We are building hygrometers, and manometers to become thermometers, and what I call combo LED lamps but my mind wanders and I think about building more automated systems, and alarm systems. There is already a battery bank and electricity here, and a electric bell is easy. Above all, an alarm can be practical for doors that no one should normally use, for example if someone opens the hidden door to the basement vault or the iron bar door inside the basement vault, a bell can start ringing in the guards day room. An alarm button in the day room can also ring a bell in the guards bedroom.

It can also be a good idea to build a system for summoning the maids. Although I would prefer to have a simple telephone system for it in the future, it is a good idea with something until then. Caecilia is usually nearby, even if her personal assistant role has really become more of a courtesan that do some maid and assistant duties too, which I should have expected. Not unexpected is that I don't like to have her sitting next to me just waiting to be off service, even though she seems to want to spend much more time near me, and be 'available'. Basically Caecilia cleans my rooms, takes care of my clothes and shoes, and is sent on short errands and sometimes we are intimate, with or without Iselin. If I want a glass of water, I usually get it myself. But I don't like seeing usually Elvira sitting there just waiting on a chair on the balcony, ready to be of service, and having to shout etc. Some kind of system would be good, and the electrical wires are already drawn.

So we work and make small jokes and talk. Iselin and Kari help me build gauges while Ciara is make another math book. I let Iselin be in charge of most of the gauge work, while I instead winds coils and make simpler relays with double switching contacts.

An electric bell is an electromagnet, which attracts a percussion arm that strikes a bell when the electromagnets coil is energized, where the percussion arm otherwise springs away and rests against a small contact plate. But the current to the electromagnet goes via the percussion arm and this contact plate, so when the electromagnet pulls the percussion arm towards itself, the current is interrupted and the arm springs back after the percussion arm has hit the bell. This causes the electromagnet to receive current again and repeat another stroke on the bell etc. RIIIIINNGG.

An electromagnet that affects an arm with electrical contacts is the basis of electromechanics. Basically the same thing electrically changes what it is depending on what that arm does or what the purpose is. A relay. An oscillator. A buzzer. A bell. An arm that steps forward a counter is an electric pulse counter. An arm that makes marks on paper or the like is a form of printer. It's electromechanics. It is relatively recent that semiconductors competed and took over from electromechanical switching systems in telephone exchanges. The oldest telephone systems used plugboards where an operator physically connected lines together, but it was replaced with an ingenious system that combined a phone with a dial that made electrical pulses when dialling a number. Those pulses made a contactor arm gradually rotate to the side, step by step. Later systems became more complex and moved in height and to the side. Two electromagnets that chose one of 100 lines very fast. Nowadays, there are tone coding and electronic switches, but there are probably some electromechanical telephone systems left somewhere in Midgård. With enough relays of the right contact type and correctly connected, it is even possible to build a relay computer. A very power consuming, slow and loudly clicking computer, but it works. If there are locking relays where only the actual switching pulse draws current, then it can be relatively energy efficient. Very capable computers have been built with thousands of relays, although they won't play Doom. Their output is generally on an electromechanical printer. Historically speaking, most hard working scientific and business computors output on paper, not on screens.

I want a 'service system', and I have come up with a way to signal which room made 'the call' with a simple electromechanical circuit. In each room with a call button there will be a small box with a button to press for service, and under a safety hatch an alarm button to call guards. The system requires two signal wires per room. The service signal goes to the servants 'staff room' while the similar alarm system goes to the guards day room.

When you press the button, it almost works like a bell. An electromagnet is activated and via a small arm a cylinder is stepped forward 1/16 step of a full revolution, but this stepping temporarily breaks the force of the electromagnet, so the arm springs back, connects the current to the electromagnet, which steps forward another step and so on. The cylinder gradually rotates at a high pace. But at the end of the cylinder is an arm that affects a special plate full of contacts, and breaks a contact in each step. There are many push buttons, up to 16, which all have their own line to the cylinder stepping system via these end contacts. So when the cylinder has broken the contact that gives current to the electromagnet, the rotation stops. Along the side of the cylinder can then be a text that describes which room the button is in.

It is a simple construction, and should be reliable if I get the contact working well. There are some drawbacks to the system, like every room needs separate wires, which I however have laid enough of, and the amount of steps on a cylinder. Yes, it can have more or less than 16 sides, but there are good reasons not too. One issue is voltage drops in wires, but it can be solved with an intermediary relay that drives the stepping directly in the receiver unit. Other issues are that it won't work to call from the same button twice in a row, because its line is disconnected, and that the push button must be held down long enough for the cylinder to rotate and break connection. Another problem is if someone else calls before the maids have time to check, because they then miss the previous one. But it's all manageable, and just something we have to live with.

To attract the staffs attention, the receiver unit will have a small buzzer or bell that is active while it is rotating. In order to not show all the text of the cylinder as it rotates a whole revolution as some places are 'secret', there will be a small electromagnet that with a small privacy shield hides the text until the voltage is lost and everything stops. The stepping, bell and privacy shield will draw a lot of current, so to reduce the impact of long wires, there will be an intermediary relay to drive them. To make it possible to use the same button twice in a row, a step is sacrificed as a blank reset, and there is a button on the device that the staff can push to reset when they have read the room text, but that button won't activate the bell.

I was thinking of a more complex pulse system, where each button generates its own pulse code, and everyone uses the same line to the receiver and so on. But it requires a lot more mechanics in each push button, and basically a variant of an old mechanical pulse phone. It may be in the future, but not now. Should I try to build a pulse dial call system, I might as well try to build a real telephone with voice.

This tale has been unlawfully lifted from Royal Road. If you spot it on Amazon, please report it.

The alarms to the guards are the same system, but it is divided over the most important rooms and zones. A zone is, for example, the east side of the main building's second floor, and so on. This system can also be connected to vault alarms etc, and I would really like a light signal so it can be quieter, so maybe put a strong LED and a weaker muted buzzer sound at night. One of the reasons for zones is that there are not enough wires, and the guards simply have to check around the zone why there was an alarm.

It sounds quite complex but is really just mostly simple push buttons, as well as a hell of a lot of copper wires, a bunch of electromagnets, brass and wood.

I will build a test system and make sure it works before I present the idea to everyone, but Iselin, Kari, Ciara and Alith likes it. Alith wants there to be an alarm bell in their bedroom as well. If an alarm is triggered, it is bad so everyone needs to react, whether they are in the bedroom or the day room, and it is better that guards come from several directions. The bells probably won't be that loud, but they can be really loud if the bell is big enough and the electromagnet strikes hard enough. Electromechanical fire alarm bells sound quite well. Springs are a problem, because I have none in steel and brass is less good than spring steel, but I have to try it out to make something that works. We can always change for the better in the future. The whole idea with the junction boxes and the wires I have drawn is for the wires to be there. It is not difficult to change what the wires are used for.

So I continue on the combo LED lamps, while Kari keeps working on gauges while Iselin jumps between that and helping Ciara making some electromagnets and stuff for bells. Making good bells proves both that the bell can be built, and that the electromagnets are strong enough to move the stepping wheels, and that the brass spring also works. I have already made electromagnets that are in the wind turbine, so it is a 'solved problem'. It just takes time and is boring to do. Even if we use the thinnest Alfheimr made copper wire, it is not optimal and it will draw more current than desired, but should work well for most electromechanics even though it will be unnecessarily strong.

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There is a bit of change as Asta returns to making her globe now that the King is no longer visiting, and Merchant Benti and Navigator Bjarnhedin seem to have learned enough from the Sextant and North arrow for their intended purpose during their forthcoming long journey. Asta is allowed to continue, and Jane starts training with Hillevi and Gunhild. Caecilia just went to take a hot bath where I told her to take time to enjoy herself, so Ciara distracts the staff, and Kari and Alith help me to quickly get the big wooden cross down into the secret room. We also move a bed, a cupboard, two wall version of oil lamps and take two prepared simple wooden doors and a bunch of planks, because I will have to do the finishing work myself. Now that it has been moved down, I can block the hidden door, ie the shelf between the semi-secret rooms with the secret rooms, but will do as much as I can before then with sound-absorbing bags etc.

I ask them to leave me alone, and try to keep Jane and Caecilia away from this part of the house for the next hour, while I try to figure out how everything should be securely attached, and first of is the doors. They made extra holes and mountings when they built the basement, but not everywhere I need it, so I'll try with a stone drill and hammer. That will be 'fun'. I ask Kari to sit in the library and listen while Ciara sits on the mezzanine sofa while I try to talk and shout a few things to see what they hear, and also try a few strikes with the stone drill.

The stone drill is heard but sounds weird, but I should be careful when I do the drilling to avoid curiosity. Basically when Jane and others are not in the house. Just speech isn't heard at all, lower shouts are faintly heard in the library but the source can not be determined, and loud cries are also faintly heard at the mezzanine's sofa.

Jane keeps on practising, and Caecilia is sent on a couple of errants. So I stand there in the light of the oil lamp, with hearing protection, eye protection and an impromptu respirator and starts to make a hole in the wall.

Limited sound attenuation will be better than nothing, and I will first try just stacking sawdust sacks and thick cloth. I need to know how much of a difference it makes before making something heavier. That door will probably never open except in an emergency. If I need to use that escape route, and then I can just toss the few sacks aside, and release the hooks that hold the shelf that acts as a hidden door to the semi-secret basement under the mezzanine. I will also use cloth around the doors and thick wool tapestries on the walls and ceiling to soundproof hard surfaces so it doesn't echo so much, and as an additional sound barrier. I had intended to use the secret room under the library as Kari's dungeon, but it is better to use the larger and darker space under the dining room, because then it will be easier to hide. If someone finds the secret passage and room, they will only find a quite boring secret library instead of the dungeon, and the library will work as extra sound proofing. It will be almost pitch black in there, but it doesn't matter because we will still need one or two oil lamps when we are there, just like in the secret library. I will install a couple of LEDs in the passage as stair light with toggle switches above and below, so it will be easier and safer and help finding and lighting the oil lamp.

Kari lets me know that the time is up, so I tidy up and then go and wash myself. Kari is excited and worked up about the project, so we have that shower together. She understand that it will take time to complete it all. Construction will happen when it is appropriate, and I feel like doing it. This isn't a prioritized project for me, and I plan to extend the construction time even though Kari won't like it. However, I have a very willing ally in Kari who is adamant that it is done as discreetly as possible, and Ciara does what I ask her to do without asking and keeps quiet about things. I trust Alith will keep important secrets to everyone. Well, Ciara might be an exception. Alith has more muscle than the other two combined, but I don't want her to build anything; she is not a worker, and it's enough that she keeps track of the other guards. All the guards know that they should avoid going down to the secret rooms unless they have to, and the east part will get a secret door too. A secret that is used too much won't stay a secret for long. There is far too many people here already.

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Iselin really wants to learn more about electricity and the maid systems construction, so we will have more lessons when she returns. I look forward to teaching her as much as I can about electromechanics, because someone must know it well in the future. Preferably better than I do. It's late as both me and Iselin are in a 'I just need to ...' work crunch and neither of us wants to put the work aside, even though Caecilia tries to remind us that Kari is waiting for me on the bedroom sofa. Finally, Kari is tired of waiting, and demonstratively sits down and just watch us work. Her passive-aggressive manner makes both of us ashamed because I literally think this work is more important than joining her in my bed, so I just put the work aside and after a quick trip to the toilet we go to my bedroom, to cuddle and sleep.