Asynchronous NodeJS module for controlling oled devices on the Raspbery Pi (including the SSD1306 and SH1106 OLED screens)
npm install oled-rpi-i2c-bus-async!npm version !downloads over month
Asynchronous OLED JS Pi over i2c-bus
========================
oled-rpi-i2c-bus, which itself is a fork of oled-js-pi. This version works through the i2c-bus package and does not use the i2c package.
i2c-bus package for improved performance and non-blocking operations.
dtoverlay=i2c-gpio,bus=3 to /boot.config.txt. The software I2C would be available on bus no 3
SDA is on pin GPIO23/BCM 16 and SCK is on pun GPIO24/BCM 18.
npm install oled-rpi-i2c-bus-async
SH1106, if you get an error:
"Error: , Remote I/O error"
`
You might have to lower the baudrate by adding the following line to /boot/config.txt and rebooting the Pi
`
dtparam=i2c_baudrate=10000
`
This is a known issue with Raspberry Pi as noted in Raspberry Pi I2C hardware bug. Alternatively, use software I2C.
I2C screens
Hook up I2C compatible oled to the Raspberry Pi. Pins: SDA and SCL
$3
`javascript
import i2c from 'i2c-bus';
import Oled from 'oled-rpi-i2c-bus-async';
const opts = {
width: 128,
height: 64,
address: 0x3D,
bus: 1,
driver: "SSD1306"
};
const setupOled = async () => {
try {
const i2cBus = await i2c.openPromisified(opts.bus);
const oled = new Oled(i2cBus, opts);
// do cool oled things here
} catch (err) {
console.error('Error:', err);
}
};
setupOled();
`
$3
Check your screen's documentation...
Available methods
$3
Fills the buffer with 'off' pixels (0x00). Optional bool argument specifies whether screen updates immediately with result. Default is true.
Usage:
`javascript
await oled.clearDisplay();
`
$3
Lowers the contrast on the display. This method takes one argument, a boolean. True for dimming, false to restore normal contrast.
Usage:
`javascript
await oled.dimDisplay(true);
`
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Inverts the pixels on the display. Black becomes white, white becomes black. This method takes one argument, a boolean. True for inverted state, false to restore normal pixel colors.
Usage:
`javascript
await oled.invertDisplay(true);
`
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Turns the display off.
Usage:
`javascript
await oled.turnOffDisplay();
`
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Turns the display on.
Usage:
`javascript
await oled.turnOnDisplay();
`
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Draws a pixel at a specified position on the display. This method takes one argument: a multi-dimensional array containing either one or more sets of pixels.
Each pixel needs an x position, a y position, and a color. Colors can be specified as either 0 for 'off' or black, and 1 or 255 for 'on' or white.
Optional bool as last argument specifies whether screen updates immediately with result. Default is true.
Usage:
`javascript
// draws 4 white pixels total
// format: [x, y, color]
await oled.drawPixel([
[128, 1, 1],
[128, 32, 1],
[128, 16, 1],
[64, 16, 1]
]);
`
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Draws a one pixel wide line.
Arguments:
+ int x0, y0 - start location of line
+ int x1, y1 - end location of line
+ int color - can be specified as either 0 for 'off' or black, and 1 or 255 for 'on' or white.
Optional bool as last argument specifies whether screen updates immediately with result. Default is true.
Usage:
`javascript
// args: (x0, y0, x1, y1, color)
await oled.drawLine(1, 1, 128, 32, 1);
`
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Draws a filled rectangle.
Arguments:
+ int x0, y0 - top left corner of rectangle
+ int w, h - width and height of rectangle
+ int color - can be specified as either 0 for 'off' or black, and 1 or 255 for 'on' or white.
Optional bool as last argument specifies whether screen updates immediately with result. Default is true.
Usage:
`javascript
// args: (x0, y0, x1, y1, color)
await oled.fillRect(1, 1, 10, 20, 1);
`
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Draws a bitmap using raw pixel data returned from an image parser. The image sourced must be monochrome, and indexed to only 2 colors. Resize the bitmap to your screen dimensions first. Using an image editor or ImageMagick might be required.
Optional bool as last argument specifies whether screen updates immediately with result. Default is true.
Tip: use a NodeJS image parser to get the pixel data, such as pngparse. A demonstration of using this is below.
Example usage:
`
npm install pngparse
`
`javascript
// Parse the PNG file and draw the bitmap
const image = await new Promise((resolve, reject) => {
pngparse.parseFile('indexed_file.png', (err, image) => {
if (err) reject(err);
else resolve(image);
});
});
await oled.drawBitmap(image.data);
`
This method is provided as a primitive convenience. A better way to display images is to use NodeJS package png-to-lcd instead. It's just as easy to use as drawBitmap, but is compatible with all image depths (lazy is good!). It will also auto-dither if you choose. You should still resize your image to your screen dimensions. This alternative method is covered below:
`
npm install png-to-lcd
`
`javascript
// Convert PNG to LCD bitmap and update the display
const bitmap = await new Promise((resolve, reject) => {
pngtolcd('nyan-cat.png', true, (err, bitmap) => {
if (err) reject(err);
else resolve(bitmap);
});
});
oled.buffer = bitmap;
await oled.update();
`
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Draw an RGBA coded image at specific coordinates. This only supports a monochrome
OLED so transparent pixels must be 100% transparent, off pixels should have an
RGB value of (0, 0, 0), and pixels with any color value will be considered on.
Use a library such as pngjs to read a png
file into the required rgba data structure.
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`javascript
import fs from 'fs';
import { PNG } from 'pngjs';
import i2c from 'i2c-bus';
import Oled from 'oled-i2c-bus';
const setupOled = async () => {
const i2cBus = await i2c.openPromisified(0);
const opts = {
width: 128,
height: 64,
address: 0x3C
};
const display = new Oled(i2cBus, opts);
// Clear the display
await display.clearDisplay();
// Turn on the display
await display.turnOnDisplay();
// Function to draw the image
const drawImage = async (image) => {
const x = Math.floor(Math.random() * (display.WIDTH - image.width / 2));
const y = Math.floor(Math.random() * (display.HEIGHT - image.height / 2));
await display.drawRGBAImage(image, x, y);
};
// Read and draw the PNG image
fs.createReadStream('./test.png')
.pipe(new PNG({ filterType: 4 }))
.on('parsed', async function () {
setInterval(async () => {
await drawImage(this);
}, 1000);
});
};
setupOled();
`
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Scrolls the current display either left or right.
Arguments:
+ string direction - direction of scrolling. 'left' or 'right'
+ int start - starting row of scrolling area
+ int stop - end row of scrolling area
Usage:
`javascript
// args: (direction, start, stop)
await oled.startscroll('left', 0, 15); // this will scroll an entire 128 x 32 screen
`
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Stops all current scrolling behaviour.
Usage:
`javascript
await oled.stopscroll();
`
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Sets the x and y position of 'cursor', when about to write text. This effectively helps tell the display where to start typing when writeString() method is called.
Call setCursor just before writeString().
Usage:
`javascript
// sets cursor to x = 1, y = 1
await oled.setCursor(1, 1);
`
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Writes a string of text to the display.
Call setCursor() just before, if you need to set starting text position.
Arguments:
+ obj font - font object in JSON format (see note below on sourcing a font)
+ int size - font size, as multiplier. Eg. 2 would double size, 3 would triple etc.
+ string text - the actual text you want to show on the display.
+ int color - color of text. Can be specified as either 0 for 'off' or black, and 1 or 255 for 'on' or white.
+ bool wrapping - true applies word wrapping at the screen limit, false for no wrapping. If a long string without spaces is supplied as the text, just letter wrapping will apply instead.
Optional bool as last argument specifies whether screen updates immediately with result. Default is true.
Before all of this text can happen, you need to load a font buffer for use. A good font to start with is NodeJS package oled-font-5x7.
Usage:
`
npm install oled-font-5x7
`
`javascript
import font from 'oled-font-5x7';
// sets cursor to x = 1, y = 1
await oled.setCursor(1, 1);
await oled.writeString(font, 1, 'Cats and dogs are really cool animals, you know.', 1, true);
`
Checkout https://www.npmjs.com/package/oled-font-pack for all-in-one font package.
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Sends the entire buffer in its current state to the oled display, effectively syncing the two. This method generally does not need to be called, unless you're messing around with the framebuffer manually before you're ready to sync with the display. It's also needed if you're choosing not to draw on the screen immediately with the built in methods.
Usage:
`javascript
await oled.update();
`
$3
Draw a battery level in percentage indicator. This method allows for up to 4 different states of the battery:
- 0 bar : battery < 10%
- 1 bar : 10% >= battery < 40%
- 2 bar : 40% >= battery < 70%
- 3 bar : battery >= 70%
Arguments:
* int x - start column
* int y - start row
* int percentage - battery level percentage
usage:
`javascript
// args: (x,y,percentage)
await oled.battery(1,1,20);
`
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Draw a bluetooth icon
usage:
`javascript
//args: (x,y)
await oled.bluetooth(1,1);
`
$3
Draw a WiFi signal strength in percentage indicator. This method allows for up to 4 different signal strength of the WiFi signal:
- 0 bar : signal < 10%
- 1 bar : 10% >= signal < 40%
- 2 bar : 40% >= signal < 70%
- 3 bar : signal >= 70%
Arguments:
* int x - start column
* int y - start row
* int percentage - signal strength in percentage
usage:
`javascript
// args: (x,y,percentage)
await oled.wifi(1,1,20);
`
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A wrapper for drawRGBAImage that supports a fix animation. The animation always start from x=1 and y=1.
Arguments:
* int x - start column (ignored on animation = true)
* int y - start row (ignored on animation=true)
* string image - full path to the image or the filename of the image in the resources folder
* object font - font to draw "error" message
* boolean clear - clear the display before the draw
* boolean reset - stop all animations
* boolean animated - enable/disable animation
* boolean wrapping - enable/disable of the error message wrapping
usage:
`javascript
import font from 'oled-font-5x7';
await oled.image(1,1,'rpi-frambuesa.png',font.oled_5x7,true,false,false,true);
``