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Table of Contents
Building up an RGB Dimmer
Needed Parts and PCB
You need a PCB. You may use the layout from Github and etch it yourself / let it be produced at a factory creating PCBs.
Partlist (in buildup order)
| Amount | Part | Placing | Picture |
|---|---|---|---|
| 1 | PCB Controller |  |
|
| 1 | Diode 1N4148 | D1 |  |
| 3 | Zener Diode 3,3V | D2, D3, D4 |  |
| 1 | Resistor 1k5 brown-green-red | R1 |  |
| 4 | Resistor 560R green-blue-brown | R2, R9, R11, R12 |  |
| 1 | Resistor 47k XXXXXXXXXXXXXXXXX | R3 |  |
| 3 | Resistor 1k brown-black-red | R4, R5, R6 |  |
| 1 | Resistor 4k7 yellow-violet-red | R7 |  |
| 1 | Resistor 1M brown-black-green | R10 |  |
| 1 | Resistor 3R9 XXXXXXXXXXXXXXXXX | R16 |  |
| 1 | Resistor 10k XXXXXXXXXXXXXXXXX | R17, R19 |  |
| 1 | Quarz / Crystal 20 MHz | Q1 |  |
| 2 | Capacitor 22pF | C1, C2 |  |
| 1 | Button/Switch | S1 |  |
| 1 | IC holder | IC1 |  |
| 1 | Voltage regulator LP2950Z | IC3 |  |
| 1 | LED 2mA | LED1 |  |
| 1 | Connector AVR ISP 6pin | JP1 |  |
| 2 | Capacitor 10µF | C5, C6 |  |
| 1 | IC ATMega328 | IC1 |  |
| 1 | Transceiver PCB RFM12B | IC2 |  |
| 1 | Antenna (82,2mm wire) | JP2 |  |
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
As always: start from flat to high. Go through the partlist and solder the parts from the top ones to the last ones.
For some parts, you have to consider something special:
- IC holder: Look at the notch and place it in the right direction.
- LED: Solder it to a wire if you want to place the PCB in a housing later. Read the instructions on how to solder the LED to a cable. The longer wire of the LED is +. It goes into the hole more in the middle of the PCB.
- ISP Connector: The notch points to the side of the PCB.
- 10 uF Capacitor: The marked line is -, which points to the mid of the PCB. On the PCB, + is labelled.
- ATMega: Before inserting it, you may want to check the voltage levels when switching the power on. Pin7 should have VCC (3V) against pin8 (ground). If you have different voltages: don't panic, nothing is broken, nothing is fried. Search your error. To insert the ATMega, bend the pins at 90 degreed by placing the ATMega on the table and bending it carefully. Then insert it into the IC holder. Be sure that you are not charged with electricity (ESD!) when touching the IC pins.
- RFM12B: You should also check the voltages first before soldering the module. At the place for the radio module the pad beside the antenna and at the opposite side the third pad should read about 3.3 V. For soldering, read the RFM12B mounting instructions.
(Image directly loaded from external GitHub source. If it doesn't work, fix link in wiki!)