Golem

A open controller for electric kilns.

Firing/temperature profiles

A firing profile is described like this:

Segment number	Rate (°C / hr)	Target temperature (°C)	Segment time (min)	Hold target temperature (min)
1	100	250	150	0
2	200	850	180	0

and the same profile in JSON:

{
  "name" : "Raku",
  "1" : {
    "rate" : 100,
    "target" : 250,
    "hold" : 0
    },
  "2" : {
    "rate" : 200,
    "target" : 800,
    "hold" : 0
    }
}

but currently each profile is stored as a SPIFFS file like /prog/<profile name> and contains <rate>,<target>,<hold>{,<rate>,<target>,<hold>}, for example:

80,250,0,50,800,0

The last open profile and the state of that firing is stored in /state/current and contains:

<profile name>
<segment number>

If segment number is zero it means the firing profile is not running.

Temperature control and graphing

Temperature readings are taken every second. These sliding average over the last 5 seconds is shown as the live temperature. The average over one minute is added to the graph and used for determining if the relays should be on or off during the next minute. The graph on the TFT shows one Y-pixel per 50 degrees and one X-pixel per 3 minutes.

Hardware

ESP32
MAX31855 (MAX31855KASA+T)
K-type thermoucouple rated for atleast 1300 degrees
1.44 inch TFT (128x128px) (optional)
3 x Solid State Relays (one for each phase of the three phase 400VAC kiln)

Pinout

TFT RST  -> IO4
TFT CS   -> IO5
TFT DC   -> IO2
TFT CLK  -> IO18
TFT MOSI -> IO23
TFT MISO -> IO19

SD SCLK -> IO14
SD MOSI -> IO13
SD MISO -> IO12
SD CS   -> IO15

I2C SDA -> IO25
I2C SCL -> IO27
I2C CS  -> IO26

SSR     -> IO33
BTN 1   -> IO34
BTN 2   -> IO36

Temp sensor -> IO35

With help from https://drive.google.com/file/d/1gbKM7DA7PI7s1-ne_VomcjOrb0bE2TPZ/view and https://randomnerdtutorials.com/esp32-pinout-reference-gpios/

Hardware test setup:

User Interface

The user interface is served through a captive portal on the ESP and uses websockets and client side javascript. The user can;

perform CRUD operations on firing profiles
start and stop a firing profile
start and stop the kiln manually The AP name is "Golem-AP" and the password is "golgolem".

Todo

Valde Ionic med Vue utifrån dessa; https://betterprogramming.pub/react-native-vs-flutter-vs-ionic-46d3350f96ee https://www.codeinwp.com/blog/angular-vs-vue-vs-react

Add file browser for uploading, downloading, viewing and editing raw JSON-files. ACE might be a good editor to embed.