The following materials are needed to construct a Jam Sentry:
1x ESP8266 Huzzah breakout (https://www.adafruit.com/product/2471)
1x TSL2561 Luminosity Sensor (https://www.adafruit.com/product/439)
1x HMC5883L Magnetometer Board or LSM303 Magnetometer Board (https://www.amazon.com/gp/product/B0141UFZTU or https://www.adafruit.com/product/439) – Be sure the board says it is Adafruit compatible, some boards use a different I2C address and won’t work.
2x 3x6x2 miniature ball bearings (https://www.amazon.com/gp/product/B019F2ZH92)
1x stick of right angle male headers (https://smile.amazon.com/Single-40-pin-2-54mm-Header-Breadboard/dp/B01461DQ6S). You will also need a stick of straight male headers, but they come with the ESP8266 board)
2x really small screws to attach the cowling (M2x6mm) or similar. Only 2 screws are needed (https://smile.amazon.com/uxcell-Stainless-Phillips-Tapping-Screws/dp/B01KXTSW6Q). A #2×1/4″ screw works too (https://smile.amazon.com/Screws-Phillips-Stainless-Self-Tapping-Quantity/dp/B01CEZSQU4)
1x FTDI Serial Cable or USB to console cable (https://www.adafruit.com/product/70 or https://www.adafruit.com/product/954)
3/4″ heat shrink tubing (https://www.amazon.com/gp/product/B0053PYDFA)
4x male to male dupont cables (https://smile.amazon.com/Aukru-20cm-Breadboard-Arduino-Raspberry/dp/B019SX72CI), or you can just use 4 Female to Female jumper wires (https://smile.amazon.com/GenBasic-Female-Solderless-Breadboard-Prototyping/dp/B01L5ULRUA)
If you want to include the runout line triggering capability in the circuit then you will also need a 2N3904 transistor and a 66K 1/4 watt resistor.
The backplane circuit board can be ordered here. Unfortunately, each order is for 3 boards, but the total order including shipping is under $5.