Boat Ventilator Control

I've had this in place for a week or two now, it's working well. I updated to the new (sleep mode) release yesterday and so far, so good (I have a breadboard version at home that has had a bit more testing).

I'm publishing this now and will see how it works over the rest of the season.

I may return to it since the PCB is not brilliantly laid out, and I'd like to reduce power even further by powering the DHT11 off of one of the ATtiny's unused digital pins.

I kind of forgot a flyback diode when designing this, I did remember and the Unit I built has a 1N4007 soldered underneath across the +Ve and Fan terminals of the power connector.

I wanted to integrate it into the design, and I needed to fix a path probelem with the KiKad libraries for the sensor and DigiSpark, so I sat down and did a minor update on the PCB design. I dont intend to make this, but it looks fine. Also.: all the resistors are now flat on the board, they interfered with the case before.

I updated the schematic to add some notes and correct a badly labelled pin.

So, this is now installed and running in my boat

And I have spent some time refactoring the archive, and updating the documentation/readme's 

It's still not perfect, but should be easier to navigate and understand.

I will come back to this later since I still want to use an interrupt/timer for the primary sleep loop. Currently I just use a delay(), in idle mode the Digispark is only drawing a couple of mA.

I had a sudden burst of enthusiasm and finished this. I will be installing and testing this later. today The github repo needs some love etc.

From here:

https://forum.arduino.cc/index.php?topic=248576.0

Looks like this could solve a lot of testing headaches. If it works on my Uno.

I might extend it so I can simply pass values via the serial interface.

I had time recently to look at the Interrupt routines I want to use; got a couple of ATTiny examples working, one for timer and the other for a pin interrupt.

I will use sleep mode for the times between readings, but one of the relatively hight power modes that leave the PWM running. I might investigate using super low power mode for battery low conditions, in these modes even the PWM is off, but if the fan is running I need to limit sleep mode to one of the mid states.

I now need to define the main control loop; and implement it.

• One reading every 30S and then decide how to set fan.
• Power Control
  • Vmin->11.8V : Powersave mode; no activity, wake every 30s to take and process a voltage reading. Ignore button
  • 11.8->12.6V : Low Power Mode(s); start running the fan; limit max speed. respect quiet/off overrides
  • 12.6->Vmax : Full power mode. respect quiet/off overrides
• Fan Control
  • Need to think about this
• User Control
  • Off/Quiet/Idle
• Average readings; discard outliers
• Testing will be tricky.. I'll need to 'fake it' somehow for the humidity/temp readings.
• I'd like to use interrupts and have the controller sleep between readings/decisions.