Description
What's better than a single LED? Lots of LEDs! A fun way to make a numeric display is to use a 4-digit 7-segment display. LED matrices like these are 'multiplexed' - so to control all the seven-segment LEDs you need 14 pins. That's a lot of pins, and there are driver chips like the MAX7219 that can control a matrix for you but there's a lot of wiring to set up and they take up a ton of space. Here at Adafruit we feel your pain! After all, wouldn't it be awesome if you could control a matrix without tons of wiring? That's where these adorable LED matrix backpacks come in. We have them for a variety of 8x8 and 7-segment displays. They work perfectly with the displays we stock in the Adafruit shop and make adding a bright display trivial.
The backpacks use a driver chip that does all the heavy lifting for you: They have a built in clock so they multiplex the display. They use constant-current drivers for ultra-bright, consistent color (the images above are photographed at the dimmest setting to avoid overloading our camera!), 1/16 step display dimming, all via a simple I2C interface. The backpacks come with address-selection jumpers so you can connect up to eight 7-segments (or a combination, such as four mini 8x8's and four 7-segments, etc) on a single I2C bus.
Since this display has two LEDs per segment in series we need to power from 5V, even when using 3V logic. However, the chip really prefers the IO signals to be close to the power voltage. Our new version of the backpack now has level shifters and a small boosting converter, so you can use 3.3V or 5.0 power and data and still get the nice bright LEDs.
The product kit comes with:
- A fully tested and assembled LED backpack
- Ultra-bright 4-digit 1.2" tall yellow seven-segment display
- 5-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. We even wrote very nice libraries for the backpacks so you can get running in under half an hour, displaying numbers on the 7-segment for either Arduino or Raspberry Pi. If you've been eyeing matrix displays but hesitated because of the complexity, his is the solution you've been looking for!
Revision History:
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As of June 30, 2023 - this kit has revised the 7 segment backpack. It now has a 5V boost converter plus stemma QT ports. We've also updated this PCB with Adafruit Pinguin to make a lovely and legible silkscreen.
Technical Details
- 50mm/2" wide
- 120mm/4.7" long
- 13mm/0.5" high
- This board/chip uses I2C 7-bit addresses between 0x70-0x77, selectable with jumpers.
Resources
Refund Policy
Our policy lasts 7 days. If 7 days have gone by since your purchase, unfortunately we can’t offer you a refund or exchange.
To be eligible for a return, your item must be unused and in the same condition that you received it. It must also be in the original packaging.
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Sale items (if applicable)
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Exchanges (if applicable)
We only replace items if they are defective or damaged. If you need to exchange it for the same item, send us an email at ecorobotics@ecoprojects.com.na and send your item to: Ecoprojects CC, Maxwell Street, Nr 1 Maxwell Park, 10023 Windhoek, Namibia.
Gifts
If the item was marked as a gift when purchased and shipped directly to you, you’ll receive a gift credit for the value of your return. Once the returned item is received, a gift certificate will be mailed to you.
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To return your product, you should mail your product to: Ecoprojects CC, Maxwell Street, Nr 1 Maxwell Park, 10023, Windhoek, Namibia
You will be responsible for paying for your own shipping costs for returning your item. Shipping costs are non-refundable. If you receive a refund, the cost of return shipping will be deducted from your refund.
Depending on where you live, the time it may take for your exchanged product to reach you, may vary.
If you are shipping a high-cost item, you should consider using a trackable shipping service or purchasing shipping insurance. We don’t guarantee that we will receive your returned item.