Arduino - It Only Does Everything!

Several months ago a friend of mine really into making bread inquired about a possible solution for proving bread dough and making pre-ferment starters in the winter. You see, here in Canada winters are cold. Very cold. And heat isn’t free. Yeast likes to be in nice warm moist conditions, but my wallet likes to be in the cold with a thick sweater.

So the goal was to create an efficient device that monitors temperature and switches a heat source on/off as necessary to maintain a constant temperature inside of an enclosed space such as a camping cooler.

And here is the result! It’s based on the bare minimum circuitry needed for an Arduino compatible board and then builds on top of that; character LCD display, two buttons, DS18S20 temperature sensor, and a small relay for switching an AC lamp.

Source code, schematic, PCB layout

v1 PCB - component side

• source files from my git repo, or github
• see README file for ATmega flashing details
• v1 PCB artwork [PDF] for toner transfer or exposing pre-sensitized copper clad
• v1 schematic [PDF]

What’s inside

The doughduino deviates slightly from the Arduino on a breadboard; it does not have a power supply regulator so an external 5v supply is needed. I was pleasantly surprised to find that the guts from an old cell phone charger worked just fine (many chargers are 5 volt, 1 amp supplies).

Guts from a cell phone charger

Fully assembled internals

Assembled PCB with annotations

Questions/Comments

Feel free to post a comment or short questions below. If you need help please use the forums.

Hopefully this fixes the sporadic behavior people have reported with their LCD’s. It certainly fixes the problem with the two LCD’s I have tested.

I also added a schematic to the package. It just outlines where to connect VCC, GND and where to put the 10K pot.

Specifically, this version removes the hard coded delays after each command is sent to the LCD and checks the LCD’s busy flag. This is a cleaner approach and should mean that the library works more reliably with various LCD modules (hopefully). The setup method has been cleaned up as well to make initialization by instruction just work without any hacks.

Of course, this does mean that the RW pin on the LCD must be connected to the Arduino instead of connecting to ground.

As before, see the Arduino LCD Library page to get the latest version of the code.

Check out the Arduino LCD Library page for more details.

Here is a short video demonstrating an animation sample.