Quantity   Component name
1 × Raspberry Pi https://www.adafruit.com/products/2885 Zero is preferable for compactness
1 × USB Wifi Adapter with external antenna Testing different cards. My go-to is an old Realtek running rt73usb. Anyone know this chipset? http://www.aliexpress.com/item/Mini-PC-wifi-adapter-150M-USB-WiFi-antenna-Wireless-Computer-Network-Card-802-11n-g/32435687070.html
1 × SMA Pigtail http://www.aliexpress.com/item/New-Arrival-10cm-SMA-Male-Plug-to-SMA-Female-Jack-Bulkhead-Right-Angle-Pigtail-Cable-RG316/32385968187.html
1 × USB OTG Adapter http://www.aliexpress.com/item/USB-OTG-A-Female-to-Micro-USB-5-Pin-Male-Adapter-Cable-for-Samsung-Wholesale/1669106671.html
1 × 5V Power Supply Still researching...
1 × Batterie(s) Still researching...
1 × Power switch Any microswitch
1 × MicroSD Card (8GB+ recommended)
1 × Mini HDMI adapter and USB hub helpful for setup You could probably skip this if you have a USB to ethernet adapter.
1 × RTC If you are going to have your PI insert occasional TTS announcements, you might want to provide the time. http://www.aliexpress.com/item/DIY-DS3231-Precision-RTC-Clock-Memory-Module-for-Arduino-Raspberry-Pi/32425147956.html