ekamresh/tscircuit_test_pcb

index.circuit.tsx

PCB

Schematic

import React from "react"

// ---------------------------------------------------------------------------
// Heart-shaped 555 timer LED blinker  -  "Happy Valentines Day Mahija!"
// ---------------------------------------------------------------------------
// Power:    2 x CR2032 in series (6V) on the BACK of the board, soft-power
//           via a tactile pushbutton.  CR2032s give ~30 mA continuous which
//           is exactly what we need.
//
// Circuit:  Classic NE555 astable multivibrator
//   f  = 1.44 / ((Ra + 2*Rb) * C)
//   Ra = 4.7k, Rb = 47k, C = 10uF  ->  ~1.46 Hz, ~52% duty cycle
//
// LEDs:     14 x 5 mm through-hole red LEDs around the heart border, all
//           wired in parallel through ONE shared 56 ohm 0805 current-limit
//           resistor.  At 6V supply with the 555 sourcing ~45 mA, each LED
//           sees ~3 mA average -> bright enough for an indoor display
//           without taxing the chip or the cells.
// ---------------------------------------------------------------------------

// --- Heart-shaped board outline -------------------------------------------
// Parametric heart curve (Eugene Beutel, 1909):
//   x(t) = 16 sin^3(t)
//   y(t) = 13 cos(t) - 5 cos(2t) - 2 cos(3t) - cos(4t)
const HEART_SCALE = 2.5 // mm per unit  ->  ~80 mm wide x ~72 mm tall
const HEART_Y_OFFSET = 2 // shift up so the centroid sits near (0,0)
const HEART_OUTLINE = Array.from({ length: 96 }, (_, i) => {
  const t = (i / 96) * Math.PI * 2
  const x = 16 * Math.sin(t) ** 3
  const y =
    13 * Math.cos(t) -
    5 * Math.cos(2 * t) -
    2 * Math.cos(3 * t) -
    Math.cos(4 * t)
  return { x: x * HEART_SCALE, y: y * HEART_SCALE + HEART_Y_OFFSET }
})

// --- LED ring positions ----------------------------------------------------
// 14 hand-picked t-values, mirrored across the y-axis.  They sweep both
// lobes from upper-shoulder down past the bottom point, but skip:
//   - the cleavage (small t) where the heart curve dips inward, and
//   - the very bottom point (t near pi) where there is no room.
const LED_INSET = 0.85
const LED_TS = [
  0.65, 0.96, 1.27, 1.58, 1.88, 2.19, 2.5,
  3.783, 4.093, 4.403, 4.703, 5.013, 5.323, 5.633,
]
const LED_POSITIONS = LED_TS.map((t) => {
  const x = 16 * Math.sin(t) ** 3
  const y =
    13 * Math.cos(t) -
    5 * Math.cos(2 * t) -
    2 * Math.cos(3 * t) -
    Math.cos(4 * t)
  return {
    x: x * HEART_SCALE * LED_INSET,
    y: y * HEART_SCALE * LED_INSET + HEART_Y_OFFSET,
  }
})
const NUM_LEDS = LED_POSITIONS.length

// 5 mm through-hole LED footprint: 2.54 mm lead pitch, 1 mm plated holes
const LED_TH_FOOTPRINT = "led_tht_p2.54mm_pw1mm_ph1mm"

// --- Battery holder footprint ---------------------------------------------
// Custom footprint approximating a horizontal dual-CR2032 holder
// (e.g. Keystone 1042 / MPD BC-2032-2).  The two cells sit side-by-side
// inside a plastic body about 50 mm x 22 mm; the cells are wired in series
// internally, so the PCB only sees a +6 V terminal and a GND terminal at
// the far ends of the body.  We mount it on the BACK of the board so the
// front face stays clean for the silkscreen love note.
const DualCoinCellFootprint = (
  <footprint>
    {/* + terminal (positive end of cell 1) */}
    <smtpad
      pcbX={-22}
      pcbY={0}
      shape="rect"
      width={3}
      height={6}
      portHints={["1", "pos", "BAT_POS"]}
    />
    {/* GND terminal (negative end of cell 2) */}
    <smtpad
      pcbX={22}
      pcbY={0}
      shape="rect"
      width={3}
      height={6}
      portHints={["2", "neg", "BAT_NEG"]}
    />
    {/* Silkscreen outline of the two coin cells.  No courtyard rect: the
        holder lives on the BACK of the board, alone, so it cannot collide
        with anything on the front. */}
    <silkscreencircle pcbX={-12} pcbY={0} radius={11} />
    <silkscreencircle pcbX={12} pcbY={0} radius={11} />
  </footprint>
)

export default () => (
  <board
    outline={HEART_OUTLINE}
    solderMaskColor="purple"
    silkscreenColor="white"
    layers={2}
  >
    {/* ----------------------------------------------------------------- */}
    {/* NE555 timer (SOIC-8)                                              */}
    {/* ----------------------------------------------------------------- */}
    <chip
      name="U1"
      footprint="soic8"
      manufacturerPartNumber="NE555DR"
      pinLabels={{
        pin1: "GND",
        pin2: "TRIG",
        pin3: "OUT",
        pin4: "RESET",
        pin5: "CTRL",
        pin6: "THRES",
        pin7: "DISCH",
        pin8: "VCC",
      }}
      pinAttributes={{
        VCC: { requiresPower: true },
        GND: { requiresGround: true },
        RESET: { mustBeConnected: true },
      }}
      pcbX={0}
      pcbY={0}
      schX={0}
      schY={0}
    />

    {/* ----------------------------------------------------------------- */}
    {/* 555 timing network                                                */}
    {/*   Ra (R_A) : VCC   -> DISCH                                       */}
    {/*   Rb (R_B) : DISCH -> THRES (= TRIG)                              */}
    {/*   Ct       : THRES -> GND                                         */}
    {/* ----------------------------------------------------------------- */}
    <resistor
      name="R_A"
      resistance="4.7k"
      footprint="0805"
      pcbX={-9}
      pcbY={7}
      schX={-4}
      schY={4}
    />
    <resistor
      name="R_B"
      resistance="47k"
      footprint="0805"
      pcbX={-9}
      pcbY={3}
      schX={-4}
      schY={2}
    />
    <capacitor
      name="C_T"
      capacitance="10uF"
      footprint="0805"
      pcbX={-9}
      pcbY={-1}
      schX={-4}
      schY={0}
    />

    {/* CTRL pin bypass capacitor (datasheet recommended) */}
    <capacitor
      name="C_CTRL"
      capacitance="10nF"
      footprint="0805"
      pcbX={8}
      pcbY={-2}
      schX={4}
      schY={0}
    />

    {/* VCC decoupling capacitor right next to pin 8 */}
    <capacitor
      name="C_VCC"
      capacitance="100nF"
      footprint="0805"
      pcbX={8}
      pcbY={5}
      schX={4}
      schY={4}
    />

    {/* ----------------------------------------------------------------- */}
    {/* Single shared LED current-limit resistor                          */}
    {/*   OUT -> R_LED -> LED_ANODE rail (drives all 14 LEDs in parallel) */}
    {/*                                                                   */}
    {/*   Vsupply  = 6 V (2x CR2032)                                      */}
    {/*   V_OH(loaded) ~ 4.5 V at 50 mA out                               */}
    {/*   V_LED    ~ 2.0 V (red, low current)                             */}
    {/*   I_total  = (4.5 - 2.0) / 56  ~  45 mA                           */}
    {/*   Per LED  ~ 3.2 mA average -> nicely visible indoors             */}
    {/* ----------------------------------------------------------------- */}
    <resistor
      name="R_LED"
      resistance="56"
      footprint="0805"
      pcbX={0}
      pcbY={-7}
      schX={2}
      schY={-4}
    />

    {/* ----------------------------------------------------------------- */}
    {/* LED ring  -  14 x 5 mm THT red LEDs, all anodes commoned to       */}
    {/* LED_ANODE rail and all cathodes to GND.                           */}
    {/* ----------------------------------------------------------------- */}
    {LED_POSITIONS.map((p, i) => {
      const idx = i + 1
      return (
        <led
          key={idx}
          name={`LED${idx}`}
          color="red"
          footprint={LED_TH_FOOTPRINT}
          pcbX={p.x}
          pcbY={p.y}
          schX={6 + ((idx - 1) % 5) * 3}
          schY={-2 - Math.floor((idx - 1) / 5) * 3}
        />
      )
    })}

    {/* ----------------------------------------------------------------- */}
    {/* Power: 2x CR2032 in series (6 V) on the BACK of the board         */}
    {/* ----------------------------------------------------------------- */}
    <battery
      name="BAT1"
      voltage="6V"
      capacity="225mAh"
      footprint={DualCoinCellFootprint}
      layer="bottom"
      pcbX={0}
      pcbY={-2}
      schX={-10}
      schY={6}
    />

    {/* ----------------------------------------------------------------- */}
    {/* Power switch.  Tactile pushbutton at the top of the heart -       */}
    {/* press to blink (or solder a wire across pins 1-3 for "always on", */}
    {/* or replace with a slide switch for latching power).               */}
    {/* ----------------------------------------------------------------- */}
    <pushbutton
      name="SW1"
      footprint="pushbutton"
      pcbX={0}
      pcbY={10}
      schX={-6}
      schY={6}
    />

    {/* ----------------------------------------------------------------- */}
    {/* Silkscreen love note                                              */}
    {/* ----------------------------------------------------------------- */}
    <silkscreentext
      text="Happy Valentines Day Mahija!"
      fontSize={2}
      pcbX={0}
      pcbY={-22}
    />

    {/* ================================================================= */}
    {/* Connectivity                                                      */}
    {/* ================================================================= */}

    {/* --- Power rails ------------------------------------------------- */}
    {/* Battery + -> switch -> VCC rail.  Battery - -> GND rail.          */}
    {/* Pushbutton has 4 pads: pin1+pin2 are one terminal, pin3+pin4 the  */}
    {/* other.  Tie both pads on each side.                               */}
    <trace from=".BAT1 > .pin1" to=".SW1 > .pin1" />
    <trace from=".BAT1 > .pin1" to=".SW1 > .pin2" />
    <trace from=".SW1 > .pin3" to="net.VCC" />
    <trace from=".SW1 > .pin4" to="net.VCC" />
    <trace from=".BAT1 > .pin2" to="net.GND" />

    {/* --- 555 power and reset ----------------------------------------- */}
    <trace from=".U1 > .VCC" to="net.VCC" />
    <trace from=".U1 > .GND" to="net.GND" />
    <trace from=".U1 > .RESET" to="net.VCC" />

    {/* --- Decoupling -------------------------------------------------- */}
    <trace from=".C_VCC > .pin1" to="net.VCC" />
    <trace from=".C_VCC > .pin2" to="net.GND" />
    <trace from=".C_CTRL > .pin1" to=".U1 > .CTRL" />
    <trace from=".C_CTRL > .pin2" to="net.GND" />

    {/* --- Astable timing network -------------------------------------- */}
    <trace from=".R_A > .pin1" to="net.VCC" />
    <trace from=".R_A > .pin2" to=".U1 > .DISCH" />
    <trace from=".R_B > .pin1" to=".U1 > .DISCH" />
    <trace from=".R_B > .pin2" to=".U1 > .THRES" />
    <trace from=".U1 > .THRES" to=".U1 > .TRIG" />
    <trace from=".C_T > .pin1" to=".U1 > .THRES" />
    <trace from=".C_T > .pin2" to="net.GND" />

    {/* --- Single shared current-limit resistor ------------------------ */}
    <trace from=".U1 > .OUT" to=".R_LED > .pin1" />
    <trace from=".R_LED > .pin2" to="net.LED_ANODE" />

    {/* --- LED ring : all anodes -> LED_ANODE, all cathodes -> GND ----- */}
    {LED_POSITIONS.map((_, i) => {
      const idx = i + 1
      return (
        <React.Fragment key={`net-${idx}`}>
          <trace from={`.LED${idx} > .pin1`} to="net.LED_ANODE" />
          <trace from={`.LED${idx} > .pin2`} to="net.GND" />
        </React.Fragment>
      )
    })}
  </board>
)