Quantity   Component name
1 × FE Electronics FE-5650A Opt 58 Rubidium Frequency Standard Used - Ebay
1 × Pololu 5V, 500mA Step-Down Voltage Regulator D24V5F5 https://www.pololu.com/product/2843
1 × DROK DC-DC 80W Auto Boost Buck Voltage Regulator Stabilizer 5A 3.3V-30V to 0.5V-33V LED Display https://www.amazon.com/gp/product/B01DXEU4KA
1 × TCA9548A I2C Multiplexer https://www.adafruit.com/product/2717
3 × Mercurry DS3231 AT24C32 IIC Module Precision Real Time Clock Memory Module https://www.amazon.com/gp/product/B01HGX8Q2W
1 × ATMEGA32U4 Mini Board http://www.gearbest.com/boards-shields/pp_226799.html
2 × LM2596S DC DC step down 5V-35V to 1.25V-30V Power Supply https://www.amazon.com/GERI-1-25V-30V-converter-Constant-Adjustable/dp/B013WKRDKE
1 × 32 Channel San Jose Navigation GPS 5Hz Receiver with Antenna https://www.sparkfun.com/products/retired/8266
1 × Scavenged Heat Sink/Fan - Cut down to fit Good luck on this one - perhaps a high power LED cooling heat sink? The fan is rated for 12V, but set for around 6V.
1 × Old HP Printer Power Brick ~ 18.5V (Many alternatives 5-30V...) Something efficient and stable - avoid really cheap switching supplies. Reliability matters here.
1 × Ancient Serial LCD module - Scott Edwards Electronics Serial Backpack attached to a surplus 4 line LCD character display. Circa 5V - Inverted serial interface - datasheet here: https://seetron.com/docs/bpk000mnl.pdf - LCD unknown origin... electronics goldmine perhaps?
1 × K2 Energy - 18650P LiFePo4 Battery http://www.k2battery.com/products-18650P.html