Gina

Still working fine.

Second test :- Diode current reduced to 5mA by dropping the PSU voltage. Collector voltage with PLA absent was 2.3v and at 2-4mm gave 0.16v. Since I don't want to leave the sensors open to the damp I shall have to test with a dark background. I think I have some FLO black velour for lining scopes, though black paper or matte black paint may do. I'll do more testing tomorrow.

Didn't have a 12KΩ so used 10K. Voltage across the 3 diodes was 2.6v. Without plastic (white PLA) the collector was at 1.9v with plastic at 2-3mm voltage was 0.18v. That's a pretty good change.

Swapped the 2 10g silica gel packs for fresh ones. The beads weren't green but were quite a dark orange. Now refreshing in the microwave for a few minutes. That was a week with lots of wet weather so that's not bad.

Lovely.

For testing I can connect 4 diodes in series and connect to 12v from my bench PSU through a 680Ω resistor. Since the diodes drop around 1.1v, 3 of them will be 3.3v so I can connect from there to a transistor collector with a 12KΩ resistor and check collector voltage.

Maybe you haven't tried feeding 12v into it 😀

Been looking at the datasheet for the TCRT5000L reflective optical sensor. With 20mm through the diode it gives 1mA of collector current in the transistor which is more than enough. Mind you, it does depend on the reflectivity of the surface and that's where experimenting is required. I'm thinking of going for 10ma diode current giving around 0.5ma collector current. The volt drop in the diode shows 1.1v so with 4 in series that's 4.4v. If I run off 12v that leaves 7.6v for a series resistor = 750 ohms. 680 is the nearest preferred value. For the detector transistor, I think I'll work on 0.25mA as a start. If I run it from 3.3v, 12K should let it saturate at 0.4v VCE. I have yet to look at the ESP32 datasheet to see what analogue voltage it takes but mostly this uses 3.3v so I assume that's the maximum.

Here a screenshot of the Gray code disk model.

Sensors have arrived so now I'll set up a test rig. I think optical is favourite as only 4 sensors needed. OTOH the emitter diodes need a fair amount of current. I would prefer Hall devices but ATM I can't see how to use fewer than 8 of them. Optical is more accurate though.

The ESP32 has arrived and it isn't all that big - just over 1" wide and 2" long (28mm x 50mm). Now I'm waiting for the optical and Hall sensors.

I agree about the capacitance - it was just a thought but I can see it wouldn't work. I haven't found debounce needed with Hall devices but I can see a problem if I used Hall switches with the wind vane as that can "wobble" due to wind turbulence. The Hall devices have a Schmitt trigger circuit built in so don't suffer bounce with a fairly steady increase or decrease in magnetic flux. I have examined the output on an oscilloscope and there was no "bounce" - just a clean, square pulse shape. I used reed switches in previous wind vanes but did find the the magnet was attracted to the reeds and would "cog" as it moved in a light breeze and although the magnet was spaced to give an overlap representing 16 directions, statistical analysis showed a distinct preference for the 8 main compass points. I did a lot of statistical analysis on my weather stations years ago. With the wind vane data, it is first necessary to decode the Gray code to binary. Then the sampled data can either be added into a Rose Chart or converted to an average direction using Consensus Averaging.

I've ordered the IZOKEE NodeMCU Module ESP8266 ESP-12E from Amazon. Due to arrive tomorrow.

Found this If these pins measure capacitance as seems the case, I think I could make a Gray code plate as a variable capacitor in conjunction with small metal plates as the sensors.

Looking at the GPIO pins I see 10 Capacitive sensing GPIOs. Must investigate. Wonder if these could be used with the wind vane.

As for sensors, the anemometer has a single Hall effect switch with 3 miniature magnets on the rotor. I estimated this as giving 1pps per mpg of wind speed. The wind vane will probably use 4 reflective optical sensors with Gray code disc giving 16 directions and 4 bits of data. This needs analogue inputs as the phototransistor current varies. OTOH I will be trying 8 Hall switches with one magnet on the rotor with overlapping operation like the cheap wind vanes use reed switches. This would then use 8 digital inputs. Both systems have their pros and cons. If anyone has any comments on these ideas I would be glad to see them.

BTW, does the orientation of the ESPs matter or are the aerials omnidirectional.

Thanks everyone - good news. I like the smaller size for mounting atop the wind sensors mast. Think I'll order one - should arrive tomorrow. The ESP32 is due to arrive around 1pm by DPD, the Hall devices and optical sensors by Amazon currently saying between 3pm and 6pm.

Reading the instructions, how to use on the Amazon site it mention Win32 and Win64 so may need windows and I have Linux only so I'm doubtful of this version.

This is an ESP8266 with lots of pins but smaller than the ESP32.

Haven't decided on the sensors yet - I have some experimenting to do.

The ESP32 seems like overkill but the ESP8266 is not enough so overkill it is! OTOH I'll look at ESP8266 versions with more pins and see if one would serve for the wind sensors.

That would be well adequate

Yes, that's certainly a point.

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