The Raspberry Pi Thread [5]

Pimoroni announced a new product today,,, not one I'll be getting . Grow – Pimoroni ,,,

Just redid my modified enviro+ code that I run on my Breakout Garden. I was using the 160x80 LCD and wanted to now use the 240x240. My two 160x80's now have headers soldered on and are plugged into the solderless breadboard on my bread board rig. That rig takes up a lot of space to just to display my pressure graph on. Now I can keep track on my headless breakout garden Pi, and on a slightly bigger display. With these storms on the way I want a quick way to see if the pressure is dropping, and how fast. I graph 2 hours across the screen.

If you go here, Enviro for Raspberry Pi - Monitor your world! – Pimoroni
You will see the Temperature graph on the display in the product picture. The Enviro code lets you cycle through and watch any "one" of temp, humidity, or pressure.
With a little editing that code will run on a breakout garden equivalent of a BME280 and that 160x80 display. That's the display you ordered for me. I have two now and with a third I can display all thee at the same time. Each graph on its own display.
I have temp and humidity working now, just have to add in pressure.
I got bored so I modified my single display code to show pressure on the 240x240 display I had just sitting there doing nothing. Now that my two 160x80's have headers soldered on I can no longer plug them into the breakout garden.
The original Enviro+ code samples really fast, once a second or more. Not what I wanted for my pressure graph. Mine samples and plots once every 60 seconds. Barometric Pressure changes very slowly over time so I made mine show a wider time frame .

I almost always have stuff in my cart. The Breakout Garden is just for testing if something will do what I want. No having to solder on a header to test it, if its breakout garden compatible of course. The mini SPI i2c was only 15 bucks. I'm going to get a second mini i2c only at some point, that will get me five i2c sockets and the one SPI. If the SPI were side by side instead of one behind the other on the Hat I would have gotten that instead of the mini.

One step forward, sort of kind of?
I've been playing around with my Barometric Pressure LCD graph display. One thing I wanted was a way to turn the display backlight off. So I can leave it running plotting data but be nice and dark at night when I'm asleep. Not lighting up the room its in etc.
Annoyingly Pimoroni codes it something like this.

Code:

disp = ST7789.ST7789(
    port=0,
    cs=ST7789.BG_SPI_CS_FRONT,  # BG_SPI_CSB_BACK or BG_SPI_CS_FRONT
    dc=9,
    backlight=18, # 18 for back BG slot, 19 for front BG slot
    rotation=90,
    spi_speed_hz=80 * 1000 * 1000

I had the cs= correct but the backlight= wrong, it should have been 19 not 18. The display still lights up though, but disp.set_backlight(0) doesn't work? Wrong pin is pulled low.
Once I fixed that the display turned off, half way there, lol. That's fine while the Pi is running the code. It will do some of what I wanted. If you also code in a shutdown though, that pin goes back to a floating state when the Pi shuts down and the display lights back up. Not the end of the world but another one of those gotchas just when you thought you had it beat.
It just means I have to unplug the power supply if and when I do a full shutdown. I may just wire in a switch that pulls the pin low and do it via hardware instead of software. The display won't know the difference.

I will hardly ever shut down the finale build so what I have now is usable. A switch wired to the backlight pin to ground it will work regardless of whether Raspbian is running or not so I'll probably go that route.