I have always had some interest in cryptology and secret stuff like that. I did read up on how the German Enigma worked before I ended high school so it's not precisely a new idea that I want to make a enigma replica of some kind.
Yes, it does exist several in various degree of complexity already but the interesting part isn't to have one, it's to make one so they don't count (and they all have something I don't like or missing something I want).
My plan is to make an electronic Enigma replica that on the outside looks very much like the original - as far as cost allows.
Inside it will of course be all electronic with LEDs, alphanumeric display for rotors and so on.
I have a ruff plan on how to do it in my head and as of today I have ordered a pile of parts from ebay and aliexpress so in a month or two I should be able to start assembly.
My plan is to have
* one top PCB with the alphanumeric display, the rotors (made of rotary pulse encoders and a 3D printed wheel), switches and an arduino clone.
* next PCB is just the light board with it's 26 LEDs
* next PCB is the keyboard with it's 26 Keys
* last PCB is the front side plug board with sockets and a little of smarts in it
The boards are connected with a flat cable working as a bus
By splitting up the parts design of on part can be changed without impacting the rest. The keys can be simple tactile ones with a small cap or something with a 3D printed cap that looks like original.
It also makes it easier to make it look more realistic by having the boards at different levels
I would love to have real wheels/rotors that you can take out and switch around. I have some ideas on how to make it possible but it's not that easy or cheap to implement so maybe some future version will come with that.
It's of course a ton of things to think of in order to make this project and that is just one of this things that makes it's interesting to work on it.
My current issues is how to make the PCB and learn 3D printing software. Given that I want it to be open I want to use open source tools to create it also (plus that free version of eagles max pcb size is way less than what I need) I have decided to use KiCad for my PCB but since I never used that before I need to learn it.
Back working on the temp sensor that I started in http://lpaseen.blogspot.ca/2014/11/temperature-humidity-monitoring.html
Two prototypes have now been running over 5months on same battery so my fear that I have to replace batteries every 2 weeks is gone.
With that in mind I moved on and made a PCB to place all parts there. First try came out ok.
I then put it in a small box with 2xAA battery. The booster is a separate board and that is something I don't like. Will probably make another board+box and use 3xAAA in it so I don't need a booster.
It's a lot left to desire for any kind of final version. The booster is annoying and I wonder if it's better to run off 3 batteries instead. The advantage of the booster is that it suppose to work as long as the two batteries together gives more than 0.9v. On the other hand, it takes power and space. I don't have a good enough multimeter to properly measure how much it takes so I can't test it that way. What I do know is that the sensor with 3xAAA NiMH and 3.1V left is still running after 5 months. The one with 2xAA NiMH and booster been on for almost 6 months and with 2.45V left I expect it to run a bit longer.
Besides battery my other issue is wireless range, was hoping for a bit more than the size of the house but that seems to be tricky. If I put the receiver in the basement and transmitter in attic it doesn't work so I moved the receiver to the middle of the house and then I can get my (way to high) attic temp.
I'm considering making another version without a arduino board, just the atmel chip (which one, atmel328p, attiny85 or something else?), SMD, ISP connector and voltage booster onboard (with the option to not populate it if going with 3XAAA). If so I can of course no longer get a way with toner method to make my own PCB and need to order it from somewhere, http://dirtypcbs.com/ that has a $14 protopack for 10 5cmx5cm boards looks interesting.
Next we have the presentation side, right now it's just storing all values in a .csv file. To get something going I'm trying to upload about one week of data to plot.ly so now I have temp&humidity at https://plot.ly/~lpaseen/306 and battery level at https://plot.ly/~lpaseen/309