Chipguy's Nano Breakout Board with Battery Power Control

Add your own Arduino Nano, and enjoy the breakout!   Power it via VIN(6-10V) or at the regulated 5V pin to keep it on full-time without power control. Power it on via BAT+/- (6-10V) to enable battery power control, which allows you to completely cut off battery power until any PWBUTTON is pressed. This is not a charging system and is for non-rechargeable/alkaline batteries only. Power is switched on when you connect any of the five PWBUTTONS to their common (which happens to be BAT+). After button release, power stays on as long as your sketch holds D7 high. You can read battery voltage via analogRead(A7). Range (0-1023) is 0-15V. You can read the state of PWBUTTONS via A0,A1,A2,A3,A6 if you solder the pads on the underside of the board enabling this. You can connect relays. The 10-pin headers along the side are meant to fit the 2, 4, and 8 blue relay packs made in China available on Amazon. You can connect an NRF24L01 radio if you add a 100uF capacitor to C1. CSN/CE are D9/D10. IRQ select via solder pads. Connect a piezo beeper, and send tones to it via tone() on D6. Connect an IR receiver, and receive IR commands via D8. Amazon sells a DS3231 real-time-clock that fits on the RTC pins and communicates over SDA/SCL. If you want to exceed 11V at VIN (or use the power control to switch power for external loads bigger than a relay pack): - remove U10 and replace it with an IRF9540N MOSFET (holes provided). - If you want to bypass Nano's voltage regulator (especially at higher voltages) you may want to add a 5-volt DD4012SB buck converter (and cut VIN pin from your Nano), holes are provided for this. - going above 15V? we'll overdrive Nano's pin A7 (voltage sense), cut that pin if going any higher than 15V.