/* * receiver.ino -- UART -> two LEGO Powered Up hubs (ESP32 "B") * * Model: Johnny 5 (Short Circuit) MOC, 7 motors across 2 Technic hubs. * * Board package: esp32 (the normal Espressif one), core 2.0.17 * Libraries: Legoino + NimBLE-Arduino 1.4.x (both via Library Manager) * * Core 3.x will not build Legoino - you get 'std::string does not name a type' * and a ReadUInt32LE declaration mismatch. Stay on 2.0.17 for this board. * * Listens for gamepad frames from the Bluepad32 board on Serial2 and drives * both hubs over BLE using Legoino. This board must NOT have the Bluepad32 * board package selected - keeping BTstack and NimBLE on separate chips is * the entire reason there are two boards. * * Wiring to the transmitter board: * RX GPIO16 <- TX GPIO17 on transmitter * TX GPIO17 -> RX GPIO16 on transmitter * GND -> GND (mandatory - common ground) * * Control scheme is tank drive: every input drives exactly one motor. * * FILE ORDER MATTERS: * The Arduino IDE injects generated function prototypes immediately before * the FIRST function definition in the file. Any type used in a function * signature must be declared above that point - which is why HubLink, * PortState and Frame all live in the types block. Move a function above * them and you get "'Frame' has not been declared". * * Created by: Jess Rogerson (yelling commands at Claude.AI) */ #include "Lpf2Hub.h" // ---------------------------------------------------------------- settings // Hub BLE addresses. Run tools/hub_scanner to find them - do not guess. // // hub 0 - lower body hub 1 - upper body // A right track A head tilt // B left track B head turn // D body lift C left arm // D right arm static const char *HUB0_ADDR = "90:84:2b:61:f2:d7"; static const char *HUB1_ADDR = "90:84:2b:61:e6:8c"; // Port numbers are just bytes in the LEGO protocol, same on every hub type. static const byte PORT_A = 0x00; static const byte PORT_B = 0x01; static const byte PORT_C = 0x02; static const byte PORT_D = 0x03; // Technic / Control+ motors are tacho motors -> leave this at 1. // Plain train motors and the simple Powered Up motors -> set it to 0. #define USE_TACHO_MOTORS 1 // Set to 1 to log every motor command that goes out. Useful for proving which // port a command actually lands on. Noisy - turn it back off afterwards. #define DEBUG_MOTORS 0 static const int DEADZONE = 40; // raw stick counts ignored around centre // Motor directions. Flip to -1 if an axis runs backwards - mirrored mountings // are normal on a symmetric model, and this is cheaper than editing signs // scattered through applyFrame(). static const int DIR_LEFT_TRACK = 1; static const int DIR_RIGHT_TRACK = -1; static const int DIR_BODY_LIFT = 1; static const int DIR_HEAD_TILT = 1; static const int DIR_HEAD_TURN = 1; static const int DIR_LEFT_ARM = 1; static const int DIR_RIGHT_ARM = 1; // Per-axis power caps. Everything except the tracks runs into a mechanical end // stop and there is no position feedback, so holding a direction at a stop // stalls the motor. Lower these if an axis feels forceful. static const int TRACK_MAX = 100; // LEGO speed range is -100..100 static const int HEAD_MAX = 45; static const int LIFT_MAX = 60; static const int ARM_MAX = 45; // Track scaling: normal, L1 held (precision), R1 held (full). static const int SCALE_NORMAL = 75; static const int SCALE_PRECISION = 40; static const int SCALE_FULL = 100; // Bluepad32 button masks. Verify against your own pad with DEBUG_BUTTONS in // the transmitter sketch if any of these seem wrong. static const unsigned BTN_A = 0x0001; // Cross static const unsigned BTN_B = 0x0002; // Circle static const unsigned BTN_X = 0x0004; // Square static const unsigned BTN_Y = 0x0008; // Triangle static const unsigned BTN_L1 = 0x0010; static const unsigned BTN_R1 = 0x0020; static const unsigned DPAD_U = 0x01; static const unsigned DPAD_D = 0x02; static const unsigned DPAD_R = 0x04; static const unsigned DPAD_L = 0x08; static const unsigned long MOTOR_MIN_GAP_MS = 100; // per port static const unsigned long HUB_MIN_GAP_MS = 25; // per hub, ~40 cmd/sec static const unsigned long LINK_TIMEOUT_MS = 400; // failsafe static const unsigned long RECONNECT_GAP_MS = 2000; static const int LINK_RX_PIN = 16; static const int LINK_TX_PIN = 17; static const long LINK_BAUD = 115200; static const int STATUS_LED_PIN = 2; // =================================================================== types struct HubLink { Lpf2Hub hub; const char *addr; const char *label; bool initialised; unsigned long retryAt; unsigned long lastCmdAt; // per-hub rate limit, shared across its ports }; struct PortState { int lastSpeed; unsigned long lastSentAt; }; struct Frame { int lx, ly, rx, ry; unsigned buttons, dpad; int l2, r2; }; // ================================================================= globals static HubLink gHubs[2] = { {Lpf2Hub(), HUB0_ADDR, "hub0", false, 0, 0}, {Lpf2Hub(), HUB1_ADDR, "hub1", false, 0, 0}, }; // Indexes: 0 rightTrack, 1 leftTrack, 2 bodyLift, // 3 headTilt, 4 headTurn, 5 leftArm, 6 rightArm static PortState gPort[7] = {{999, 0}, {999, 0}, {999, 0}, {999, 0}, {999, 0}, {999, 0}, {999, 0}}; static unsigned long lastFrameAt = 0; static bool failsafeEngaged = true; // ================================================================= helpers // Deadzone, then rescale so the remaining travel still reaches full speed. static int stickToSpeed(int raw, int maxSpeed) { if (raw > -DEADZONE && raw < DEADZONE) return 0; int sign = (raw < 0) ? -1 : 1; long magnitude = labs((long)raw) - DEADZONE; long scaled = (magnitude * maxSpeed) / (512L - DEADZONE); if (scaled > maxSpeed) scaled = maxSpeed; return sign * (int)scaled; } static void driveMotor(HubLink &hl, byte port, int speed, PortState &st) { if (!hl.hub.isConnected()) return; unsigned long now = millis(); bool stopping = (speed == 0 && st.lastSpeed != 0); // Stops always go out immediately. Everything else is rate limited twice: // per port, and per hub - hub 1 has four motors on it, and the per-port // limit alone lets through more than the hub will swallow. if (!stopping) { if (speed == st.lastSpeed) return; if ((now - st.lastSentAt) < MOTOR_MIN_GAP_MS) return; if ((now - hl.lastCmdAt) < HUB_MIN_GAP_MS) return; } #if DEBUG_MOTORS Serial.printf("TX %s port %u speed %d\n", hl.label, port, speed); #endif #if USE_TACHO_MOTORS hl.hub.setTachoMotorSpeed(port, speed); #else hl.hub.setBasicMotorSpeed(port, speed); #endif st.lastSpeed = speed; st.lastSentAt = now; hl.lastCmdAt = now; } static void stopEverything() { driveMotor(gHubs[0], PORT_A, 0, gPort[0]); driveMotor(gHubs[0], PORT_B, 0, gPort[1]); driveMotor(gHubs[0], PORT_D, 0, gPort[2]); driveMotor(gHubs[1], PORT_A, 0, gPort[3]); driveMotor(gHubs[1], PORT_B, 0, gPort[4]); driveMotor(gHubs[1], PORT_C, 0, gPort[5]); driveMotor(gHubs[1], PORT_D, 0, gPort[6]); } // Connect the hubs one at a time. Kicking off two scans at once upsets the // shared NimBLE scanner and you end up with one hub connected and one sulking. static void serviceHub(HubLink &hl) { if (hl.hub.isConnected()) return; if (hl.hub.isConnecting()) { hl.hub.connectHub(); if (hl.hub.isConnected()) { Serial.printf("[%s] connected (%s)\n", hl.label, hl.addr); hl.hub.setLedColor(GREEN); } else { Serial.printf("[%s] connect failed, retrying\n", hl.label); hl.initialised = false; hl.retryAt = millis() + RECONNECT_GAP_MS; } return; } if (!hl.initialised && millis() >= hl.retryAt) { Serial.printf("[%s] scanning for %s\n", hl.label, hl.addr); hl.hub.init(std::string(hl.addr)); hl.initialised = true; } } static uint8_t xorChecksum(const char *s, size_t len) { uint8_t c = 0; for (size_t i = 0; i < len; i++) c ^= (uint8_t)s[i]; return c; } static bool parseFrame(char *line, Frame &f) { char *star = strrchr(line, '*'); if (!star) return false; *star = '\0'; unsigned expected = 0; if (sscanf(star + 1, "%2x", &expected) != 1) return false; if (xorChecksum(line, strlen(line)) != (uint8_t)expected) return false; return sscanf(line, "G,%d,%d,%d,%d,%u,%u,%d,%d", &f.lx, &f.ly, &f.rx, &f.ry, &f.buttons, &f.dpad, &f.l2, &f.r2) == 8; } // Tank drive. One input per motor - nothing is mixed. static void applyFrame(const Frame &f) { // Both shoulders together is the panic stop. if ((f.buttons & BTN_L1) && (f.buttons & BTN_R1)) { stopEverything(); return; } int scale = SCALE_NORMAL; if (f.buttons & BTN_L1) scale = SCALE_PRECISION; if (f.buttons & BTN_R1) scale = SCALE_FULL; int leftTrack = stickToSpeed(-f.ly, TRACK_MAX) * scale / 100 * DIR_LEFT_TRACK; int rightTrack = stickToSpeed(-f.ry, TRACK_MAX) * scale / 100 * DIR_RIGHT_TRACK; int headTilt = ((f.dpad & DPAD_U) ? HEAD_MAX : (f.dpad & DPAD_D) ? -HEAD_MAX : 0) * DIR_HEAD_TILT; int headTurn = ((f.dpad & DPAD_R) ? HEAD_MAX : (f.dpad & DPAD_L) ? -HEAD_MAX : 0) * DIR_HEAD_TURN; // R2 raises, L2 lowers. Both analog 0..1023, so the lift stays proportional. int bodyLift = constrain((f.r2 - f.l2) * LIFT_MAX / 1023, -LIFT_MAX, LIFT_MAX) * DIR_BODY_LIFT; // Square raises the left arm, Circle lowers it. int leftArm = ((f.buttons & BTN_X) ? ARM_MAX : (f.buttons & BTN_B) ? -ARM_MAX : 0) * DIR_LEFT_ARM; // Cross raises the right arm, Triangle lowers it. int rightArm = ((f.buttons & BTN_A) ? ARM_MAX : (f.buttons & BTN_Y) ? -ARM_MAX : 0) * DIR_RIGHT_ARM; driveMotor(gHubs[0], PORT_A, rightTrack, gPort[0]); driveMotor(gHubs[0], PORT_B, leftTrack, gPort[1]); driveMotor(gHubs[0], PORT_D, bodyLift, gPort[2]); driveMotor(gHubs[1], PORT_A, headTilt, gPort[3]); driveMotor(gHubs[1], PORT_B, headTurn, gPort[4]); driveMotor(gHubs[1], PORT_C, leftArm, gPort[5]); driveMotor(gHubs[1], PORT_D, rightArm, gPort[6]); } // ==================================================================== main void setup() { Serial.begin(115200); Serial2.begin(LINK_BAUD, SERIAL_8N1, LINK_RX_PIN, LINK_TX_PIN); pinMode(STATUS_LED_PIN, OUTPUT); digitalWrite(STATUS_LED_PIN, LOW); Serial.println("LEGO hub receiver starting"); } void loop() { // 1. Keep the hubs connected, hub0 first. serviceHub(gHubs[0]); if (gHubs[0].hub.isConnected()) serviceHub(gHubs[1]); bool ready = gHubs[0].hub.isConnected() && gHubs[1].hub.isConnected(); digitalWrite(STATUS_LED_PIN, ready ? HIGH : LOW); // 2. Pull whole lines off the link. static char buf[128]; static size_t idx = 0; while (Serial2.available()) { char c = (char)Serial2.read(); if (c == '\r') continue; if (c == '\n') { buf[idx] = '\0'; Frame f; if (idx > 0 && parseFrame(buf, f)) { lastFrameAt = millis(); failsafeEngaged = false; applyFrame(f); } idx = 0; } else if (idx < sizeof(buf) - 1) { buf[idx++] = c; } else { idx = 0; // overrun, throw the line away } } // 3. Failsafe - link went quiet, stop before something drives off a table. if (!failsafeEngaged && (millis() - lastFrameAt) > LINK_TIMEOUT_MS) { Serial.println("Link timeout - stopping motors"); stopEverything(); failsafeEngaged = true; } }