search

RobTillaart / HT16K33

Arduino Library for HT16K33 4x7segment display
MIT License
24 stars 6 forks source link

1.2" 7-segment display doesn't display numbers #2

Closed raccettura closed 4 years ago

raccettura commented 4 years ago

I tested this library out this afternoon with limited success using PlatformIO and an ESP32 and a 1.2" 7 segment LED panel with a HT16K33 backpack.

displayTest() causes the dots on the display to flash. However none of the tests manage to illuminate any of the seven segments. Any thoughts as to why this would be? My assumption would be the 0.56" and 1.2" would be nearly identical in behavior.

RobTillaart commented 4 years ago

Hi, I have done tests with ESP and had it work, so lets think what could be the cause.

The dots are flashing so there is some sort of communication, so we can assume the pins are correct.

operating voltage The OV of the HT16K33 is 4.5 - 5.5 V and the ESP is typical 3.3V, so connect the VCC to the 5V of the ESP. If you already did that you might consider testing it with an external 5V power supply. As the 1.2" version is larger I assume it needs up to 4x more power than the 0.56" as size works in 2 dimensions. Protocol / signal wise I expect they are identical.

From https://learn.adafruit.com/adafruit-led-backpack/1-2-inch-7-segment-backpack-arduino-wiring-and-setup image

Pull up resistors The SDA and SCL lines of the I2C need a pull-up resistor, and depending on the length of the wires that should be a smaller one. indicative 0-25 cm => 4K7 25 - 75 cm 3K3 75-150 cm 2K2 and beyond 1K

long wires For long wires should be twisted. This reduces he interference from outside signals

Hope these steps helps you to get it working, otherwise let me know.

raccettura commented 4 years ago

So took some tinkering but I got it working tonight. Looks like the larger version works just fine with 5V, however not every USB port has enough current.

Thanks for the feedback. This is a much lighter approach to controlling this display over the more bloated options out there.

RobTillaart commented 4 years ago

Thanks for the update, good to hear you are satidfied. If you miss functionality in the library (or any of my other libs), please let me know.

BTW, Did you find information or did you measure how much current it actually draws? This would be interesting information for the readme.md file.

Thanks, Rob

raccettura commented 4 years ago

Unfortunately I did not, but I've also got a few other sensors attached, so that might have also contributed now that I think about it.

RobTillaart commented 4 years ago

Ok extra sensors add up in power. For the display you could consider using less brightness, although I don't know if that would reduce power consumption.

Update This faq has some indication https://learn.adafruit.com/adafruit-led-backpack/faq Up to 160 mA max which is substantial.