycles through different colors and flashes. It is connected like the simple LED. In addition to the flashing colored LED there is the IR (infra red)<br />transmitter which is hardly distinguishable from the flashing LED. The plastic bag containing the PCB however is clearly marked.</font>%ENDCOLOR%
| <img alt="flashingLED.png" height="340" src="%ATTACHURL%/flashingLED.png" title="flashingLED.png" width="273" /> | <img alt="flashSchematic.png" height="454" src="%ATTACHURL%/flashSchematic.png" title="flashSchematic.png" width="216" /> | <p>Not to be confused with this -&gt;</p> <p> </p> | <img alt="IREmit.png" height="349" src="%ATTACHURL%/IREmit.png" title="IREmit.png" width="277" /> |
---+ The Laser

In contrast to the LEDs the laser can be directly connected to 3.3V.
| <img alt="laser.png" height="234" src="%ATTACHURL%/laser.png" title="laser.png" width="387" /> | <img alt="laserSchematic.png" height="339" src="%ATTACHURL%/laserSchematic.png" title="laserSchematic.png" width="171" /> |

-- %USERSIG{UliRaich - 2017-01-03}%

---++ Comments

%COMMENT%

Attachments

Topic attachments
I	Attachment	History	Action	Size	Date	Who	Comment
png	2colLedschematic.png	r1	manage	11.4 K	2017-01-03 - 20:24	UnknownUser	2 colored LED schematic
png	2colorLEDs.png	r1	manage	980.4 K	2017-01-03 - 20:45	UnknownUser	2 colored LEDs
png	3colLed-1.png	r1	manage	495.1 K	2017-01-03 - 20:52	UnknownUser	SMD rgb LED
png	3colLed-2.png	r1	manage	581.9 K	2017-01-03 - 20:52	UnknownUser	rdb LED
png	IREmit.png	r1	manage	1104.6 K	2017-01-03 - 21:02	UnknownUser	IR transmitter
png	flashSchematic.png	r1	manage	6.9 K	2017-01-03 - 20:24	UnknownUser	flash LED schematic
png	flashingLED.png	r1	manage	2292.9 K	2017-01-03 - 21:03	UnknownUser	flash LED
png	laser.png	r1	manage	414.1 K	2017-01-03 - 21:02	UnknownUser	laser
png	laserSchematic.png	r1	manage	6.7 K	2017-01-03 - 21:09	UnknownUser	laser schematic
png	led.png	r1	manage	51.1 K	2017-01-03 - 20:28	UnknownUser	LED explanation
png	leds.png	r1	manage	2950.7 K	2017-01-03 - 20:10	UnknownUser	standard LEDs
png	ledschematics.png	r1	manage	7.2 K	2017-01-03 - 20:28	UnknownUser	LED schematics
png	rgbSMDschematic.png	r1	manage	7.6 K	2017-01-03 - 20:24	UnknownUser	SMD rgb LED schematic
png	rgdLEDschematic.png	r1	manage	9.8 K	2017-01-03 - 20:25	UnknownUser	rgb LED schematic

Topic revision: r1 - 2017-01-03 - uli