Use to monitor voltage range and enable external controller (Arduino; Rpi; Stamp; etc). Triggers 5v / 1amp at Upper Limit; turns off at Lower Limit. Trigger will only fire upon reaching upper limit; and only release upon reaching lower limit.

Limits are set using resistors / Voltage Dividers.
Vin (Battery) can be 10 - 30 volt.
*Sample points / Voltage Dividers need to be 2v - 7v. Do not exceed 7v.

Examples which set sample points to 2.5volts: Upper Limit of 14.1 Volts: R4 = 4.4k , R5 = 1k Lower Limit of 12.7 Volts: R2 = 3.2k, R3 = 1k

Parts List: Shopping List

2 Screw terminal - 2 pins pins 2; package THT; hole size 1.0mm,0.508mm; pin spacing 0.1in (2.54mm)

3 Rectifier Diode type Rectifier; package 300 mil [THT]; part # COM-08589

1 Voltage Regulator chip 78005; package to220-igo; variant sink; voltage 5V; part # COM-00107

1 4.4kΩ Resistor bands 4; package THT; resistance 3.3kΩ; pin spacing 400 mil; tolerance ±5%

1 3.2kΩ Resistor bands 4; package THT; resistance 3.2kΩ; pin spacing 400 mil; tolerance ±5%

2 1kΩ Resistor bands 4; package THT; resistance 1kΩ; pin spacing 400 mil; tolerance ±5%

1 4.4kΩ Resistor bands 4; package THT; resistance 4.4kΩ; pin spacing 400 mil; tolerance ±5%

1 SN74LS21N type SN74LS21N; package DIP14 [THT]

Breadboard & Simulation Tested. Awaiting PCB