Thursday 15 December 2016

Dew Heater Controller

I am going to claim that I have all the parts now for building the Dew Heater Controller, to keep my camera lens or telescope clear. I say 'going to' as the OLED display I have has more pins than expected, and im not sure it is actually build for I2C control, and not one of the SPI configurations. There are what look like resistor/jumper instructions on it but they seem a bit vague! It looks like it might be set up for 3 wire SPI, but I cant tell for sure yet.

The project I am recreating is this one here Arduino based Dew Heater which uses an Arduino Nano to read a combined temperature/humidity sensor (the DHT22) and a digital thermometer chip (DS18), to calculate dewpoint and to measure the heating element. A small MOSFET driver module allows PWM control of the dew heater strap, and a 0.96" OLED I2C display shows me what its doing.

Tomorrow I will connect up the Arduino Nano and the OLED, and program it up. If I get the wiring and config right then I should at least get a display! And i'll be able to build on from there.

The big astronomical event, the Geminids meteor shower, is this week, the peak being yesterday. It would have made no difference having the dew heater already built, as in true fashion with the British weather I cant see the bloody sky and havent for several days!

On a more positive note, I did manage to get out for a short session on my newly secured metal detecting permission this morning. I didnt have long since I had an important phone call at lunchtime and then meeting an old work mate for tea, cake and moaning in the afternoon. It was a bit too wet really, very muddy, but it gave me chance to try out an Android based tracking app called 'Tect-o-track' which is so good I have just battled Google Play's poorly designed log-in screens to buy the full version (at a bank-raiding £3). Sadly I didnt realise it wouldnt transfer todays track and finds data from the Lite version! So the app doesnt have the details of the partial Thimble find from today.

Since I will be soldering tomorrow, I'll complete the remaining U3S LPF modules as well. I have the official case for this beacon on order on the slow boat from China. Ive also ordered yet another OLED display, this time one specifically I2C (it only has the four pins Vcc, GND, SDA and SCL). Ive had no luck with these damn displays, and had to endure a fight with a previous seller to get a refund.

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