An excellent way to stay warm while camping/overlanding on a tight electrical energy budget is with a 12V electric blanket. With a blanket such as this one under a sleeping bag, you can stay fairly warm. However, these blankets don't typically come with temperature control and you can easily overheat a couple hours after power on. In addition to it being uncomfortable, there's power being wasted here to achieve a comfortable temperature. The electric blanket controller uses a MOSFET as a switch to apply a duty cycle to the power coming into the blanket, giving users a choice between different levels of heat.

• Efficient - as most users are using 12V electric blankets off grid, it's important that the controller doesn't dissipate much power
• Easy to use - no modifications to the blankets or car power port, plug and play
• Replicable - so more overlanders can stop overheating with these blankets and save energy

• [ x ] Find appropriate hardware for controller
• [ x ] Test hardware and find duty cycle
• [ x ] Create PCB
• [ x ] Write firmware
• [ x ] Test firmware
• [ x ] Build controller on real PCB with v1.0.0 firmware
• [ x ] Design a 3D printed case

Flash the .ino file using your favorite ATTiny programmer. I didn't have one handy so ended up using an Arduino Uno to flash the ATTiny. The ATTiny needs to run at 1 MHz clock for this project, which should be the default from factory. The hardware directory contains the circuit board schematic and board files in pcb as well as a 3D printed case with tight and loose tolerances to account for the variablility in 3D printers.

Distributed under the MIT License. See LICENSE.txt for more information.