# Bi-Color (Red/Green) 24-Bar Bargraph w/I2C Backpack Kit

**Type:** Product page · **SKU:** ADA1721 · **Brand:** [Adafruit](https://core-electronics.com.au/brands/adafruit-australia)
**Page:** https://core-electronics.com.au/bi-color-red-green-24-bar-bargraph-w-i2c-backpack-kit.html ([markdown](https://core-electronics.com.au/bi-color-red-green-24-bar-bargraph-w-i2c-backpack-kit.html.md))

What's better than a single LED? Lots of LEDs! A fun way to make a small linear display is to use two 12-bar Bi-color bar-graphs. However, this LED bargraph is 'multiplexed'...

## Pricing

- **Price:** $18.95 (inc GST) — $17.23 AUD, exc GST
- **Quantity discounts:** 10+ $16.71 (exc GST) · 50+ $16.36 (exc GST)

## Availability & dispatch

- Available with a lead time — expect dispatch between Aug 21 and Aug 25.

## Description

What's better than a single LED? Lots of LEDs! A fun way to make a small linear display is to use two 12-bar Bi-color bar-graphs. However, this LED bargraph is 'multiplexed' - so to control all the 48 LEDs you need a lot of pins. [There are driver chips like the MAX7219](https://core-electronics.com.au/max7219cng-led-matrix-digit-display-driver-max7219.html) that can help control a bar-graph/matrix for you but there's a lot of wiring to set up and they take up a ton of space. Here at Adafruit Adafruit feel your pain! After all, wouldn't it be awesome if you could control a colorful bargraph without tons of wiring? That's where this adorable LED bar-graph backpack comes in. Much like Adafruit's 8x8 and 7-segment backpacks, this backpack pairs perfectly with Adafruit's bar-graphs and manages all the LED control and multiplexing.

The backpack uses a driver chip that does all the heavy lifting for you: It has a built in clock so it can multiplex the display. It uses constant-current drivers for ultra-bright, consistent color, 1/16 step display dimming, all via a simple I2C interface. The backpack comes with address-selection jumpers so you can connect up to eight of these bar-graphs on a single I2C bus. You can also mix-and-match the bar-graph breakout with Adafruit's other types of I2C LED backpacks.

The product kit comes with:

- A fully tested and assembled LED backpack stick
- [Two 12-bar bi-color bar-graphs](https://core-electronics.com.au/bi-color-red-green-12-led-bargraph-pack-of-2.html)
- 4-pin header
 
A bit of soldering is required to attach the matrix onto the backpack but its very easy to do and only takes about 5 minutes.

Of course, in classic Adafruit fashion, We also have a detailed tutorial showing you how to solder, wire and control the display. They even wrote [a very nice library for the backpacks so you can get running in under half an hour, displaying images on the matrix or numbers on the 7-segment](https://github.com/adafruit/Adafruit-LED-Backpack-Library). If you've been eyeing matrix displays but hesitated because of the complexity, his is the solution you've been looking for!

Bi-Color (Red/Green) 24-Bar Bargraph w/I2C Backpack Kit (4:37)

## Technical Details

- Bargraph Dimensions: 10mm x 30mm ( 0.4" x 1.2")
- 7mm (0.3") thick
- [Lots more LED details including dimensions, pinouts, etc in the datasheet, this is the Common-Cathode model KWL-R1230CDUGB](https://core-electronics.com.au/attachments/localcontent/KWL-R1230XDUGB_12607d54ef7.pdf)
- Board Dimensions: 13mm x 101mm (.5" x 4")
- Chipset: HT16K33
 
[Datasheets, schematic, EagleCAD PCB files, and Fritzing available in the product tutorial](https://learn.adafruit.com/adafruit-led-backpack/downloads)

 ![](https://core-electronics.com.au/attachments/localcontent/rohs_icon_8216055e11.jpg)

## Images

- [Product image 1](https://core-electronics.com.au/media/catalog/product/1/7/1721-00.jpg)