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Zener Diode heat

Issues
2022-03-06
2023-12-07
  • Damon Ferguson

    Damon Ferguson - 2022-03-06

    Hello
    I was wondering if it is normal for the zener diode withing your circuit is suppose to generate heat to the point where you can't touch it without buring yourself? I don't really recall it doing that on the initial build and I didn't realize it until much later when I decided to rebuild the build and I removed it from its temporay case and upon hadling it, I hard to jerk my hand away as it was so hot. I do have another question regarding the coding: Is there a way or how do you code it so the servo moves slower? I am asking because I have an 8 in Newt I want to adapt this project to. I have tested it on that scope and everything seems fine except, because of the weight of the cover, the sudden stops causes the cover to jerk (bounce), if that makes since. I figured I could eliminate that by making the motor open the cover slower. I just don't know how to modify the code to make this happen.
    The original build with my WOZ81 does work, I am just concerned about the amount of heat being disapated.

    Thanks for you time.

    P.s.
    When everything looks pretty, I will post pics on CN

     
  • Nathan Woelfle

    Nathan Woelfle - 2022-03-07

    Hi Damon,

    Thank you for reaching out with your questions. The Zener diode may be a little warm, but it should not be hot to the touch; it sounds like there may be a problem. Regarding slowing the servo speed, this can be accomplished. You will need to download the VarSpeedServo library, replace #include <servo.h> with #include <varspeedservo.h> and Servo myservo; with VarSpeedServo myservo;. Afterward, you'll have to find the best value by updating the servoSpeed variable. I hope that helps; if you need anything else, let me know. I'll have to check in on CN; I haven't been on there in a long time.</varspeedservo.h></servo.h>

    R/
    Nathan

     
  • Damon Ferguson

    Damon Ferguson - 2022-03-07

    Thanks for getting back with me. I setup a bench test for the 1N5346B zener with a 15 ohm res, a 10A10 rectifier diode and a 12vdc power supply. Voltage out was 9.4 something volts. It still gets very hot. I measured (not very accurately) (with a food thermometer) a temp of about 145 degrees F. I have it plugged in still and waiting to see if it melts. I will try the varspeedservo once I can figure out the zener. Oh and by the way, I would be very intrested in when you get around to using a stepper motor instead of a servo. I like steppers more thean servos.

    Damon

     
  • Nathan Woelfle

    Nathan Woelfle - 2022-03-09

    Oh and by the way, I would be very intrested in when you get around to using a stepper motor instead of a servo. I like steppers more thean servos.

    One day. It's something on my to-do list.

     

    Last edit: Nathan Woelfle 2022-03-09
  • Damon Ferguson

    Damon Ferguson - 2022-03-10

    OK, so i have resolved the hot zener diode issue. I swapped out the 15 ohm resistor for a 51 ohm. Voltage is sitting around 9.2v and the zener is just warm. Everything seems to work and I am satisifed.

     
  • Nathan Woelfle

    Nathan Woelfle - 2022-03-14

    Excellent, I'm glad it was an easy fix for you. Good luck with the rest of your build. If you have any troubles with the variable speed, please let me know.

    R/
    Nathan

     
  • Mauricio Veronesi

    Hello Nathan
    Could you explain me in detail how to include the speed variable in your code?
    I already downloaded the VarSpeedServo.h library and replace #include <servo.h> with #include <varspeedservo.h> and Servo myservo; with VarSpeedServo myservo;
    Thank you</varspeedservo.h></servo.h>

     
  • Nathan Woelfle

    Nathan Woelfle - 2022-05-23

    Hi Mauricio,

    I apologize, there are a few more changes that are required. I have sent you a PM. Let me know and hopefully we can get you up and running.

    Thanks,
    Nathan

     

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