The arrival of me with my belongings; MacBook pro with local LLM and prepper library focused on community rebuilding and whole Wikipedia and WikiHow library. My phone which is pretty much useless other than taking photos or recording videos. Solar charger portable that takes 2 full sunny days to fully charged my MacBook pro. Few pair of clothes that isn’t looking medieval, like jeans, shirt, one shoes. And my Motorcycle; Honda CB Verza 150cc, gasoline powered.
I arrived via a portal from my home to just outside the perimeter of Alhambra. The same portal only be opened again in The "Melanchthon" Total Solar Eclipse of April 17, 1540
I came to the palace, fluent in Arabic, said Salaam and claiming to be refugee from far east of China. The guards escorted me to the court to meet with the Emir. I said that a humble, Muslim trader man from Spain saved me from Mongol raids on my land. I lost my family there and traveled to Iberia to seek refuge, and I offered the Emir what my family has invented, instantaneous communication between his holding or provinces, electricity, and powerful firearms to fight back against the Castile.
Emir raised his eyebrows, and said, if I had such technology why would I lost to simple Mongol raid? I said to him that My family and I had no manpower to overcome their forces, despite killing hundreds of them. And the self destruct sequence saved me and my family legacy to ever fell to the wrong hands.
The Emir and the whole court room was in silence, shutting off the skeptics, as I show them the recording on my phone how the raid was happened (it’s a movie clips, edited). The Emir approached me and hugged me, gave his condolences and asked if I am a Muslim, and I said yes.
He asked to gather every scientists of Granada in Alhambra as he arranged a meeting of them and me tomorrow. As I was given a room and accommodation to settle.
The moment arrived, at least 25 scientist in an empty large room, we are all sitting down on the mattress/pillows on the floor. I showed them what knowledge I posses, and I’d need hundreds of scribes to built a library of the knowledge I have on my MacBook.
Some of the scientists are specialized in metallurgy while half of them are Mathematicians and Alchemists.
After the meeting, the Emir and I created the order; House of Wisdom, first day is to explain what electricity is and how to built them, what they are used for, and more. Planning and sketching the power plant, windmills at the hills, wheel generator in river streams. All while I left the MacBook on so the scribe able to copy the knowledge (most PDF are only 10-100 pages long) that already translated to Arabic by the local LLM.
The next day is material gathering, while the other build the windmill and the wheel, two prototypes are planned. Sourcing the components first; Lodestone, Copper and more, the small prototype from Lodestone is used for magnetizing iron and eventually a permanent steel magnets. Once we generated even a tiny bit of electricity with the first weak generator, we can use that current to power an electromagnet, which can then permanently magnetize much stronger steel bars. Now the wires are made from copper, we will need a metalsmith to draw copper through progressively smaller holes in a steel die plate until you get long, thin, flexible wire. The insulation will be made of natural lacquer, shellac, or pine resin mixed with beeswax, or by meticulously wrapping the wire in thin strands of silk or linen thread.
Designing the generator (Alternator) or Axial Flux Alternator. The Magnet Discs (The Rotor); is created from wooden or iron disc that fixed directly to the rotating shaft of the windmill or waterwheel. Magnets are mounted around the edge of the discs, alternating North and South poles (N-S-N-S). The Coil Ring (The Stator) is a stationary wooden frame right next to the spinning disc. On this frame, mount the hand-wound copper coils. The coils should be shaped like loops (or donuts) and positioned so that the spinning magnets pass directly over the holes of the coils, as close as possible without touching. As the waterwheel turns the shaft, the magnets sweep past the copper coils. The changing magnetic field forces the electrons in the copper wire to move, generating an electric current.
The basic generator described above will produce AC, the electricity constantly changes direction as North and South poles alternate past the coils. We will need DC. We can build a Mechanical Commutator or mechanical switch on the rotating shaft. This involves splitting a copper sleeve on the shaft into segments separated by wood or air. Stationary copper strips ("brushes") rub against this spinning sleeve. If aligned correctly, the brushes switch contacts right as the current changes direction, flipping the AC into bumpy DC.
The tuning is needed for both waterwheels and the windmills. For waterwheels (high torque, low speed), it turns slowly but with massive force. Because it moves slowly, a generator won't produce much voltage unless used a gearing (wooden peg-and-lantern gears) to step up the rotational speed, or wind a massive number of turns into your copper coils. For windmills (lower torque, variable speed), it spin faster but can stall if the electrical load is too heavy. We will need a way to adjust the sails or blades to handle the mechanical resistance that occurs the moment we connect our generator to a heavy electrical load.
This projects going on for months while another team is working on a telegraph to test if the electricity works while also developing our own Morse code. The receiver is made from A soft iron bolt or large nail as the core, Wrap hundreds of turns of the insulated copper wire tightly around the iron bolt. This is will be the electromagnet, the coil. A small brass or iron peg for the lever to hit when it snaps down, making a loud, distinct click as the striker. The sender or the key is the easiest part; A wooden lever pinned at a pivot point. Two copper or brass contacts. One contact is fixed to the table; the other is attached to the bottom of the wooden lever right above it. A small spring keeping the contacts separated. When its pushed down on the key, the contacts touch and complete the circuit. When its let go, it springs back up and breaks the circuit.
Drawing miles of copper wire is incredibly resource-intensive. Because telegraphs don't require massive amounts of current, we can actually switch to iron wire for the long distances between cities. Iron has higher resistance than copper, but it is vastly cheaper to produce in medieval blast furnaces, stronger over long spans, and less likely to be stolen by locals who know the value of copper. The insulator is crucial, we can’t just nail bare iron wire to wooden poles or castle walls; the electricity will leak straight down the wet wood into the ground. Ceramic or glass insulators are needed. We can have a local potter bake small, unglazed porcelain or glazed stoneware cups with a groove wrapped around the middle. Then mount these ceramic cups to the wooden poles, and tie the telegraph line around the ceramic. Glass or glazed ceramic won't conduct electricity, keeping the signal trapped in the wire.
We’d also need to developed a battery, the kind we used to power telegraphs back in the day. it is a modification of the Daniel Cell called the Gravity Cell (or Crowfoot Cell). The materials we need; 1) glass jars or ceramic crocks, we need deep containers. Transparent glass is highly preferred here because we need to visually check the battery's health. 2) Copper (the positive terminal), hammered copper sheets shaped like a cross or a star that sit flat at the very bottom of the jar. 3) Zinc (the negative terminal):, a heavy piece of cast zinc shaped like a crow's foot (hence the historical name) that hangs from the top rim of the jar. 4) Copper sulfate crystals (CuSO4 / blue vitriol) is dumped right onto the bottom copper plate in plentiful quantities. 5) Water and a pinch of zinc sulfate (or just plain saltwater) to fill the rest of the jar. For the assembly, let gravity do the work. Instead of a physical barrier, this battery uses the differing densities (specific gravity) of the two chemical solutions to keep them separate. The bottom layer; place the copper star at the bottom of the glass jar. Connect an insulated copper wire to it and run it up out of the top of the jar. Dump a thick layer of blue copper sulfate crystals right on top of the copper. Carefully pour clean water into the jar, filling it near the top. Try not to agitate the crystals too much. The top layer is the zinc "crow's foot" being hanged from the top rim so it is submerged in the upper portion of the water. As the copper sulfate crystals dissolve, they create a heavy, dense, blue solution that stays pooled at the absolute bottom of the jar. Over time (or instantly if we add a little zinc sulfate/salt to the top), a lighter, clear zinc sulfate solution forms at the top around the zinc. As long as the battery stays perfectly still on a shelf, the blue solution and the clear solution will stay separated like oil and water, meeting at a distinct visual line right in the middle.
Why the battery is perfect in this scenario? It has zero self-discharge, unlike the original Daniel cell, if a Gravity Cell is kept connected to a continuous, light electrical load (which a telegraph system provides), the chemical boundary line stays perfectly stable. It can sit on a shelf operating for years with zero maintenance. Because we are using glass jars it can act as visual gauging, we (or the operators) can literally see when the battery is dying. If the blue line at the bottom starts dropping too low, it means we need to drop more blue vitriol crystals into the jar. If the top gets cloudy, we draw off some of the top liquid and replace it with fresh water.
To send a signal down an iron wire spanning 20, 50, or 100 miles, we need to chain these cells together in Series (Positive terminal of cell 1 to Negative terminal of cell 2) to build up high voltage.
Late 1481, we have two working fully built generator, the Telegraph network is first built from Alhambra to Almeria. In a modern circuit, we’d need two wires: one going out, and one coming back to complete the loop. Running two lines across a medieval kingdom doubles the cost. Instead, we can use the Earth Return trick discovered in the 1830s. In Alhambra, connect the battery to the key and then the key to the long distance line. Run that single line to Almeria on poles. In Almeria connect the line to the receiver/the sounder. The trick is to take the remaining wire from the Almeria and solder it to a massive sheet of copper and bury it deep in the wet ground. Back in Alhambra, take the negative terminal of the battery and bury the similar copper plate deep in the ground there. So the whole setup is; The Central Station is build sturdy, vibration-free wooden rack in the castle's telegraph room. The battery bank is lined up roughly 20 to 50 Gravity Cells on the rack connected in series. This will output roughly 22 to 55 volts. This is more than enough punch to overcome the electrical resistance of miles of hand-drawn iron wire and successfully snap the iron armature of your receiver on the other side of the kingdom.