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I’m rolling my own home security system for pennies on the dollar (and lots and lots of time, but this kind of stuff is fun to me). Here’s what I ended up with for the kitchen. It controls three distinct lighting zones and three entry points (two doors and one window). It has its own captive portal for network/LED/sensor configuration (using Autoconnect) and it’s fully connected. So far it’s testing out pretty well. Here are the notable parts:

  1. ESP-12F ($1.09 from Aliexpress). This is the brain — the venerable ESP8266 module, with some custom code to control the lights, sensors, and communications. I used pins 5, 4, and 15 (with a 10K to ground) as PWM outputs, and pins 12, 13, and 14 as inputs. I broke out pins EN and 0, as well as VCC and GND and soldered up the wires so I could re-insert it into the programmer in case the OTA updates failed.
  1. Cat-5E network cable (free, on hand). I use this stuff a lot. I used all eight wires in the cable, plus a couple more for VCC and GND.
  2. Resistor Header (a couple cents). I broke out EN and pin 0 so I could place 10K resistors and remove them again if necessary to program.
  3. Dual MOSFET Trigger ($0.84 at Aliexpress). This triggers with 3.3V and drives up to 36V, 400W — plenty for each of my three 12V LED lighting zones. There’s one of these per output channel. The one on pin 15 also contains a 10K resister to ground, which is necessary for normal operation.
  4. Mini DC Step-down Buck Converter, 3A ($0.50 on eBay). This takes the power from the 12V LED power supply and efficiently converts it down to the ~3.3V operating voltage of the ESP-12F. I originally planned on using a linear regulator thinking that this might cause some interference with the ESP, but that turned out to not be a problem. (The AMS 1117 regulator would have probably run hot, but not too hot.)
  5. Power (free, on hand). This connects to the 12V power supply. I used green for 12V because that’s what I had on hand.
  6. Input Sensor Header (free, on hand). This breaks out the three input pins in a 2×3 header, once side of which is all GND.
  7. Output Header (free, on hand). This breaks out the three output pins in a 2×3 header, once side of which is all GND.
  8. Removable 10K resistor (pennies). The third output channel MOSFET driver has this resistor soldered on, but it basically takes pin 15 low, which is required for normal operation.

Here’s how I planned out the wiring and headers:

This is a single month of a large collection of letters from Lotte, who lived in northern Germany, to her boyfriend Ernst, who served on the SMS Gneisenau before WWI (though these letters start after that ship had already been sunk). For details and links to other months in this collection, visit the index page for this collection. This month includes 8 letters in 33 images. 

March 1, 1917

March 4, 1917

March 8, 1917

March 11, 1917

March 17, 1917

March 20, 1917

March 22, 1917

March 29, 1917

This is a single month of a large collection of letters from Lotte, who lived in northern Germany, to her boyfriend Ernst, who served on the SMS Gneisenau before WWI (though these letters start after that ship had already been sunk). For details and links to other months in this collection, visit the index page for this collection. This month includes 7 letters in 29 images. 

February 1, 1917

February 4, 1917

February 8, 1917

February 15, 1917

February 20, 1917

February 22, 1917

February 28, 1917

This is a single month of a large collection of letters from Lotte, who lived in northern Germany, to her boyfriend Ernst, who served on the SMS Gneisenau before WWI (though these letters start after that ship had already been sunk). For details and links to other months in this collection, visit the index page for this collection. This month includes 7 letters in 23 images. 

January 3, 1917

January 7, 1917

January 11, 1917

January 15, 1917

January 18, 1917

January 22, 1917

January 29, 1917

This is a single month of a large collection of letters from Lotte, who lived in northern Germany, to her boyfriend Ernst, who served on the SMS Gneisenau before WWI (though these letters start after that ship had already been sunk). For details and links to other months in this collection, visit the index page for this collection. This month includes 8 letters in 28 images. 

December 7, 1916

December 14, 1916

December 18, 1916

December 21, 1916

December 22, 1916

December 25, 1916

December 28, 1916

December 29, 1916

This is a single month of a large collection of letters from Lotte, who lived in northern Germany, to her boyfriend Ernst, who served on the SMS Gneisenau before WWI (though these letters start after that ship had already been sunk). For details and links to other months in this collection, visit the index page for this collection. This month includes 8 letters in 26 images. 

November 3, 1916

November 6, 1916

November 8, 1916

November 13, 1916

November 16, 1916

November 21, 1916

November 23, 1916

November 29, 1916

This is a single month of a large collection of letters from Lotte, who lived in northern Germany, to her boyfriend Ernst, who served on the SMS Gneisenau before WWI (though these letters start after that ship had already been sunk). For details and links to other months in this collection, visit the index page for this collection. This month includes 7 letters in 24 images. 

October 1, 1916

October 5, 1916

October 10, 1916

October 15, 1916

October 19, 1916

October 22, 1916

October 26, 1916

This is a single month of a large collection of letters from Lotte, who lived in northern Germany, to her boyfriend Ernst, who served on the SMS Gneisenau before WWI (though these letters start after that ship had already been sunk). For details and links to other months in this collection, visit the index page for this collection. This month includes 9 letters in 30 images. 

September 3, 1916

September 7, 1916

September 11, 1916

September 12, 1916

September 18, 1916

September 21, 1916

September 24, 1916

September 28, 1916, Letter 1

September 28, 1916, Letter 2

This is a single month of a large collection of letters from Lotte, who lived in northern Germany, to her boyfriend Ernst, who served on the SMS Gneisenau before WWI (though these letters start after that ship had already been sunk). For details and links to other months in this collection, visit the index page for this collection. This month includes 11 letters in 26 images. 

August 2, 1916

August 7, 1916

August 9, 1916

August 11, 1916

August 16, 1916

August 18, 1916

August 20, 1916

August 22, 1916

August 25, 1916

August 28, 1916

August 30, 1916

This is a single month of a large collection of letters from Lotte, who lived in northern Germany, to her boyfriend Ernst, who served on the SMS Gneisenau before WWI (though these letters start after that ship had already been sunk). For details and links to other months in this collection, visit the index page for this collection. This month includes 11 letters in 26 images. 

July 5, 1916

July 9, 1916

July 13, 1916

July 17, 1916

July 18, 1916

July 20, 1916

July 23, 1916

July 25, 1916

July 26, 1916

July 30, 1916

July 31, 1916

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