The four pins
GND, VCC, 3000K and 6500K, left to right with the parts up, GND on the square pad. All four are wired: VCC feeds both LEDs, and each colour has a pin of its own that only switches a transistor. The back prints no pin names, so count from the square pad.
Four pins, all of them wired
Most TinkerBlock blocks use three of their four pins. This one uses all four: two for power and one for each colour.
Pick a pin. GND is on the square pad, the only mark that tells four identical holes apart. VCC feeds both LEDs through their resistors, and nothing else. 3000K is the warm white's pin, 6500K the cool white's. Each goes through 1 kΩ into the base of a transistor and nowhere else.
The names are colour temperatures, in kelvin: 3000K is the yellowish white of an old filament bulb, 6500K the bluish white of daylight. The upper LED on the board is the warm one, the lower one the cool one.
Count from the square pad
The back prints TK95 EXTREME BRIGHT DUAL LEDS, a warning and USE PWM TO ADJUST BRIGHTNESS, and no pin names. With the parts facing you and the header at the bottom, the order is GND, VCC, 3000K, 6500K, left to right. From the back it runs the other way, with the square pad on the right.
The header's own pin numbers run the other way too: pin 1 in the design files is 6500K and pin 4 is GND. Wire by the names, never by a number.
What each pin asks of your board
- GND to GND.
- VCC to 5V, or VBUS on a Pico. It never reaches either colour pin, so 5 V is safe on a 3.3 V board.
- 3000K and 6500K to two PWM pins, so each colour can be dimmed on its own. On an Uno that rules out D2, which has no PWM.
When it does not work
Turn the board over: one of the four pads is square, and that is GND. The back prints no pin names. Seen from the front with the parts up and the header at the bottom, GND is the left-hand pin.
The 3000K and 6500K wires are swapped, or the sketch's WARM_PIN and COOL_PIN are. Nothing is harmed: the two channels are the same circuit. Swap the two numbers in the sketch rather than the wires.
No. Many TinkerBlock blocks print NC on one pin, and older wiring notes for this block told you to leave NC unconnected. The TK95 has no NC: all four pins are in a net, and VCC must be wired or nothing lights.
Two LEDs, two transistors, two 10 Ω resistors and two capacitors.
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