Tuesday, June 9, 2020

Day 123,124, 125 - More Techy Stuff...

Sunday (123) - I tried my ESP-32S board with the IRF520 MOSFET as a dimmer for 3.6watts of LED under cabinet reading lights. At first, I had the V- output be the same as chassis ground and the lights came on immediately with the microprocessor powered off. I then wired the light “ground” into the V- output of the MOSFET. This worked and through Home Assistant the light could be controlled including dimming. The problem was that full bright wasn’t what it should be meaning that there was insufficient current through the MOSFET. The switching voltage was just too low. BTW, the reason for the MOSFET is that LED dimming is done using pulse-width modulation aka PWM. That is, by varying the duty cycle of a square wave, you can change how long the LED is actually lit. The frequency is too high for your eye to see. The frequency is one of the parameters you have control over in the ESPHome configuration.

Now, I’m shopping for some logic level converters which would convert the 3.3v output of the ESP-32S to 5v for the signal input of the ISF520. Due to inadequate research on my part, I didn’t learn that the digital I/O ports were 3.3v until after I had ordered the IRF520 boards. I just assumed that it would be the same as a Raspberry Pi or an Arduino. The logic level converters are an easy fix though it means that this project will be “back burnered” for a while until we can receive packages again.

It has been windy since last night and it will continue into tomorrow. Even sitting here on concrete with our hydraulic jacks down, we can still feel (and hear) the wind.

Monday (124) - Maybe I should consider upgrading from the Pi 2 to the Pi 4. Most of the time the processor utilization is around 5% but when I'm doing firmware upgrades to the microprocessors, the CPU pegs and it takes quite a while. Especially since I'm thinking of expanding this "system".

Tuesday (125) - Another “packaging” project. This is going in the front-passenger storage bay. I already have PowerPole connectors for the LED awning lights. That is why I have two sets of power leads coming out of the box. One going to 12vdc and the other one for the awning lights. The blue thing sticking out of the box is a DHT11 low-resolution humidity/temperature sensor just so I know what the temperature is inside of the storage bay. The black wire is the DS18B20 temperature sensor that I’m going to stick out the back of the storage bay into the open space behind the fuel tank and across from the propane tank. The box will be finished after I hot glue the DHT11 and the OLED display in place. The display was added just because I had extras. It displays time and the outside temperature. I may play around with it and just display a large 40-point temperature. That may be more useful. The box is a water-tight junction box I ordered from Amazon.

I changed our next TT reservation this morning. We head to Chehalis, WA, on Sunday for just short of three weeks. Originally, this was when we were planning to go to Maui for a family reunion that Bridget was planning. The quarantine rules in Hawaii are more severe than Alaska so the reunion has been postponed.

Here is the box installed with a 42 point font for the temperature. I may need to modify it for temperatures over 100°F. We’ll see...

Actually, I just changed the formatting to get rid of the tenths of a degree. Now the font is fine…

No comments:

Post a Comment