Differences

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--- rgb_dimmer [2015/02/22 19:44] – [Recommended LED module and resistors] breaker27
+++ rgb_dimmer [2023/02/28 14:24] (current) – [Modification of PCB rev. <= 1.1] breaker27
@@ Line 27: / Line 27: @@
 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 43: / 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 66: / Line 78: @@
 If you use this module, the following sets of resistors are recommended:
-^  Placing  ^       Part                  ^   max    ^  bright  ^  normal  ^
+^  Placing  ^       Part                  ^  normal  ^  bright  ^    max   ^
-|    R6     | Resistor for **red** LED    |  7,5 Ohm |   27 Ohm |   39 Ohm |
+|    R6     | Resistor for **red** LED    |   39 Ohm |   27 Ohm |  7,5 Ohm |
-|    R7     | Resistor for **green** LED  |  5,6 Ohm |   18 Ohm |   27 Ohm |
+|    R7     | Resistor for **green** LED  |   27 Ohm |   18 Ohm |  5,6 Ohm |
-|    R8     | Resistor for **blue** LED   |  3,9 Ohm |   15 Ohm |   22 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.
-The "bright" resistors result in LED currents of ~120mA and a power dissipation at the LED module of ~1W and don't need an additional heat sink. The resisors have a power dissipation of <0,3W, 1/4W resistors max be enough.
+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.
-The "normal" resistors are enough if you use a thin glass housing (as shown on the homepage).
-For the "max" resistors, you need an extra heat sink.
+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).
 Use resistors which can tolerate the power they consume. The power is calculated as:
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 with U_Res the voltage at the resistor.
-===== Integrate it into a housing =====
-describe it...