Differences

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--- rgb_dimmer [2014/08/23 17:45] – [Partlist (in buildup order)] breaker27
+++ rgb_dimmer [2023/02/28 14:24] (current) – [Modification of PCB rev. <= 1.1] breaker27
@@ Line 25: / Line 25: @@
 You have to decide on the LEDs you want to use. Depending on the type, you have to use different resistors R6, R7, R8 for the LEDs. See further down for a recommended one.
+The capacitor C2 is only to buffer the input voltage in case you connect LEDs that draw much power and you want to avoid problems with some programmers that may have problems flahing when the voltage changes much.
 ===== Buildup of PCB =====
@@ Line 41: / Line 44: @@
 //(Image directly loaded from external GitHub source. If it doesn't work, fix link in wiki!)//
+===== Modification of PCB rev. <= 1.1 and SW rev >= 0.13.0 =====
+The older PCBs have the speaker connected to PD3 (pin5). Since the 16 bit timer has to be used to generate accurate frequencies, you have to connect it instead to PB1 (pin 15). The pin to drive the transistor for the blue LED has to be moved from PB1 (pin 15) to PD3 (pin 5).
+In future PCB versions, this shall be changed in the schematic and layout.
+To perform the modification, cut the PCB tracks on the marked positions and connect them to the other pins with patch cables.
+{{ rgb_dimmer_speaker_mod.jpg }}
 ===== Flashing the firmware =====
@@ Line 58: / Line 72: @@
 with U_in the input voltage of the device (e.g. 5V), U_LED the voltage your LED needs (e.g. 2.8V) and I_LED the current you want to do through the LED (e.g. 250mA).
-==== Recommended LED module ====
+==== Recommended LED module and resistors ====
+One LED type that is very bright with a moderate current are the **Cree XP-E LEDs**. They are available as a module in the smarthomatic shop. The module makes assembling easier and ensures good cooling.
+If you use this module, the following sets of resistors are recommended:
+^  Placing  ^       Part                  ^  normal  ^  bright  ^    max   ^
+|    R6     | Resistor for **red** LED    |   39 Ohm |   27 Ohm |  7,5 Ohm |
+|    R7     | Resistor for **green** LED  |   27 Ohm |   18 Ohm |  5,6 Ohm |
+|    R8     | Resistor for **blue** LED   |   22 Ohm |   15 Ohm |  3,9 Ohm |
+The "normal" resistors are enough if you use a thin glass housing (as shown on the homepage). You can use normal 1/4 W resistors and the LED module won't heat up much. No heat sink required. This is the safest and easiest choice.
-One LED type that is very bright with a moderate current are the Cree XP-E LEDs. They are available as a module in the smarthomatic shop. The module makes assembling easier and ensures good cooling.
+The "bright" resistors result in LED currents of ~120mA and a power dissipation at the LED module of ~1W. It should not need an additional heat sink, but it gets hot already (you can touch it, maybe ~50°C). The resisors have a calculated power dissipation of ~0,3W. 1/4W resistors max be enough, but I recommend to use metal oxyde resistors (1W). The overall current of the RGB dimmer is 380mA, so a typical power supply for smartphones with 500mA max. current fits perfectly.
-If you use this module, the following resistors are recommended:
-^  Amount  ^               Part                        ^  Placing   ^             Picture                    ^
+With the "max" resistors, you definitely need an extra heat sink at the LED module and resistors which can cope with the higher current (1W).
-|    1     | Resistor 7R5 violet-green-black-silver (red LED)   | R6   |  {{ parts:resistor_560r.jpg }}         |
-|    1     | Resistor 5R6 green-blue-black-silver (green LED)   | R7   |  {{ parts:resistor_560r.jpg }}         |
-|    1     | Resistor 3R9 orange-white-black-silver (blue LED)  | R8   |  {{ parts:resistor_560r.jpg }}         |
 Use resistors which can tolerate the power they consume. The power is calculated as:
@@ Line 74: / Line 95: @@
 with U_Res the voltage at the resistor.
-===== Integrate it into a housing =====
-describe it...