Hardware
There are many ways to build this scoreboard and here I'll post the different setups the community tested and the we know work.
What you need is basically.
- A raspberry pi (Zero WH, 3B+, 3A+, 4B)
- A Class 10 micro sd card (8GB or more)
- A 64x32 LED matrix board (See below to choose the right one for you)
- Either the Adafruit RGB Matrix HAT or the Adafruit RGB Matrix Bonnet.
- A 5V 4A (4000 mA) Power supply. 4A is the minimum you will need, but I strongly suggest at least 8 or 10A. More details below.
- A precision screwdriver kit (like this one)
Matrix board comes in different size and they are defined by the spacing between each LED. So when you see a 64x32 P3 LED matrix, this means there is 3mm separating each LED. This is really important because the closer the LED are from each other the harder it is to read from a distance.
- P3: Optimal distance is about 2 meters (6.5 feet). Perfect for desktop and small room.
- P4: Great for any indoor situation. It might be a bit too large for desktop.
- P5: Perfect for Garage and workshops. Great for indoor and outdoor.
- P6: Optimal for outdoor, like displayed from a window or on a balcony.
If you are new to the world of electronics, I strongly recommend ordering your matrix from a reputable seller like Adafruit and Sparkfun. They are more expensive, but you are sure to have a matrix that was tested and will work.
Of course, you can buy these kinds of matrix a bit everywhere now. Aliexpress is filled with options but not all work with the Adafruit HAT/Bonnet or the rgb-led-matrix repository.
The specs to look for are:
- Type of connector needs to be a HUB75
- Scan rate of 1:16
- Pixel configuration 1R 1G 1B
Even with these specs, there is a chance that the matrix board won't work for all sorts of reasons. If you order from these shops and have trouble running your board, look at the issues on the rgb-led-matrix repo and you might find a solution there.
If you don't own a soldering iron, pick up the bonnet. All Raspberry Pi models except come with a pre-soldered header except for the raspberry pi zero, which you have to specifically buy the pre-soldered version. Make sure that you order the right one.
A single 32x16 or 32x32 RGB matrix, running full tilt (all pixels set white), can require nearly 4 Amps of current! Double that figure for a 64x32 matrix. -From Adafruit 32x12 and 32x32 matrix guide.
So running a single 64x32 led matrix can pull up to 8A if all the led's brightness are set to 100% and the color is set to white. Keep that in mind if you play around with the rgb-led-matrix repo.
If you use a 4A power supply with this project, you should be fine as long as you keep the brightness under 60%.
Find here the Power Consumption Benchmarks. As you can see in the benchmarks, each Pi models have different power consumption. Also Note that these benchmarks show an average power consumption. Computers and electronics have peaks in their consumption which means if you drive a Pi 3B+ without anything plugged to it (no usb and no HDMI) for exemple, it will hover around 980mA but it might peak over 1000mA for fraction of seconds and that can corrupt your SD card if the power supply don't provide enough juice.
We recommend powering your driving Raspberry Pi from the Pi's microUSB port but we do have a 1A diode on board that will automatically power the Pi if/when the voltage drops. So if you want, just plug in the 5V wall adapter into the HAT and it will automagically power up the Pi too!
As you can see, there is a way to power the Pi through the HAT (same for the Bonnet) as long as the Pi don't need more than 1A (1000mA). So if you have a Pi 3B+ and run raspbian buster lite, and don't have anything plugged in the USB ports or on the GPIO pins other then the HAT and Bonnet, your setup can run easily with the power provided by the HAT/Bonnet. I've been running this exact setup for a year now without any issue.
That's not the case for the Raspberry pi 4B. We strongly recommend to power this model with it's own PSU, otherwise you are risking corrupting the SD card and need to reinstall everything.