11/24/2023 0 Comments Arduino led matrix max7219![]() If you have more than one MAX7219, connect the DOUT (“data out”) pin of the first MAX7219 to pin 1 of the second, and so on. the digital pin connected to pin 12 of the MAX7219 (“LOAD”).the digital pin connected to pin 13 of the MAX7219 (“CLK or clock”).the digital pin connected to pin 1 of the MAX7219 (“data in”).The first pulls in the library, and the second line sets up an instance to control. You need the following two lines at the beginning of the sketch: #include "LedControl.h" These are great for experimenting with and can save you a lot of work – some examples of which are shown below: In the last few months there has been a proliferation of inexpensive kits that contain a MAX7219 or equivalent, and an LED matrix. We’ll get to that in the moment, but before that let’s return to the matrix modules. Finally, the MAX7219 serial in, load and clock pins will go to Arduino digital pins which are specified in the sketch. if you have a 2V 20 mA LED, your resistor value will be 28kΩ (the values are in kΩ). You’ll need to know the voltage and forward current for your LED matrix or numeric display, then match the value on the table. Have a look at table eleven on page eleven of the data sheet: ![]() The MAX7219 is a constant-current LED driver, and the value of the resistor is used to set the current flow to the LEDs. The circuit is quite straight forward, except we have a resistor between 5V and MAX7219 pin 18. A total example circuit with the above matrix is as follows: Wiring up a matrix is very simple – if you have a common matrix with the following schematic:Ĭonnect the MAX7219 pins labelled DP, A~F to the row pins respectively, and the MAX7219 pins labelled DIG0~7 to the column pins respectively. The MAX7219 drives eight LEDs at a time, and by rapidly switching banks of eight your eyes don’t see the changes. Here is the pinout diagram for the MAX7219: And another good thing – when powered up, it keeps the LEDs off, so no wacky displays for the first seconds of operation. For more technical information, here is the data sheet: MAX7219.pdf. Now to put it to work for us – we’ll demonstrate using one or more 8 x 8 LED matrix displays, as well as 8 digits of 7-segment LED numbers.īefore continuing, download and install the LedControl Arduino library as it is essential for using the MAX7219.Ĭontrolling LED matrix displays with the MAX7219įirst of all, let’s examine the hardware side of things. You can even switch the display off for power saving mode, and still send it data while it is off. It can refresh the LEDs at around 800 Hz, so no more flickering, uneven LED displays. As mentioned earlier, the MAX7219 can completely control 64 individual LEDs – including maintaining equal brightness, and allowing you to adjust the brightness of the LEDs either with hardware or software (or both). ![]() You might not see the AS1107 around much, but it can be cheaper – so don’t be afraid to use that instead:Īt first glance you may think that it takes a lot of real estate, but it saves some as well. Here’s an example of a MAX7219 and another IC which is a functional equivalent, the AS1107 from Austria Microsystems. Overall – they’re a lot of fun and can also be quite useful, so let’s get started. Furthermore they can be chained together to control two or more units for even more LEDs. And for good reason, it’s a simple and somewhat inexpensive method of controlling 64 LEDs in either matrix or numeric display form. ![]() Sooner or later Arduino enthusiasts and beginners alike will come across the MAX7219 IC.
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