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rgb_dimmer [2014/07/12 16:46] – [Integrate it into a housing] breaker27rgb_dimmer [2023/02/28 14:24] (current) – [Modification of PCB rev. <= 1.1] breaker27
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 |    1     | Connector pin header (for serial TX debugging etc.)  | JPx   |  {{ parts:connector_pinheader.jpg }}   | |    1     | Connector pin header (for serial TX debugging etc.)  | JPx   |  {{ parts:connector_pinheader.jpg }}   |
 |    1     | Capacitor 10µF                          | C1         |  {{ parts:capacitor_10uf.jpg }}        | |    1     | Capacitor 10µF                          | C1         |  {{ parts:capacitor_10uf.jpg }}        |
 +|    1     | Capacitor 100µF                         | C2         |  {{ parts:capacitor_100uf.jpg }}       |
 |    1     | IC ATMega328                            | IC1        |  {{ parts:atmega.jpg }}                | |    1     | IC ATMega328                            | IC1        |  {{ parts:atmega.jpg }}                |
 |    1     | Transceiver PCB RFM12B                  | IC2        |  {{ parts:ic_rfm12b.jpg }}             | |    1     | Transceiver PCB RFM12B                  | IC2        |  {{ parts:ic_rfm12b.jpg }}             |
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 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. 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 ===== ===== Buildup of PCB =====
  
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 //(Image directly loaded from external GitHub source. If it doesn't work, fix link in wiki!)// //(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 ===== ===== Flashing the firmware =====
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 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). 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. 
 + 
 +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.
  
-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, you need the following resistors:+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:
  
 +P = U_Res * I_LED
  
-===== Integrate it into a housing =====+with U_Res the voltage at the resistor.
  
-describe it... 
rgb_dimmer.txt · Last modified: 2023/02/28 14:24 by breaker27