Bill-of-material nitrox analyser
Button: https://www.aliexpress.com/item/829086699.html On/off switch: https://www.aliexpress.com/item/32879359719.html 9V battery clip: https://www.aliexpress.com/item/32672374771.html 9V battery Oxygen sensor (R22D) https://www.shearwater.com/wp-content/uploads/2012/08/r22d.pdf
PCB 29 x 44.8 mm (will be stack of screen - nano - main PCB - ADS1115 + connections): Arduino Nano: https://www.aliexpress.com/item/32848298184.html ADS1115: https://www.aliexpress.com/item/32672594709.html 0.96” OLED screen: https://www.aliexpress.com/item/32638662748.html SMB connector (for JJ cells): https://www.aliexpress.com/item/4000200190069.html Female header pins to raise OLED screen above Nano https://nz.rs-online.com/web/p/pcb-sockets/2518193/