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Hi-Tech / Hardware

Display two-colour seven-segment display 1.8" 12.02.2020 at 06:00

As one friend asked me to collect the clock sync from the Internet is a large seven-segment indicator. With the project coped without problems, but the wife of a friend very quickly put him on the cross — "I Want the same but without wings, the Red numbers don't like — I want green." At that time color indicators cost several times more expensive than red (and now the trend continues) and the watch left somewhere to gather dust with the women's sight. And then one day, creating order on TaoBao, I came across two-color indicators. Thought, with whatever pride I'd satisfy the desire of women, with the phone by changing the color of the numbers of hours and decided to order.

With the order received cant. Wanted to order the indicators with common cathode to normally connect via MAX7219. But one seller of the indicators was not available, and ordering the other did not understand Chinese-English translation on the website of the intermediary "Common Yang/ Yin Common" (Yes, Yes, total Yin or total Yang) and ordered a common anode. Fortunately, working with the MAX7219 and LED matrix 8×8, and I decided to change the diagram and solve the problem at the software level.

the Entire Datasheet to the indicators fit on one picture. Thank you for that.

the Scheme made up so that segments connected to the pins of the digits to the MAX7219, and the red and green anodes 4 LEDs to the pins of the segments.

MAX7219 took the case SOP24

the Circuit and PCB was designed in DipTrace. The third indicator is turned 180 degrees to make a colon to separate hours and minutes when displaying time.

patient and waiting for the LEDs and circuit Board

soldering is no big deal. Although the legs of the indicators could be smaller )))

the Size turned out 153x56x15

Weight 130 g

To connect take popular the LedControl library and extend its work with display

the Results of one character is performed by the method setColumn(), which room drains 0-7 this category and color.

Changed the library, I called LedControlDC. You can download it from GITHUB.

Put several examples of two-color display

the Video, all the examples

the First example made specially for the measurement of consumption indicators. Operating voltage range of 4 — 6V. Less than four volts does not burn practically green LEDs included two in series in each segment. 6V is the maximum voltage the chip MAX7219

the Green color looks good from 5V

Schedule of capacity for each color depending on the supply voltage. At 6V the maximum intake of each colour of about 1W, the total of two colors — 1.7 W (adjustable MAX7219)

needless to say, the indicators are very interesting and will take a worthy place in my homemade

Now I can't wait when I get the ordered boards for ESP8266 controller on which you plan to implement a clock. But alas, new year and coronavirus spawned off season in the trade with China

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