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--- leds [2015/08/14 08:21]
janhenrik [How to properly solder the LED's]
+++ leds [2015/08/26 10:28]
starblue
@@ Line 11: / Line 11: @@
 These are RGB LEDs with their own microcontroller, so all LEDs can be programmed individually. They are daisy chained, first the two in the lower area of the PCB and then six on the antenna on the top. So if you don't want to add all LEDs, or want to start with only one first, you have to follow the order "//middle left, middle right, antenna from right to left//" or bridge the data pins of the unused LED pads.
-:!: **Important note** :!: Due to a fn0rd in the layout the transistors intended to control power of the LEDs can't be used as intended. The transistor pads have not been populated. You either have to
+:!: **Important note** :!: Due to a fn0rd in the layout the transistors intended to control power of the LEDs can't be used as intended. The transistor pads have not been populated. There are several ways of getting the LEDs to work:
-  - build some complex SMD sculpture using wires or
+  - build some complex SMD sculpture using wires (more about this at the bottom of the page)
-  - simply bridge 3 of these pads. But then your badge will always be powered, even if turned off, so either:
+  - build a working high-side switch [[starblue led power|using two MOSFETs]] to get the functionality that was originally intended (or optionally to switch LED power with a GPIO port)
-    - try to use a jumper or
+  - try to use a jumper/switch to bridge two of the transistor pads
-    - try to use a switch to bridge the transistor pads (with some wires one switch can be used for all three) or
+  - bridge two of the transistor pads with solder
-    - always disconnect the battery to turn the badge off.
-Example with all possible LEDs and bridges (for power supply) soldered (LEDs green, bridges red):
+The last option has the disadvantage that the blue LED will be a bit dimmer but it is the easiest option and the LEDs are quite bright already.
+There are spaces for capacitors which are recommended, but the LEDs usually work fine without.
+**Do not bridge all three pads of each transistor as this will create a short!**
+Example with all possible LEDs and correct bridges on two of the three transistor pins (for power supply) soldered (LEDs green, bridges red):
 {{ :led3.png?100 |}}
@@ Line 25: / Line 30: @@
 Sorry for that, but wouldn't it be boring otherwise? :-P
+== Which way around do the LEDs go?
+If you have a close look at an LED, you'll notice one corner is marked by having a bit cut off.
+In the photo below, the pads where this corner needs to be are marked in red:
+{{::leds.png?200|}}
+== I soldered one LED but it doesn't work?
+All LEDs are on the same data line, if they are not all soldered on, the data line is interrupted. You can either solder on all LEDs or bridge the data line. The image below shows where the data line goes, red lines are on the PCB, green lines are usually closed by LEDs. If you are not filling all LED spots, you have to fill the missing connections with wire.
+{{::leds-data.png?200|}}
+== Will the LEDs do something as soon as I switch the rad1o on?
+no.
+Switch off your badge, press the joystick to the left (in the direction of DARC). Select TESTAPP, and then ws2812b.
+> How should the test pattern look like?
+The 2 lower LEDs should be yellow, the one at the tip of the antenna should be green and the other 5 LEDs on the antenna blue.
 == How to properly solder the LED's
@@ Line 33: / Line 60: @@
 __Why?__
-Wires: when you solder bridges onto the transistor pads ( like explained earlier ) the processor will be always on, draining some power. With the wires not.
+Wires: If you solder bridges onto the transistor pads (as explained earlier), the LEDs will be supplied with 3.3 V and not the recommended >4.5 V. With the wires there will be roughly 3.5 V to 4.3 V supplied to the LEDs, which is closer to their specification.
-Capacitors: The WS2812B LED's are very vulnerable to not having a 100nF capacitor soldered next to their power pins, the internal controller pulses the LED's ( PWM ), so the current conversion is also very pulsed. That will cause voltage spikes on the ground ( Yes ground ) line, which will destroy the controller/the LED.
+Capacitors: The WS2812B LED's are very vulnerable to not having a 100nF capacitor soldered next to their power pins, the internal controller pulses the LED's (PWM), so the current conversion is also very pulsed. That can cause voltage spikes on the ground (Yes, ground) line, which could destroy the controller/the LED.
-LED's: Why you ask, LED's are fancy \o/
+LED's: Why do you ask? LED's are fancy \o/
 __What you will need:__
-  * Thin isolated wire ( 0.2 mm enamelled copper wire [ Kupferlackdraht ] works fine )
+  * Thin isolated wire (0.2 mm enamelled copper wire [ Kupferlackdraht ] works fine)
   * 8 100nF SMD capacitors
   * 8 WS2812B LED's
@@ Line 50: / Line 77: @@
 Add the thin wire to the solder pads like in the picture below.
-{{:img_20150814_075501.jpg|}}
+{{:img_20150814_075501.jpg?800|}}
-{{:img_20150814_075511.jpg|}}
+{{:img_20150814_075511.jpg?800|}}
-{{:img_20150814_075519.jpg|}}
+{{:img_20150814_075519.jpg?800|}}
@@ Line 59: / Line 86: @@
 Add the LED's.
-( scroll down for an explaining picture )
+( scroll up for an explaining picture [ [[https://rad1o.badge.events.ccc.de/leds#which_way_around_do_the_leds_go|Or click me]] ] )
 __Step 3__
@@ Line 65: / Line 93: @@
 Now you should add the capacitors, that is kind of hard to do, because three capacitors don't have solder pads.
-{{:img_20150814_075501.jpg|}}
+{{:img_20150814_075501_01.jpg?800|}}
-{{:img_20150814_075401.jpg|}}
-{{:img_20150814_075430.jpg|}}
-{{:img_20150814_075422.jpg|}}
-I hope that the pictures are clear enough, the has to be a 100nF capacitor next to the power pins of every LED.
+You can see the new capacitors next to the upper left LED pins.
+{{:img_20150814_075401.jpg?800|}}
+{{:img_20150814_075430.jpg?800|}}
+{{:img_20150814_075422.jpg?800|}}
+I hope that the pictures are clear enough, there has to be a 100nF capacitor next to the power pins of every LED.
 __Step 4__
@@ Line 76: / Line 107: @@
 Test it.
-{{:bagde_bright.jpg|}}
+{{:bagde_bright.jpg?400|}}
-{{:bagde_dark.jpg|}}
+{{:bagde_dark.jpg?400|}}
 Yay \o/
-(Now successful running for 1 1/2 days)
-== Which way around do the LEDs go?
-If you have a close look at an LED, you'll notice one corner is marked by having a bit cut off.
-In the photo below, the pads where this corner needs to be are marked in red:
-{{::leds.png?200|}}
-== I soldered one LED but it doesn't work?
-All LEDs are on the same data line, if they are not all soldered on, the data line is interrupted. You can either solder on all LEDs or bridge the data line. The image below shows where the data line goes, red lines are on the PCB, green lines are usually closed by LEDs. If you are not filling all LED spots, you have to fill the missing connections with wire.
-{{::leds-data.png?200|}}
-== Will the LEDs do something as soon as I switch the rad1o on?
-no.
-Switch off your badge, press the joystick to the left (in the direction of DARC). Select TESTAPP, and then ws2812b.
-> How should the test pattern look like?
-The 2 lower LEDs should be yellow, the one at the tip of the antenna should be green and the other 5 LEDs on the antenna blue.

rad1o

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