Good Morning from my Robotics Lab! This is Shadow_8472, and today I am building a model telegraph. Let’s get started!
The First Telecommunications
The electric telegraph was invented not long after the discovery that electricity and magnetism were two faces of the same fundamental force of nature. While the image of someone tapping out a message in Morse Code may involve the more iconic piece of hardware –the key– the real heart of the technology is located in the sounder: an electromagnet controlled from miles away. This was what powered the first ever near-instantaneous telecommunications networks crossing America and later the world.
Only limited by the speed of an operator and final delivery, a message from the front lines of the American Civil War could reach Abraham Lincoln in hours or minutes instead of potentially days. It put the Pony Express out of business almost before it got started. It remained unchallenged until Alexander Graham Bell invented the telephone by sending enough information over the wire to reconstruct a human voice – and in fact, smartphones and other personal computing devices still contain the humble electromagnet to deliver convert electrically encoded messages into sounds we can understand.
3D Printed Telegraph Key and Sounder
This project was sparked a post by Mattosx on instructables.com[1]. I’ve already spoken about the issues I had printing this project. Between all the totally failed prints, a case of broken filament, and the slightly peeled pieces, I am lucky to have two sets of parts, though some may need reprinting.
Researching a Group
I have always been at least passively curious about learning Morse. I started seriously looking into it this month. Who all still uses dots and dashes to communicate? Ham radio operators, mostly. I neither have the equipment nor the desire to get the license I would need before participating in clubs using Morse over CW (communications waves).
While musing that I might connect my telegraph over the Internet, I came across Morse KOB on GitHub, apparently the only software tool out there for such a purpose. I reached out to Ed Silky, the only developer I could find contact information for. I figured I might as well so I eventually have a point of contact by the time I finish the Instructable. He responded by the next morning.
Ed shared a wealth of information I had only started piecing together. He called my attention to a critique in the Instructable’s comments, that the sounder doesn’t signal the end of a dot/dash clearly as or distinctly from the beginning of one. Ed warned, “Also, be aware of the differences in the alphabet between American (Landline/sounder) and International (Shortwave/tone / Light) code:” and listed eleven characters and all ten digits with their differing encodings; the earlier American Morse features such things as intra-character spaces and extended dashes – making a properly functioning sounder crucial to understanding American Morse in particular [2].
Assembling the Key and Sounder
Mattosx’s Instructable looks great… until you’re actually part way into assembling the thing. The first red flag is a privated video titled “3D Printed Telegraph Sounder Video” with no written instructions outside the parts list.
The Instructable I’m following is crippled, but I’m limping through it. The 3D modeling isn’t the cleanest on a couple parts – and in fact is missing a piece on closer inspection. I had to creatively chop the parts apart in Slic3r to get them to fit on my damaged bed. Without that video on the sounder assembly, we had to guess at the size of magnet wire, what direction the disks were pointing (in or out), even what order to assemble the different parts in. It’s an interesting idea to make the sounder handle its own electromagnet, but that optional part is unapproachable without any experience working with circuits.
My father and I wound the electromagnet over several sessions, with the internals getting progressively less tidy as mistakes compounded upon each other. By the end, I was just trying to fill in low spots. We hooked it up to two D cell batteries by hand and nothing. We tried a multimeter, but that turned up busted, so I’m left with a project to continue some time in the future.
Takeaway
Based on my incomplete attempt to build this thing, here are my recommended modifications (note that I have not actually tried these yet):
- Install magnets, using sandpaper to make the holes a little bigger if need be.
- Screw in and wire up the key base before installing the key.
- For the sounder electromagnet, search out some sort of spool winding tool to print.
- Start with the nubs facing outward instead of inward.
- Dry fit the spool so the upper plate lines up with the tops of the base’s posts.
- Use a power screwdriver to grab the screw right where the upper plate would otherwise land.
- Once you have the electromagnet wound, assemble the top of the sounder.
- If all the screws are so loose they fall out, use a snip or few of magnet wire to crowd the screw hole (untested, but this might be a good use for any lines of filament extruded as part of bed leveling prints).
This was my first larger monthly project. It didn’t meet my personal deadline of having a working model to post today because I failed to plan. I only had magnets in hand with a week to go, and I didn’t leave myself any time to diagnose problems as they came up. I now have another project to cycle through as time allows.
Final Question
Have you ever made an electromagnet by hand before? I look forward to hearing your answer in either the comments below or on my Discord server.
Works Cited
[1] Mattosx, “3D Printed Telegraph Key & Sounder,” instructables.com, (no later than March 12, 2019 [3]). [Online]. Available: https://www.instructables.com/3D-Printed-Telegraph-Key-Sounder/ [Accessed April 25, 2022].
[2] E. Silky. “Re: MorseKOB,” “Re: Telegraph Build,” Personal emails (April 7, 2022 to April 22, 2022).
[3] T. Nardi, “Old Meets New In 3D Printed Telegraph,” hackaday.com, March 12, 2022. [Online]. Avalable: https://ieee-dataport.org/sites/default/files/analysis/27/IEEE%20Citation%20Guidelines.pdf [Accessed April 25, 2022].