**Creating a 4-Digit Display with Discrete Logic**

Are you familiar with common cathode displays? If so, you know that to control all individual cathodes of our display, we need an active high level. The datasheet tells us where to connect 5 volts and ground, and also how to hook up our bars.

For a common cathode display, you would need an active high level. The datasheet tells us where to connect 5 volts and ground, and also how to hook up our bars. A 2 G to the I see is used, with 220 ohm resistors to connect the bars to the IC to limit the current.

If we connect the lamp test pin to ground, all balls should light up, and we know everything works now. We can then connect lamp tests to 5 volts, and feed the IC four inputs which are ABCD to let it know which number to display.

We can look at the function list and find out which combination of ABCD outputs which number, for example, a low B and C high and D low represents number six. Wait, it works but how to control those four inputs without an Arduino? About a 4-bit binary counter, the SN7-5090 why this counter well, it has a BCD count sequence so these two are pretty easy to combine.

An active high level is needed for a common cathode display. The datasheet tells us where to connect 5 volts and ground, and also how to hook up our bars. A 2 G to the I see is used with 220 ohm resistors to connect the bars to the IC to limit the current.

If we connect the lamp test pin to ground, all balls should light up and we know everything works now. We can then connect lamp tests to 5 volts and feed the IC four inputs which are ABCD to let it know which number to display.

We can look at the function list and find out which combination of ABCD outputs which number for example a low B and C high and D low represents number six. Wait, it works but how to control those four inputs without an Arduino?

About a 4-bit binary counter, the SN7-5090 why this counter well it has a BCD count sequence so these two are pretty easy to combine as always i hook up five volts to VCC ground to ground QA to input a QB to be Q C to C and Q D to D. I also connect QA 2 o'clock three to activate the BCD count and we need to connect ground to pin 13 and 3 to activate the count sequence.

Whenever we connect clock A to ground, the counter goes one up and we see the next number. You can for example hook up a push-button at clock A and press it whenever someone annoys you during work this way you have a homemade rage meter or you hook up other sensors like a tilt switch or infrared sensor there are tons of things to count it is a great project for people who don't like programming.

To keep track of time, these displays have 16 LEDs in sides and two common anodes to activate either the left or the right digit. We cannot control all 42 LEDs of those two displays with one IC we know if you watch my videos often you may already know the solution for the problem multiplexing this way.

We would only need 12 pins, 8 for the cathode voltages of all bars and 4 for the common anodes but that means we already use a lot of the Arduino power just for the display. How about using another IC which is especially designed to handle this display? The SI-A1064 can do this one of those can control four digits by multiplexing two digits at a time and you can connect them together which means sixteen digits maximum.

It uses the I2C communication protocol which is supported by the Arduino. For more detailed handwritten tutorial about I2C and this IC, I would suggest tronic staffs tutorial it's awesome but let's just build the circuit for now here is my schematic. We connect pin 1 directly to ground to set the I2C address to 0X70.

I use a 2.2 nano farad capacitor on pin 10 to 20 to set the speed for the multiplexing and I connect a 4.7 kilo ohm resistor between pin 23 and 5 volts and pin 24 on 5 volts as pull-up resistors. Pin 23 then connects to a 4 on the Arduino and pin 24 to a GND.

The rest wiring is well described in the schematic when the circuit is done we need code and code for I2C is a bit more advanced so let's use a cool SA-A1064 library.

WEBVTTKind: captionsLanguage: ensome time ago I was asked to make a video about a 7 segment Audrey no clock and I thought cool sounds nice now everybody knows what an Arduino is but those seven segment displays are kind of old-school are not often used in modern consumer electronics but they are very useful if you want to build a small project which only outputs a couple of numbers or letters like a clock a temperature sensor or the voltage and current of a power supply so today I will show you how to use those displays with and without an Arduino microcontroller firstly let's take a look at different species of this display there is a really simple one with only one digit in a case and the more common two digits in one case and whatever kind of display you gets always check the datasheet to find the pin out in my case I have a LTS five four six a gene what we learn from the datasheet you may ask first of all we see that we are basically working with eight individual LEDs seven forty bars and one for the decimal point these LEDs are connected in a common anode configuration so we have one common plus terminal for all LEDs which are the pins three or eight doesn't matter which one I use both do the same and here you can also see the pin labeling for the display just by the way now we want to control the bars and the dots we check the datasheet and see that the bars are label from A to G and the dot is DP we scroll down a bit and there it is now we know which pin is which are and we can use this display to our heart's desire just be sure to use two point one volts and not five volts but stay tuned full of destruction at the end of the video but how can we display numbers without a microcontroller the easy solution is a BCD to seven-segment display driver I'm using a SN 7 for LS 2 4 7 which has an active low level which means it is capable of controlling all individual cathodes of our display if you would use a common cathode display you would need an active high level the datasheet tells us where to connect 5 volts and ground and also how to hook up our bars a 2 G to the I see I'm using 220 ohm resistors to connect the bars to the IC to limit the current if I connect the lamp test pin to ground all ball should light up and we know everything works now we connect lamp tests to 5 volts and we have to feed the IC 4 inputs which are ABCD to let it now which number should light up we can look at the function list find out which combination of ABCD outputs which number for example a low B and C high and D low represents number six wait it works but how to control those four inputs without an Arduino how about a 4-bit binary counter the sn7 for two nine zero why this counter well it has a BCD count sequence so these two are pretty easy to combine as always i hook up five volts to VCC ground to ground QA to input a QB to be Q C to C and Q D to D I also connect QA 2 o'clock thee to activate the BCD count and we need to connect ground to pin 13 and 3 to activate the count sequence now whenever we connect clock a to ground the counter goes one up and we see the next number you can for example hook up a push-button at clock a and press it whenever someone annoys you during work this way you have a homemade rage meter or you hook up other sensors like a tilt switch or infrared sensor there are tons of things to count it is a great project for people who don't like Audrey know and want to start with discrete logic but for most projects you need more than one digit I would recommend for to keep track of time for example these displays have 16 LEDs in sides and two common anodes to activate either the left or the right digit of course we cannot control all 42 LEDs of those two displays with OneNote we know if you watch my videos often you may already know the solution for the problem multiplexing this way we would only need 12 pins 8 for the cap votes of all bars and 4 for the common anodes but that means we already use a lot of the Arduino power just for the display how about using another IC which is especially designed to handle this display the SI a one zero six four can do this one of those can control four digits by multiplexing two digits at a time and you can connect for those together which means sixteen digits maximum it uses the I square C communication protocol which is supported by the Arduino on extra detailed handwritten tutorial about I square C and this IC I would suggest tronic staffs tutorial it's awesome but let's just build the circuit for now here is my schematic we connect pin 1 directly to ground to set the I square C address to 0 X 7 0 I use a 2.2 nano farad capacitor on pin to to set the speed for the multiplexing and I connect a 4.7 kilo ohm resistor between pin 23 and 5 volts and pin 24 on 5 volts as pull-up resistors pin 23 then connects to a 4 on the Arduino and pin 24 to a 5 and we need two basic NPN transistors to multiplex here I'm using the BC 3 3 7 which works just fine the rest wiring is well described in the schematic when the circuit is done we need code and code for I square C is a bit more advanced so let's use a cool sa a 1 0 6 4 library if I upload the example code you can see that all digits do the right thing now I can display all kinds of things pretty easily on my display without using too much processing power of the Arduino as always feel free to experiment with the library and the IC I hope you learned something today with this video as always you would do me a huge favor if you would give me a like don't forget to subscribe and spread the word that there is a crazy guy in the computer screen trying to entertain you stay creative and I will see you next timesome time ago I was asked to make a video about a 7 segment Audrey no clock and I thought cool sounds nice now everybody knows what an Arduino is but those seven segment displays are kind of old-school are not often used in modern consumer electronics but they are very useful if you want to build a small project which only outputs a couple of numbers or letters like a clock a temperature sensor or the voltage and current of a power supply so today I will show you how to use those displays with and without an Arduino microcontroller firstly let's take a look at different species of this display there is a really simple one with only one digit in a case and the more common two digits in one case and whatever kind of display you gets always check the datasheet to find the pin out in my case I have a LTS five four six a gene what we learn from the datasheet you may ask first of all we see that we are basically working with eight individual LEDs seven forty bars and one for the decimal point these LEDs are connected in a common anode configuration so we have one common plus terminal for all LEDs which are the pins three or eight doesn't matter which one I use both do the same and here you can also see the pin labeling for the display just by the way now we want to control the bars and the dots we check the datasheet and see that the bars are label from A to G and the dot is DP we scroll down a bit and there it is now we know which pin is which are and we can use this display to our heart's desire just be sure to use two point one volts and not five volts but stay tuned full of destruction at the end of the video but how can we display numbers without a microcontroller the easy solution is a BCD to seven-segment display driver I'm using a SN 7 for LS 2 4 7 which has an active low level which means it is capable of controlling all individual cathodes of our display if you would use a common cathode display you would need an active high level the datasheet tells us where to connect 5 volts and ground and also how to hook up our bars a 2 G to the I see I'm using 220 ohm resistors to connect the bars to the IC to limit the current if I connect the lamp test pin to ground all ball should light up and we know everything works now we connect lamp tests to 5 volts and we have to feed the IC 4 inputs which are ABCD to let it now which number should light up we can look at the function list find out which combination of ABCD outputs which number for example a low B and C high and D low represents number six wait it works but how to control those four inputs without an Arduino how about a 4-bit binary counter the sn7 for two nine zero why this counter well it has a BCD count sequence so these two are pretty easy to combine as always i hook up five volts to VCC ground to ground QA to input a QB to be Q C to C and Q D to D I also connect QA 2 o'clock thee to activate the BCD count and we need to connect ground to pin 13 and 3 to activate the count sequence now whenever we connect clock a to ground the counter goes one up and we see the next number you can for example hook up a push-button at clock a and press it whenever someone annoys you during work this way you have a homemade rage meter or you hook up other sensors like a tilt switch or infrared sensor there are tons of things to count it is a great project for people who don't like Audrey know and want to start with discrete logic but for most projects you need more than one digit I would recommend for to keep track of time for example these displays have 16 LEDs in sides and two common anodes to activate either the left or the right digit of course we cannot control all 42 LEDs of those two displays with OneNote we know if you watch my videos often you may already know the solution for the problem multiplexing this way we would only need 12 pins 8 for the cap votes of all bars and 4 for the common anodes but that means we already use a lot of the Arduino power just for the display how about using another IC which is especially designed to handle this display the SI a one zero six four can do this one of those can control four digits by multiplexing two digits at a time and you can connect for those together which means sixteen digits maximum it uses the I square C communication protocol which is supported by the Arduino on extra detailed handwritten tutorial about I square C and this IC I would suggest tronic staffs tutorial it's awesome but let's just build the circuit for now here is my schematic we connect pin 1 directly to ground to set the I square C address to 0 X 7 0 I use a 2.2 nano farad capacitor on pin to to set the speed for the multiplexing and I connect a 4.7 kilo ohm resistor between pin 23 and 5 volts and pin 24 on 5 volts as pull-up resistors pin 23 then connects to a 4 on the Arduino and pin 24 to a 5 and we need two basic NPN transistors to multiplex here I'm using the BC 3 3 7 which works just fine the rest wiring is well described in the schematic when the circuit is done we need code and code for I square C is a bit more advanced so let's use a cool sa a 1 0 6 4 library if I upload the example code you can see that all digits do the right thing now I can display all kinds of things pretty easily on my display without using too much processing power of the Arduino as always feel free to experiment with the library and the IC I hope you learned something today with this video as always you would do me a huge favor if you would give me a like don't forget to subscribe and spread the word that there is a crazy guy in the computer screen trying to entertain you stay creative and I will see you next time