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2019-11-22 fredag v.47

Wooden Clock

Kod
Two four digit seven segment LED displays, one 1.2" and one 0.56", showing the time and the temperature. The displays will be cover by a thin veneer letting the light from the LED display shine through.

The start

The arduino with some LED shield that has worked as our bedroom clock had two big flaws, it didn't keep the time properly and it didn't compensate for normal and summer time. Should I get a better RTC? Should I bulid a DCF77 module? Maybe a WiFi shield that can fetch the time over NTP? Or maybe the simplest way is to use a Raspberry Pi Zero W instead? I went for the latter.

The first parts


The RasPIO interface along with a LDR and a thermistor arrives. The thermistor is of course going to be used for displaying the temperature. The LDR on the other hand will be used for automatically dimming the displays, if possible. The RasPIO is a board with an MCP3008 AD converter which will be used for reading the values from the two sensors.

The LED displays

After a while I found a company in England that sold Adafruits 1.2" and 0.56" four digit seven segment LED displays. The big one is going to be used for showing the time and the smaller one for displaying the temperature.
The frequency of the blinking colon isn't steady so I need to solve that. It could be the ugly sleep I inherited from the Adafruit example code that is causing this.