RGB LED Mood Lighting
Ambience courtesy of an MSP430
Published in issue 374, February 2008
High-brightness LEDs are being used more and more widely in lighting applications. Here we present a simple ‘mood light’ using just a few components. Each of three LEDs is provided with a constant current using a switching regulator, and brightness control is performed by an MSP430 microcontroller generating three PWM signals. The printed circuit board could be fitted inside a table lamp with a frosted glass envelope or could be used with an LED spotlight for indirect lighting.
Resistors
(SMD 0603 unless otherwise stated)
R2 = 330Ω
R3,R4,R6 = 100kΩ
R5 = 47kΩ
R11,R13,R21,R23,R31,R33 = 10kΩ
R12,R22,R32 = 2Ω (SMD 1206)
Capacitors
C1,C11,C13,C21,C23,C31,C33 = 4µF7 6.3V; X5R, (SMD 0603)
C2 = 100nF (SMD 0603)
C3 = 10nF (SMD 0603)
C4,C12,C22,C32 = 22μF (SMD1210)
Semiconductors
D1 = BZX84-C3V3 (SMD SOT23)
D13,D23,D33 = TS4148 RY (SMD 0805)
D14 = 1W LED, Golden Dragon, red (Osram)*
D23 = 1W LED, Golden Dragon, green (Osram)*
D33 = = 1W LED, Golden Dragon, blue (Osram)*
U1 = MSP430F2131RGB (TI)
U11,U21,U31 = TPS62260DRV SMD SON-6 (TI)
Inductors
L11,L21,L31 = 2μH2, 1.1 A, 110 mΩ, SMD 2x2.5 mm (MIPSA2520D2R2, FDK)
Miscellaneous
R1 = rotary encoder, Bourns 3315-001
JP1 = 14-way boxheader
JP2 = 6-way connector (Samtec TMS-106-XX-X-S-RA)
TP11,TP12,TP13,TP21,TP22,TP23,TP31,TP32,TP33 = test pin, e.g. Keystone 5001
Heatsink, Fischer SK 477 100
Heat conducting self-adhesive tape, Fischer WLFT 404 R25
PCB, order code 070892-2**
*LED alternatives:
Lumiled REBEL LED using PCB 070892-1 Osram Golden Dragon LED using PCB 070892-2
CREE XLAMP LED using PCB 070892-3
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Click below to download a PDF copy of this article from Elektor magazine. Please note. In view of the complexity of international markets, Elektor cannot guarantee the availability of components for this project.
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