Hi. I'm struggling to understand why a Feather M0 controlled Halloween prop I've been making occasionally stops working at the point in a switch() structure where a pneumatic valve should be activated. When a trigger pulse is detected, the Feather turns on a light in the coffin and triggers an MP3 board to start playing spooky sounds. The Feather then switches a linear actuator (via an electromechanical power and a direction relay) to open the coffin lid. After a limit switch detects that the coffin lid is fully open, the Feather turns off the two linear actuator relays and applies power to the pneumatic valve to make the zombie pop out (... and say some spooky stuff, pop back into his coffin, and the coffin lid closes). This all typically works fine about 80% of the time, but the rest of the time the program hangs up at (or shortly before) the same point where the pneumatic valve should be activated. I've tested my limit switches. I'm beginning to wonder if a disruptive inductive fly-back voltage spike is being generated when the linear actuator, or its power and direction relays, are turned off. As a precaution I staggered the relay switching times by 50 ms to avoid concurrent changes. In addition to the routine diode across the relay coils, I also put a simple snubber circuit (a 43 ohm resistor in series with a 0.01 uF capacitor) across the linear actuator motor. As far as I can tell, these precautions have had no effect. While I continue to suspect a hardware-based problem, I'd appreciate a sanity check as to whether there's something I'm not understanding about my code which might interfere with the sketch getting to the "sc_Extend" case where it normally would turn on the pneumatic valve. Any advice about my code or suggestions for diagnosing and fixing the root cause would be greatly appreciated! #define OpeningLightSoundPeriod 5000 // Pre-opening sound period in ms #define ExtraLidMovementTime 3000 // Extra time (ms) to make sure lid fully opens/closes #define PostTalkingPauseTime 4000 // Time (ms) for zombie to chill after saying his piece #define PostLidClosurePauseTime 2000 // Time (ms) from lid closure to light & sound off #define PostLightOffPauseTime 5000 // Time (ms) from light off to sound off after lid closure #define RUNstop 0 #define OPENclose 1 #define WaveLight 5 #define EXTENDretract 6 #define LidOpen 9 #define LidClosed 10 #define Trigger 11 #define Extended 12 #define Retracted 17 // Formerly 13 #define Mp3Trigger 14 // FN-BC10 Level Hold Loop Playback (Mode 1). Hold trigger pin low for playback duration #define HdMp3Busy 15 #define CofMp3Busy 16 const byte sc_AwaitingTrigger = 1; // If triggered, turn on WaveLight & lower CofMp3 trigger (sound begins) const byte sc_StartOpeningLid = 2; // Wait 5 sec before opening coffin lid const byte sc_FinishOpeningLid = 3; // If OPEN limit switch = HIGH, start 3 sec extra movement timer const byte sc_Extend = 4; // Disable lid actuator. Turn on PValve (zombie begins to rise) const byte sc_HdMp3Busy = 5; // Wait until HdMp3 is LOW (busy, zombie starts talking) const byte sc_HdMp3NotBusy = 6; // Wait until HdMp3 is HIGH (not busy, zombie stops talking) const byte sc_StartRetracting = 7; // Wait 4 sec then turn off PValve (begin to retract) const byte sc_StartClosingLid = 8; // If RETRACTED limit switch is HIGH, start closing lid const byte sc_LidClosed = 9; // If CLOSED limit switch is HIGH, start 2 sec post closure timer const byte sc_LightOff = 10; // Turn off WaveLight then start 5 sec post light timer const byte sc_SoundOff = 11; // Raise CofMp3 trigger (coffin sound off). Loop back to await next trigger byte CoffinStepNo = sc_AwaitingTrigger; unsigned long MillisMoment; void setup() { pinMode(RUNstop, OUTPUT); pinMode(OPENclose, OUTPUT); pinMode(WaveLight, OUTPUT); pinMode(EXTENDretract, OUTPUT); pinMode(LidOpen, INPUT_PULLUP); pinMode(LidClosed, INPUT_PULLUP); pinMode(Trigger, INPUT_PULLUP); pinMode(Extended,INPUT_PULLUP); pinMode(Retracted, INPUT_PULLUP); pinMode(Mp3Trigger, OUTPUT); pinMode(HdMp3Busy, INPUT); // Active low pinMode(CofMp3Busy, INPUT); // Active low digitalWrite(RUNstop, LOW); // Initialize output levels digitalWrite(OPENclose, LOW); digitalWrite(WaveLight, LOW); digitalWrite(EXTENDretract, LOW); digitalWrite(Mp3Trigger, HIGH); // put your setup code here, to run once: } void loop() { switch (CoffinStepNo) { case sc_AwaitingTrigger: if(digitalRead(Trigger) == HIGH) { digitalWrite(WaveLight, HIGH); // Turn on Wave Light digitalWrite(Mp3Trigger, LOW); // Initiate falling edge of MP3 board trigger MillisMoment = millis(); // Capture time to measure pre-opening light/sound period CoffinStepNo = sc_StartOpeningLid; // Point to next switch state } break; // Jump to end of switch case sc_StartOpeningLid: if(millis() - MillisMoment >= OpeningLightSoundPeriod) { digitalWrite(OPENclose, HIGH); // Switch linear actuator power route to open lid delay(50); digitalWrite(RUNstop, HIGH); // Apply power to run the linear actuator delay(50); CoffinStepNo = sc_FinishOpeningLid; // Point to next switch state } break; // Jump to end of switch case sc_FinishOpeningLid: if(digitalRead(LidOpen) == HIGH) // If coffin lid limit switch has opened { MillisMoment = millis(); // Capture time to allow time to fully open CoffinStepNo = sc_Extend; // Point to next switch state } break; case sc_Extend: // Jump to end of switch if(millis() - MillisMoment >= ExtraLidMovementTime) // If extra lid movement time has passed { digitalWrite(RUNstop, LOW); // Switch off power to linear actuator delay(50); digitalWrite(OPENclose, LOW); // Power off linear actuator direction relay delay(50); digitalWrite(EXTENDretract, HIGH); // Set pneumatic valve to extend the scissor mechanism CoffinStepNo = sc_HdMp3Busy; // Point to next switch state } break; // Jump to end of switch case sc_HdMp3Busy: if(digitalRead(HdMp3Busy) == LOW) // Wait for head Mp3 player to get active (zombie's talking) { CoffinStepNo = sc_HdMp3NotBusy; // Point to next switch state } break; // Jump to end of switch case sc_HdMp3NotBusy: if(digitalRead(HdMp3Busy) == HIGH) // If zombie has finished talking { MillisMoment = millis(); // Capture time to allow time for zombie to chill CoffinStepNo = sc_StartRetracting; // Point to next switch state } break; // Jump to end of switch case sc_StartRetracting: if(millis() - MillisMoment >= PostTalkingPauseTime) // If it'a timw for the zombie to go back home { digitalWrite(EXTENDretract, LOW); // Set pneumatic valve to retract the scissor mechanism CoffinStepNo = sc_StartClosingLid; // Point to next switch state } break; // Jump to end of switch case sc_StartClosingLid: if(digitalRead(Retracted) == HIGH) // If limit switch indicates scissor mechanism has retracted { digitalWrite(OPENclose, LOW); // Set linear actuator direction relay to close the lid delay(50); digitalWrite(RUNstop, HIGH); // Switch on power to the linear actuator delay(50); CoffinStepNo = sc_LidClosed; // Point to next switch state } break; // Jump to end of switch case sc_LidClosed: if(digitalRead(LidClosed) == HIGH) // If limit switch indicates lid has closed { MillisMoment = millis(); // Capture time to measure post-closure delay CoffinStepNo = sc_LightOff; // Point to next switch state } break; // Jump to end of switch case sc_LightOff: if(millis() - MillisMoment >= PostLidClosurePauseTime) // If desired time has passed since lid closed { digitalWrite(RUNstop, LOW); // Turn off RUNstop relay delay(50); // Debounce 50 ms digitalWrite(WaveLight, LOW); // Turn off Wave Light MillisMoment = millis(); // Capture time to measure post-light delay CoffinStepNo = sc_SoundOff; // Point to next switch state } break; // Jump to end of switch case sc_SoundOff: if(millis() - MillisMoment >= PostLightOffPauseTime) { digitalWrite(Mp3Trigger, HIGH); // Disable Coffin MP3 player CoffinStepNo = sc_AwaitingTrigger; // Loop back to await next trigger } break; // Jump to end of switch } }

[image] bitsoplenty: void loop() { switch (CoffinStepNo) { case sc_AwaitingTrigger: if(digitalRead(Trigger) == HIGH) is Trigger switch closed while inactive? i see nothing what should hang the program. but one thing i would change: just skip time instead of waiting for MP3busy signal. are wires to end switches long?

Too many words - can we have a schematic please? [image] How to make a schematic you can post. Introductory Tutorials When you submit a question on the forum you will usually need to add a schematic (circuit diagram). The tutorial that follows will explain some ways to create a useful image; however lets start by explaining how to add the image to your post. Its easy. Having created the image all you need to do is : Save the image somewhere convenient - maybe your desktop Start your post, and place the cursor (insertion point) where you want the image to be shown; [upload image to forum] 3: click th… Have you debounced the switch inputs (if necessary?) Are your grounds connected properly? [image] skillbank: Experiments and projects with an Arduino microcontroller Ground connections for Arduino and related modules

[image] bitsoplenty: switches a linear actuator (via an electromechanical power and a direction relay) Sounds strange. Normally a pair of SPDT relays are used in an H-bridge circuit. 4 flyback diodes for the motor, in addition to the 2 flyback diodes for the 2 relay coils, are needed. (If using SPDT relay modules, these usually have the flyback diodes for the coils built in, but you still need to add the 4 diodes for the motor, in a diode-bridge configuration.) [image] bitsoplenty: While I continue to suspect a hardware-based problem, Yet you posted your code and not your schematic. Easier for you, I guess.

[image] bitsoplenty: where a pneumatic valve should be activated. What happens if you disable the command for the valve and replace it with a led for example ? (Trying to assess if a current surge cripples your arduino)

[image] bitsoplenty: Any advice about my code or suggestions for diagnosing You could add a default: to your switch statement to catch unexpected values of the switch value. I often do this to catch values which should never happen unless there's a bug. case sc_SoundOff: if(millis() - MillisMoment >= PostLightOffPauseTime) { digitalWrite(Mp3Trigger, HIGH); // Disable Coffin MP3 player CoffinStepNo = sc_AwaitingTrigger; // Loop back to await next trigger } break; // Jump to end of switch default: Serial.println("Invalid switch value = " + String(CoffinStepNo)); } }

Just go to a bit of troubel to avoid using Strings when you do default : Serial.print("Invalid switch value = "); Serial.println(CoffinStepNo); a7

[image] bitsoplenty: Any advice about my code or suggestions for diagnosing and fixing the root cause would be greatly appreciated! I used a stopwatch on my phone to time the linear actuator I used in a similar project. It gave me options like half or quarter open, things like that. It always operates at the exact same speed so it works, if a brutal way of going about it. I also used multiple Arduinos in my similar build. One Mega for the extra hardware UARTs and to direct traffic while waiting for IR readings and RFID scans, also triggers solid state relays for AC lighting, an Uno for the sound (Adafruit Wave Shield), another Uno (or Nano Every - can't remember) for the linear actuator relay board, another Nano Every for the "breathing" light effect.

Is the Trigger switch closed while inactive? i see nothing what should hang the program. but one thing i would change: just skip time instead of waiting for MP3busy signal. are wires to end switches long?aste code here Yes, the trigger switch is closed (pulling the assigned Feather pin to ground) when inactive. Pressing the trigger switch opens it, causing the Feather's internal pull-up to draw it high. I need to wait for the zombie to stop talking before initiating the process of returning him to his coffin and closing the lid. My coffin lid limit switch wires are about 6 feet long. Thanks for your reply!

[image] bitsoplenty: Any advice about my code or suggestions for diagnosing and fixing the root cause would be greatly appreciated! The flow seems ok, using Serial chars to navigate around I was able to get through your sketch. Check out what I changed and/or disabled (commented out) to see if it gives you a eureka moment. #define OpeningLightSoundPeriod 5000 // Pre-opening sound period in ms #define ExtraLidMovementTime 3000 // Extra time (ms) to make sure lid fully opens/closes #define PostTalkingPauseTime 4000 // Time (ms) for zombie to chill after saying his piece #define PostLidClosurePauseTime 2000 // Time (ms) from lid closure to light & sound off #define PostLightOffPauseTime 5000 // Time (ms) from light off to sound off after lid closure #define RUNstop 0 #define OPENclose 1 #define WaveLight 5 #define EXTENDretract 6 #define LidOpen 9 #define LidClosed 10 #define Trigger 11 #define Extended 12 #define Retracted 17 // Formerly 13 #define Mp3Trigger 14 // FN-BC10 Level Hold Loop Playback (Mode 1). Hold trigger pin low for playback duration #define HdMp3Busy 15 #define CofMp3Busy 16 const byte sc_AwaitingTrigger = 1; // If triggered, turn on WaveLight & lower CofMp3 trigger (sound begins) const byte sc_StartOpeningLid = 2; // Wait 5 sec before opening coffin lid const byte sc_FinishOpeningLid = 3; // If OPEN limit switch = HIGH, start 3 sec extra movement timer const byte sc_Extend = 4; // Disable lid actuator. Turn on PValve (zombie begins to rise) const byte sc_HdMp3Busy = 5; // Wait until HdMp3 is LOW (busy, zombie starts talking) const byte sc_HdMp3NotBusy = 6; // Wait until HdMp3 is HIGH (not busy, zombie stops talking) const byte sc_StartRetracting = 7; // Wait 4 sec then turn off PValve (begin to retract) const byte sc_StartClosingLid = 8; // If RETRACTED limit switch is HIGH, start closing lid const byte sc_LidClosed = 9; // If CLOSED limit switch is HIGH, start 2 sec post closure timer const byte sc_LightOff = 10; // Turn off WaveLight then start 5 sec post light timer const byte sc_SoundOff = 11; // Raise CofMp3 trigger (coffin sound off). Loop back to await next trigger byte CoffinStepNo = sc_AwaitingTrigger; bool thisTrigger = 0; bool lidOpened = 0; unsigned long MillisMoment; void setup() { Serial.begin(115200); pinMode(RUNstop, OUTPUT); pinMode(OPENclose, OUTPUT); pinMode(WaveLight, OUTPUT); pinMode(EXTENDretract, OUTPUT); pinMode(LidOpen, INPUT_PULLUP); pinMode(LidClosed, INPUT_PULLUP); pinMode(Trigger, INPUT_PULLUP); pinMode(Extended, INPUT_PULLUP); pinMode(Retracted, INPUT_PULLUP); pinMode(Mp3Trigger, OUTPUT); pinMode(HdMp3Busy, INPUT); // Active low pinMode(CofMp3Busy, INPUT); // Active low digitalWrite(RUNstop, LOW); // Initialize output levels digitalWrite(OPENclose, LOW); digitalWrite(WaveLight, LOW); digitalWrite(EXTENDretract, LOW); digitalWrite(Mp3Trigger, HIGH); Serial.println("\nCurrent CoffinStepNo: sc_AwaitingTrigger"); Serial.println("sc_AwaitingTrigger, type in 1 to trigger\n"); } void loop() { if (Serial.available() > 0) { char inChar = Serial.read(); switch (inChar) { case 'a': CoffinStepNo += 1; break; case 'd': CoffinStepNo -= 1; break; case '1': thisTrigger = 1; break; case '0': thisTrigger = 0; break; case 'w': lidOpened = 1; break; case 's': lidOpened = 0; break; } } switch (CoffinStepNo) { case sc_AwaitingTrigger: // 1 if (thisTrigger == 1) { printState(CoffinStepNo); digitalWrite(WaveLight, HIGH); // Turn on Wave Light digitalWrite(Mp3Trigger, LOW); // Initiate falling edge of MP3 board trigger MillisMoment = millis(); // Capture time to measure pre-opening light/sound period CoffinStepNo = sc_StartOpeningLid; // Point to next switch state } break; // Jump to end of switch case sc_StartOpeningLid: // 2 if (millis() - MillisMoment >= OpeningLightSoundPeriod) { printState(CoffinStepNo); digitalWrite(OPENclose, HIGH); // Switch linear actuator power route to open lid delay(50); digitalWrite(RUNstop, HIGH); // Apply power to run the linear actuator delay(50); CoffinStepNo = sc_FinishOpeningLid; // Point to next switch state } break; // Jump to end of switch case sc_FinishOpeningLid: // 3 if (lidOpened == 1) // If coffin lid limit switch has opened { printState(CoffinStepNo); MillisMoment = millis(); // Capture time to allow time to fully open CoffinStepNo = sc_Extend; // Point to next switch state } break; case sc_Extend: // 4 if (millis() - MillisMoment >= ExtraLidMovementTime) // If extra lid movement time has passed { printState(CoffinStepNo); digitalWrite(RUNstop, LOW); // Switch off power to linear actuator delay(50); digitalWrite(OPENclose, LOW); // Power off linear actuator direction relay delay(50); digitalWrite(EXTENDretract, HIGH); // Set pneumatic valve to extend the scissor mechanism CoffinStepNo = sc_HdMp3Busy; // Point to next switch state } break; // Jump to end of switch case sc_HdMp3Busy: // 5 // if(digitalRead(HdMp3Busy) == LOW) // Wait for head Mp3 player to get active (zombie's talking) // { printState(CoffinStepNo); CoffinStepNo = sc_HdMp3NotBusy; // Point to next switch state // } break; // Jump to end of switch case sc_HdMp3NotBusy: // 6 // if(digitalRead(HdMp3Busy) == HIGH) // If zombie has finished talking // { printState(CoffinStepNo); MillisMoment = millis(); // Capture time to allow time for zombie to chill CoffinStepNo = sc_StartRetracting; // Point to next switch state // } break; // Jump to end of switch case sc_StartRetracting: // 7 if (millis() - MillisMoment >= PostTalkingPauseTime) // If it'a timw for the zombie to go back home { printState(CoffinStepNo); digitalWrite(EXTENDretract, LOW); // Set pneumatic valve to retract the scissor mechanism CoffinStepNo = sc_StartClosingLid; // Point to next switch state } break; // Jump to end of switch case sc_StartClosingLid: // 8 // if(digitalRead(Retracted) == HIGH) // If limit switch indicates scissor mechanism has retracted // { printState(CoffinStepNo); digitalWrite(OPENclose, LOW); // Set linear actuator direction relay to close the lid delay(50); digitalWrite(RUNstop, HIGH); // Switch on power to the linear actuator delay(50); CoffinStepNo = sc_LidClosed; // Point to next switch state // } break; // Jump to end of switch case sc_LidClosed: // 9 if (lidOpened == 0) // If limit switch indicates lid has closed { printState(CoffinStepNo); MillisMoment = millis(); // Capture time to measure post-closure delay CoffinStepNo = sc_LightOff; // Point to next switch state } break; // Jump to end of switch case sc_LightOff: // 10 if (millis() - MillisMoment >= PostLidClosurePauseTime) // If desired time has passed since lid closed { printState(CoffinStepNo); digitalWrite(RUNstop, LOW); // Turn off RUNstop relay delay(50); // Debounce 50 ms digitalWrite(WaveLight, LOW); // Turn off Wave Light MillisMoment = millis(); // Capture time to measure post-light delay CoffinStepNo = sc_SoundOff; // Point to next switch state } break; // Jump to end of switch case sc_SoundOff: // 11 if (millis() - MillisMoment >= PostLightOffPauseTime) { printState(CoffinStepNo); digitalWrite(Mp3Trigger, HIGH); // Disable Coffin MP3 player Serial.println("sc_SoundOff"); CoffinStepNo = sc_AwaitingTrigger; // Loop back to await next trigger Serial.println("\nCurrent CoffinStepNo: sc_AwaitingTrigger"); Serial.println("sc_AwaitingTrigger, type in 1 to trigger\n"); } break; // Jump to end of switch } } void printState(byte CoffinStepNo) { byte thisStepNo = CoffinStepNo; Serial.print("\nCurrent CoffinStepNo: "); switch (thisStepNo) { case 1: Serial.println("sc_AwaitingTrigger"); break; case 2: Serial.println("sc_StartOpeningLid"); Serial.println("type w to simulate coffin lid limit switch has opened"); break; case 3: Serial.println("sc_FinishOpeningLid"); break; case 4: Serial.println("sc_Extend"); break; case 5: Serial.println("sc_HdMp3Busy"); break; case 6: Serial.println("sc_HdMp3NotBusy"); break; case 7: Serial.println("sc_StartRetracting"); break; case 8: Serial.println("sc_StartClosingLid"); Serial.println("type s to simulate coffin lid limit switch has closed"); break; case 9: Serial.println("sc_LidClosed"); break; case 10: Serial.println("sc_LightOff"); break; case 11: thisTrigger = 0; break; } Serial.println(); delay(500); }

[image] PaulRB: Normally a pair of SPDT relays are used in an H-bridge circuit. I'm using one relay to gate power to a second DPDT relay which selects which linear actuator motor terminal is at +12V vs. ground.

Intermittent skip of Switch case (jumping to limbo?)

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johnerrington October 11, 2024, 5:48am 3

Too many words - can we have a schematic please?

Have you debounced the switch inputs (if necessary?)

Are your grounds connected properly?

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Intermittent skip of Switch case (jumping to limbo?)

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