Rotary phone ringer

Using Arduino Project Guidance
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Hi, y'all, I'm working on a project which is essentially converting a rotary phone into a smart home device. I've got the dialer and hook circuits up and working with my Uno Wifi Rev 2, but I'm running into some real issues with the ringer. I've been referring to this tutorial and this one for the most part, but they're kinda sparse as far as fine details on how they got their ringers to work. I've created an electromagnet using magnet wire, and I can ring the bell by just connecting the the electromagnet to an 9v battery.

I've tried using an l298n driver to turn the magnet on and off, which is what the person in the first tutorial did, but this doesn't seem to do anything (code below). I've also tried (very naively) to use a relay module I had lying around to simply turn power on and off to the magnet, but that doesn't do anything either, it's very likely relays don't work the way I think they do. I'm using a Keyestudio brand module that I got with a sensor kit, and I've got the +9v of the battery plugged into the middle port and the magnet plugged into the right port. The other wire of the magnet and the battery's GND are plugged into GND on my breadboard.

A couple pieces of information that may be helpful, I've seen other phones which have two electromagnets which pull the mallet back and forth. My phone had one electromagnet (which required too much power, so I made a homemade one) and one regular magnet. The regular one keeps the mallet in place until the electromagnet is turned on, at which point it will smack one bell. Then when the magnet is turned off, the mallet returns to its original position and smacks the other bell. At least this is how I think it works. I don't think I need to reverse polarity on the magnet, but I could be wrong. Also, I've connected my 9v battery and the magnet to a breadboard, expecting the mallet to stand attention, but I had to mess with the magnet's wires a bit to get it to turn on. Maybe the 28 AWG magnet wire is too thin for my driver and relay, and it's not making a good connection? Finally, it's only allowing me to have two links in this post, so I'll comment with some more links.

I'm a complete novice, so I'm at my wit's end at this point. Can y'all think of anything I could try? Thanks in advance.

#include "Arduino.h"

void setup(void) {
  Serial.begin(9600);
  Serial.println("START");
  pinMode(6, OUTPUT); // Input 1
  pinMode(7, OUTPUT); // Input 2
}

void loop(void) {
  digitalWrite(6, LOW);
  digitalWrite(7, HIGH);
  Serial.println("ON");
  delay(1000);
  digitalWrite(6, LOW);
  digitalWrite(7, LOW);
  Serial.println("OFF");
  delay(1000);
}
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We really need to see a schematic of what you are trying to do.

An Arduino output pin should not be connected to a load of more than 20mA, and should never be exposed to a voltage greater than 5V. Otherwise the Arduino pin can burn out, sometimes even the whole Arduino.

An L298 is not very suitable for switching 9V because you loose to much voltage across the transistors, you need a higher voltage on the motor supply or a better driver.

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You my find something you can use here. I’ve published a few telephone projects in the exhibition gallery in this forum.

Both designs use an L293 motor driver and a step up boost converter.

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Thanks for the replies. @Grumpy_Mike I went ahead and ordered a BD65496MUV after Googling for "good DC motor driver." (that should be a good indication of much of a novice I am) Do you think this would be adequate or do you have a better suggestion? On the schematic, I messed with a couple free schematic tools online, and they're pretty overwhelming. Can you suggest a free tool that's more n00b friendly?

@6v6gt Thanks! These are great! They might be a little advanced for me, but I'll give it a shot. I'm kind of confused about the boost converter in the schematic in the first link you shared. Is that a chip or a breakout board or some kind of circuit? I may be missing it, but I don't see any kind of label on it.

5

To avoid duplication it would help to know the ones you've looked at.

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Yes they are. I don’t use them these days. What I do is just use a normal 2D drawing program called MacDraft. That way you can build up your own bank of symbols and arrange things how you want. Most cheap schematics software is so limited and as you say overwhelming.

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It is a boost converter module type xl6009 found on eBay. For example: XL6009 DC Adjustable Step up boost Power Converter Module Replace LM2577 | eBay

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I tried scheme-it and smartdraw. I guess all I really need to do for the simple circuits I'm trying to describe is draw some rectangles, lines, and text. There are no capacitors or resistors or anything. I'll just jump on Gimp after work and doodle it up.

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Well Gimp is a raster based system working on pixels, you will be better off using a vector graphic package like Inkscape. They are much easier to move stuff around and they are scale independent meaing you can make them as big as you like without loosing any resolution.

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Pencil and paper can also work very well for drawing schematics and there is a fine example at the end of the following link. You’ll also see why Fritzing diagrams are not really regarded here as a good substitute for a schematic. If you get as far as ordering printed circuit boards you’ll then have to start using a schematic editor.

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