You can't just write to an I2C bus. The SCL line is an output from the master (Pi) but the SDA line is an input and an output.
The LCD should not have pull-ups to 5V on board but many do. Perhaps connect it to 5V and ground and then measure the voltage on the LCD's SDA pin. If it's 5V you definitely should use a level converter.
ILI9341 SPI 2.8" Touch TFT LCD Arduino Shield
Rpi3B+ OK? How to connect?
Yes, it is OK to use the ILI9341 Arduino Shield for Rpi. The following is the wiring for using SPI mode interface.
ILI9341 Touch LCD Arduino/STM32 Shield to Rpi3B+ GPIO Wiring V0.1
The following GitHub driver by juj has a comprehensive tutorial ...
It's working with my zero. However you will need to adjust the settings to use the entire screen, just researching that now.
The Kuman screen (which should come with the proper cable) is:
Kuman Capacitive 7" inch Touch Screen TFT LCD module HDMI 800x480 for Raspberry Pi 2 and RPi 1 Model B B+ BB BLACK SC7B
This page helped: 7-Inch-800x480 Display Kit(...
I assume you are talking about connecting a display on the GPIO of the PI.
Here are some speed benchmarks for the GPIOS: github page, and one can toggle a GPIO on the PI 3 at 65.8Mhz.
This is the speed for toggling one bit. If you want to drive a 8-bit parallel bus, you will need to drive the 8-bits of data + the control bits (at least the ...
If its one of the standard i2c 16x2 controllers it should have 3 pairs of address pads labelled A0,A1,A2. Jumping these according to the table below changes the i2c address.
I'm sure there are many, many ways of doing this but one of the easiest would be to create a GUI with python's built in tkinter module. Size the GUI window to the size of the LCD screen and when the IR signal name is received, code a label with name received to be displayed on the GUI.
It looks like a HD44780 device to me, a standard LCD parallel display which needs multiple GPIO (probably 8 if driven in 4 bit mode).
See https://www.arduino.cc/en/Tutorial/HelloWorld as an example interface.
SPI would not be suitiable.
Based on the pinout of the DS screen, there isn's a controller for the display, it appears to be a parallel RGB display. It would be a significant task to design a driver for it to be able to attach to a RasPi.
Read the last part of the Step 3 from RAEDME.md file of the GitHub repo you are referring to.
If you need to switch back to the traditional HDMI display
Login into your pi using ssh and cd to the location where you downloaded the driver and executed ./LCDxx-show previously and run the command sudo ./LCD-hdmi
With the recent Raspbian releases from raspberryi.org the pi user may be added as a member of the gpio, i2c, and spi groups, to grant access to those peripherals.
You don't mention the operating system you are using.
Try the following then logout and log back in for it to take effect.
sudo adduser pi i2c
Rpi can no longer boot after installing wrong LCD driver. How to fix?
A quick and dirty fix is:
Use a new SD card with a freshly downloaded Raspbian image, without any new LCD driver installed.
Then install your correct LCD driver.
You can fiddle with the Raspbian config files to remove wrongly ...
npm install raspi-sensors
npm install node-dht-sensor
That first library was last updated three years ago, so as is typical with the Pi (and Linux) you may deal with some compatibility challenges, while node-dht-sensor was updated two months ago. You can search the npm repository for other modules ...
If I understand correctly, this is not a Pi problem, but a C programming issue.
In C printf (and variants), %d means 'Output an integer' - which is what you are getting.
You need %f to output a float, or a double. If you only want one decimal point, use %.1f:
mylcd.lcd_display_string(“Pressure: %.1f%s hPa” % (pressure,chr(32)), 4)
There is lots of help ...
turn itself off when the room is dark. So now I need something to check a light sensor and control screen brightness.
In this part, you need to do the next two steps.
First. Buy a BH1750FVI I2C sensor and configure this light sensor hardware to the RPi by this link - Using the BH1750FVI I2C Digital Light Sensor.
Next. For the brightness control ...
Although your question does not make it clear how the display is connected I guess I²C. Like most devices on Amazon there is no meaningful documentation.
It is quite safe to connect to a 5V powered I²C device provided it has no pullups to 5V. The Pi has on-board I²C pullups to 3.3V.
I²C outputs are open-drain and you can safely connect devices to the Pi (...
The address of the board connected to your Pi is 27(hex) and not 20(hex).
The row shows the most significant digit and the column shows the least significant digit of the address in hex.
Going by Amazon, this is the default for the PCF8574T chipset on this board but looking at the pictures, one of the interface cards have a set of three address pins that ...
Waveshare have a wiki that explains how to connect this to a Pi 4 in English at this site here.
Basically, fit the HAT and change config.txt to read:
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dpi_timings=1024 0 0 0 88 600 0 0 0 0 0 0 0 60 0 26000000 6
I'm now certain there is an issue with the backpack or board.
After further inspection, I noticed that the plastic insulation at the base of the ground pin on the backpack and on the LCD board appear to be damaged. It looks like it was shorted. It could have been me, but I doubt it as I was very careful in wiring, especially as I know the damage that can be ...
On the breadboard all the 5V connections are in series with a single 5V pin
No they're not, they are in parallel.
They were using same 5v source but the current draw will be shared by those connected components.
You can just try it with Pi Zero.
Those HD44780 driven LCDs don't have reverse characters in their character set. If yours is displaying black text on the background, you are stuck with that.
— Well, you could undo the display frame and flip the polarizer, but most times, it's glued onto the glass. It's up to you if you find it worth a try. —
You end up with blue text on black then, of ...
Both way you described (either using a potentiometer as a voltage divider, or connecting a resistor between the contrast control pin (Vo) and ground) are valid configuration. The contrast of the LCD is determined by the voltage (VLCD) between the Vcc and Vo. When terminating the Vo with a resistor to the ground, the internal impedance between Vcc and Vo ...
Your question is not really answerable without details of the internal circuitry of the display.
Assuming you are using the actual device you linked just wire it as described.
Connecting the potentiometer as described is applying a variable voltage, between 5V and 0V to the contrast pin.
The display almost certainly has some active circuitry controlling ...
Try to change the rows of ui file:
<string notr="true">background-image: url(:/bmps/beldan.bmp);</string>
<string notr="true">background-image: url(beldan.bmp);</string>
Reading the code you posted I think that the .jpg and ...
Add to config.txt:
This is presuming the LCD is attached by DSI ribbon cable. That should also rotate the touch coordinates too.
1 = 90°
2 = 180°
3 = 270°
so the solution to this problem was very simple, in the HDMI connector had some dust build up, I deciced that i didn't do anything wrong, drivers where installed I knew that HDMI out works and that the cable was okay, So i tried, with special degreaser, to clean the whole unit, including the connector, and as expected the Display turned on.
welcome to an ...
I found this thread.
I tested the solution between two of my personal computers, both running Linux.
To find out the value of $DISPLAY, use a keyboard hooked directly to the pi. Then in the terminal type echo $DISPLAY
The value will probably be :0.0
Then once you ssh into the pi, type
(but replace the :0.0 with whatever value the echo $...