This is the first video I completely understood about the work of a display. Other people just use libraries without explanation lol. Using multiple displays without increasing number of pins is amazing.
Check my other tutorials like 7219 which can be a good alternative to using shift registers . I will be releasing hopefully within 2 weeks video where I build custom 3dprinted 7segments display clock using max7229 chip
Back in the early '90, I used 4 CD4094 shift registers (similar to 74hc595) and used the clock pin to discharge a capacitor (to Gnd) resistor (to 5V) through a diode to automatically strobe the data. Only 2 pins used. It was controlled via the parallel port of a Dragon 32. Great times
I have to admit I am not familiar with CD4094. Does it work in more or less the same way as 74hc595 or the concept is different. The use of the two pins with use of capacitor sounds like something that is waaay over my head:) Can you explain the concept?
@@marios_ideas Yes, cd4094 and 74hc595 are the same except pinout. A resistor connected to 5V charges a capacitor and the diode connected to the clock discharges it. At the end of the transmission, clock stays high, the capacitor charges and triggers the strobe.
Hello Mario, I just want to convey my appreciation , i.e. on how to wire and program four (4) common cathode 7-segment displays (2.3"). I followed your advice (reversed the polarity and make the 0s to 1s on the code). It works very well ! I'd like to upload a short video clip, but I'm not sure if its allowed in the comments. Anyway, you are a great teacher and again, many thanks for the prompt response and advice. You made my day!
Hello. Very nice video explaining shift registers, especially the part where you explain the data sent over the different channels. Nice would be though to also include to dot as the 8th out pin instead of leaving it unused .
I know this video is geared for Arduino board users, I was hoping that there wouldn't be much difference for ESP32 boards. I don't know if ESP32 boards accept/understand the first format, but I found some examples using the shiftOut method, and the ESP32 board ran it successfully. You explained this complicated stuff well!
Glad you liked it. I am not an expert. I stumbled upon Arduino 2 years ago and it became my hobby. I learn as I go alone. And as I learned I struggled to find one comprehensive guide for each topic I was interested in. So I decided to create such tutorials myself:)
@@marios_ideas I understand! When you can finally figure out something that's complicated, you make the best to teach it to others. I got my starter kit about 2.5 years ago, picked it up but let it sit on my shelf for a year or so because it was getting complicated. I treat it like a hobby instead of a job now. It should be enjoyable, and if a component becomes too challenging, I switch to some other Arduino component. Now, I want to move on to the 4 digit 7 segment display.
Thanks. If you are interested in shift registers please also check ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-sQfghvHYTlk.html . It covers different type but it also revisits 595 as well.
What about driving multiple seven segment displays with just two wires (data wire and ground) from the MCU?.using for example NRZ , Manchester coding or other asynchronous serial data transfer schemes ,is it possible?
Hello Mario, By watching this video, I understood how 74HC595 works. I can adjust the outputs of 3 ICs. Thank you!. Currently, I need to read the logic values of the outputs using the Data_out pin. How can I do this using GPIO pins?
I want to add a third digit to display a 3 digit count with a maximum of 999 - full three digits. Can I modify your code by adding a "third" for loop - for (int k=0; k
Thank you for the video and I have a question. I'm wondering if I could use 4 digit 7 segment display with two of these shift registers and Arduino and then also connect something else to it? I mean if the Arduino wouldn't blow up or something.
Arduino would not blw up. If you cnnect more sensors potentially you may need power e.g. shift registers from external 5v power source as Arduino may not cope with too many devices. Then data pis of shift registers, servos , led strips etc stil go to arduino but you connect 5x and GND to external power source
I think you may be overdriving the 74HC595 which has a total chip current limit of 70mA. What value did you use for your current limiting resistors (you appear to be inconsistent across the two displays),
This is an old video an i am fully aware of my electronic shortcomings. i will check but i think i was using 220ohm resistors but the couple of 330ohm could have sneeked as well. Can you let me know How you would do it not to overdrive the shift register. What is going to happen when it overdrives, will it be damaged or will it work in unpredictable way
@@marios_ideas Powering at 5v, assuming 2v forward voltage typical for each red LED, and 220 ohm resistor, each LED consumes (5-2)/220 = 13.6mA. When all 7 segments are lit producing an "8", that's 7*13.6mA = 95mA. The datasheet for the 74HC595 specifies a max chip current of 70mA (note: one should always go under that amount, leaving some headroom). I see many videos which makes this same mistake, one should always read the datasheet and understand the limitation of the devices, I can't stress that enough. A simple fix would be to use a higher resistor value. 470 ohm would be fine and I doubt that you'd even notice a difference in brightness (due to the V I curve of LEDs). the 74HC595 is not designed to be an LED driver. If you really needed to drive more current, then its common to use a TPIC6595 or pair the 595 with ULNs which are darlington sink drivers and can handle a much larger current draw. Also, if you overdrive it, 1 - you might get "lucky" and nothing may happen, 1- the chip might overheat, 3 - the chip may behave unpredictably, 4 - the chip may not last very long. Also, you should use a decoupling capacitor on each 74HC595 since they are prone to spikes due to their switching speed. Thanks for responding, we are all here to learn.
Thank. That was valuable lessin. I think i had some unpredictable behaviour in one of my projects which i did not understand. As to capacitor which should be a value and where should i place it, between vcc and gnid pins of register?
Since we are talking I would ask you to have a look at my other shift register video. There I was testing a breakout board for 74HC164. There I went for a shortcut and used just one current limiting resistor connected to common pin. I know this is not the right way to do but am I right in saying that this way I will not overdrive the shift register. When purchasing this from china I did not receive a datasheet for this part. Should I then in this case check generla datasheet for 74HC164 chip?
"Bits are shifted into the shift register when the clock pin transitions from high to low." ~checks datasheet~ Other way around, m8. You had my attention there for a sec. I was getting a weird bug last night that would have been explained by that.
I know it's low to high. I checked the datasheet. I'm not sure why another video needs to be involved here. Your video said "high to low". Hence the quotation marks.
Hi Mario. I really appreciate your work! Your videos are great helping me to get along with Arduino and getting inspiration for new projects. For comprehension I have one question: How do you ensure that 8-bits will be transferred to the shift register (for example - sending int 0 to print the digital "8"). If I am correct the data type int can range from 8-bit to higher...how do we make clear that we send 7 zeros after a high to print an "0" as another example. Have a good day!
Well I am not sending intiger value to the register. I am sending it to my custom function which in turn pushes 8 bits one by one to a register , 8 bits that correspond to the digit that was received by the function. The graphical representation of sending of those bits for digit 4 is shown at time 3:47 And the function that dooes it is display digit that can be seen at 6:11
You have to figure it out for yourself. I have a video about building a timer. We can get some ideas from it. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-9a5q-xDvZQs.html
The type of Seven Segment display used by you is Common Anode, am I right in my assumption ? Also, is there a facility to show only 3 or 8 instead of 003 and 008? Would like to hear from you.
That is correct it is common anode. If you do not want to use leading yeros you just need to push in bunch of "1"s into the register then no segment would be lit. In a meantime I created won more video on shift registers. I would encourage you to watch it as well. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-sQfghvHYTlk.html
Hello. Very nice video. Just one question: in my experience I found out that obsolete digit is place at end of digits array, eg: digit[0] = {1,1,1,1,1,1,0,0}. It might be just that my design is different but i couldn't find the difference. Pls let me know what do u think :)
You are right. I did video in this way. Actually in 7 segment display you have no obsolete bit. The 8th bit represents dot. It is an old video of mine and I would do it differently now. But the great thisng is that you can come up with your own bit order and make it work as well. PLease check by newer video on this topic ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-sQfghvHYTlk.html
Thank you for this video.... I always am hearing about shift registers.... but I have only used mcp27013... not sure which is better... but I assume shift register is cheaper... any thoughts on this comparison?
I have never used mcp27013. I believe it extends number of output pins of Arduino. It is a complitly different concept . I will try to look at mcp27013 and let you know which one I would prefer.
@@marios_ideas it's i2c and each pin can be configured as input or output... I guess there is a library that must take up program memory ( Wire.h ) ... I wonder how big it actually is
It is common anode. And you decide What is going to be displayed on each display by pushing in the right combination of burd. If you do not want to have leasing zero you push in 00000000 instead of bit representation of zero. If you want to have characters you need to make out the bit representation (which segments schould be lit) for those characters. If you want to use 3 registers then you push in 24 bits instead of sixteen
You can use both. For common cathode you lit segment by sending high signal to appropiate pin. If you deal with common anodę then you lit the segment by sending low signal. Check the code and from it it will be apparent which tyle was used.
Yes it would. I use it sometimes. But in this setup the brightness of the segments will depend on the number of segments concurrently lit when using a single current limiting resistor connected to the common cathode. When multiple segments are illuminated simultaneously, they will share the current flowing through the resistor. As a result, the current is divided among the lit segments, potentially reducing the brightness of each segment compared to when they are individually lit.
can I extend this for a 6 digit clock? Chain-connect 6 shift registers for 6 7-segment displays? Or is there a better solution? Thanks for the video, very clear information!!
I'm also looking for this, but I think 6 7-segment display bundle (all in one) are way more efficient, than just 6 times 1 seven segments display bundles, but I didn't look up yet how to wire them with shift register as there is another type of wire selection to make, but it's dooable (I think there are even simpler bundles with integrated components to the display, like TM1637 ? 4 wires for 4 digits ?)
Yes you can but with this many it is better to use MAX7219 chip. I have video covering sort of this topic . ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-SGjQ-E3UD7A.html look at the code and change it to use two moe rows for 2 extra digits . You can use ready to use module www.aliexpress.com/i/32795462309.html You can also buy ready to use modules but I could not see 6 digit ones ony 8 digit ones. But I am sure I have seen one in the past just cannot find one now
Hi, I am still confused in the first code. You said that if you write HIGH in DS and SHCP, it will then throw HIGH in the storage register. But in the code - if(digits[Digit][i]==1) digitalWrite(DS_pin, LOW); isn't it a bit contradicting? I am very bad at programming, can you please enlighten me? Thanks in advance.
This is a common cathode matrix so you light the led by sending low signal. In the table where I store digit info the pixel that needs to be lit is represent by one . So in this if statement i invert the state
This is the delay in between displaying different digits. Without it all digits will be displayed one by one with no delay in between which for your eyes it would seem like all segments are lit all the time
Hello Sir iam Electronic Weighig Scale Manufacturer. In our weighing scale the weight shows on 6digit seven segment display which has 14pin. I want to reduce the no of pins by using hc595 ic. Is this able to do 14 pin to 4pin? Please suggest me
So you are using multiplexing. If I get you right you are using 14 pins of the microcontroller (6digits +8 segments A-F and a dot). Shift registers would work but you would need 6 shift registers chain connected. Then you would need 3 pins on the microcontroller. I would do it differently however. I would use MAX 7219 chip that allows you to make 8x8 matrix of leds so 6x8 that you would need would work perfectly. Check my video ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-SGjQ-E3UD7A.html There are libraries available which make it really simple. That was one of the videos I was planning to make. You can buy ready to use parts pl.aliexpress.com/item/1326009025.html?spm=a2g0o.productlist.0.0.e6136980polRxz&algo_pvid=12c063d7-f1ca-4f6c-96ed-61c73e794136&algo_expid=12c063d7-f1ca-4f6c-96ed-61c73e794136-1&btsid=2100bb4a16140144265718605e526e&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_
Ohm law(U=I*R). You take the average LED current consumption (ex 20mA) and the forward voltage (ex 3V) and you calculate U=3V, I=20mA => R=3/0,02=150 ohm
Hi Mario please help! I have an electronic bingo board from the 1980's. It has 2 boards each with two 7 segment displays. One board has the chip and then connects the power and data to the other board. The main board with the chip has 3 wires that connect to the main bingo board which gives it its power and data. The wires had been cut so I asked my electrician friend to test it for me. He put some thin wiring to the bingo board and then to the 3 wires but nothing happened. I am worried we fried the chip incase he sent 5v in the data in cable. But since then I took it to an electronic specialist and he has connected it to 5v and all four 7 segment displays are counting in unison 0-9. Does that mean the chip is ok since it is counting like in test mode, is it the chip making it do that? Or if it was fried would it not count anymore?
@@marios_ideas Hi again Mario, you were absolutely right! We re-wired the pcb with the chip and digitals correctly and connected it to the compatible bingo board and it works as it should. Displays the numbers perfectly! Thanks again :)
Hi Mario, I like your work, using registers for 7 digit display common anode. Do you have schematics on how to connect common cathode 7 digit display? I look forward to your reply. Thanks!
Well the connection would be the same. Only difference is that the common pin of the display would go to ground . The code then has to be changed . You have to change 0 to 1 and 1 to 0 in table representing the digits
Hi, I think I have an issue with the shift register. am using TPIC6C596 shift register and this register is capable of sending 8 bits. When I start sending 8 bits, I am getting only the last bit (i.e decimal point). But without the 8th bit (decimal point), my shift register can transfer whole 7 bits at a time. May i get the solution for this? When I implement in the proteus I am getting proper output. while doing the same in the hardware, I face the issue. For example, 0b00000110, I am getting the value as 1. if i do, 0b00000110 | 0b10000000, I am getting only .(dot) without 1. I should get 1.(one + dot). shiftOut(DS_pin, SHCP_pin, MSBFIRST, dec_digits[(buf[i] - 0x30)]|0x80); What will be the issue.? 0r my doubt is when supply goes to decimal point, all the other pins goes to OFF condition. When supply don’t go to the decimal point, all the other pins goes to ON condition. Is that correct?
You should get 1 with a dot when pushing 0b10000110 if that does not work then there is something wrong. Also mind in my video I did not even connect decimal point. I just posted a new video where I design and order PCB for this. There I include DP. When this board arrives I will make a follow up video where I will use DP as well
Apart from Mapping for each digit in the table you have to add to the table one more row where only segment G is set , which will represent minus and then in the code you need to add logic that checks if the number is negative and if it is you need to set the most significant digit/7seg display to minus
I have two displays that each have 3-digits. They are multiplex and each have 12pins. What would be the best way for me to control them in a project? Should I buy multiple external drivers? Or just a bigger arduino controller?
@@marios_ideas Yes, here is a link to the data sheet. www.silicon-ark.co.uk/datasheets/hp5082-7400-7430-display-hewlet-packard.pdf It is the HP 5082-7433 bubble display, the schematic and pinout is on the last page. They seem to have 11 active pins, and I am wanting to reduce the number of pins, so I have some free room on my arduino. Here is a video of a special driver someone made, to reduce the pinout to make it easier to attach to the aurdiuno: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-qx0lQD_BhHU.html I am planning to have one of the displays show voltage, and the other to show current. Thank you for the help.
@@izzyramos-gunn9895 The answer is max7219 chip. Check my video ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-IiWhnIhf-uUh.htmlttps://ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-QI1IJLB42G8.html and let me know if it helps
@@marios_ideas I ordered a 5 pack of the max7221s. They work well, and have a lot of features. I was originally going to buy shift registers, but the max7219 seems to be popular. Looking at the data sheet, it seems to be a shift register with other features. Thanks for the recommendation. This is the perfect chip for my project. They work well.
Hello, its a nice video and I have learnt quite a lot from it. I however have a doubt, if I need to make it a count down timer with 3 digits, I would be needing a third shfit register. This is clear, but what changes do I need to make in the code? For Eg. I need to count down from 399 to 0 or 198 to 0. Would appreciate inputs from your end to clarify further and make it wholesome..
@@marios_ideas Thanks Mario, I will update the details on the project here. I have another query for you. a. Does any of the data, clock and latch pins need pull up resistors ? b. what about the serial out pin of the first 74HC595 and the serial in pin of the second 74HC595? Do they need any for stable and reliable operation?
@@madhavdivya No. There is no pull up resistors. As the state of the connection is always know, it is either high or low. In case of e.g. using push buttons you need pull up resistors as when not pressed button is like a loose wire, and such flaoting connection has to be pulled either up or down. I have never experienced stability issues when daisy chaning the shift registors.
I do not have any PIC microcontrollers. I concentrate on Arduino. But I have a separate tutorial for 74ch164 ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-sQfghvHYTlk.html
It is entirely up to you. This shift register was made, i think to control 7 segments display, and with 8 pins can control 7 segments and a dot. As you can see in my video I ignored the dot. But you can also e.g. control 14 segment display en.wikipedia.org/wiki/Fourteen-segment_display. Here you would need 2 shift registers but use only 14 pins out of 16.
Hi friend. First of all, congratulations on your video, it is very interesting, I would like to do the same but with two CD4094 integrateds, since it uses three wires, and I would like to light a row of 16 LEDs independently. I would put a 12F675 and two 4094, if you could send me a code a style of the page in CCS. The issue is that I of those 16 led's, because I want to turn on the led 3-4-5-7-8 for example and then if I press a button turn on the 1-10-11-14-16, for example. It is to address an integrated PLL the MC145151-2 and thus change the frequency of a station from RX to TX. , when pressing the button it would be TX and when releasing it, it would go to RX. and so I change the frequency. Awaiting your reply and help, thank you in advance. Regards.
Do not have the experience with the microcontroler you plan to use and also never used the shift registers you mention. So not sure how can I help. For programing up to 64 leds I think MAX7219 is also a great option. You then use just one chip rather then cascading two shiftregisters. Controlling what you want to display is also a bit easier. Did not fully understand what code do you want me to send to you
Hey Mario, thank you for your very helpful Video, I am writing my Thesis now. I might need some screenshots from your Video. would it be Ok for you if I used them and I will tag you in my thesis?
You mean this one? pl.aliexpress.com/item/1005001297960517.html These modules have dedicated library. If you wanted to control a single display for one digit/character you can do it yourself using 2 shift registers but it is a lot of connections each of 16 segments needs to have its own resistor. If you were to wire 4 of these that would be 8 shif registers and 64 resistors. Good luck:)
I have one more video on this topic. Not sure you have seen it ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-sQfghvHYTlk.html . Consider supporting my channel. I give info how you can do it in most of my videos:)
I used 220Ohm resistors as I had those. I did not calculate the exact value of the resistor. With simple led project s I use either 220Ohm or 330Ohm resistors and both do the trick
@@marios_ideas I'm getting in the habit of using resistor arrays, as I'm getting sick of having to wire up individual resistors! Thank you. Also, I tested my 7-segment display, and it is a common cathode: When I ground either of the common pins, then touch one of the (cathode) pins, a segment lights up. You're using a common anode LED segment. Wiring for mine is going to be (a little) (a lot) different. I've never used a 7-segment LED, and its only the second time I've wired up a shift register. And, can any pins be used for DC/latch/clock? Thank you!
Funny enough I was just working on the video that may have some guidance for you. Check ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-9a5q-xDvZQs.html Obviously you have to adapt it to whatever you want to do but the coutdown is explained there
The video looked good but the "music" in the background was so irritating and distracting that I couldn't keep watching. Why do people insist on sabotaging their videos like this? Music, even if it's tasteful, never enhances instructional videos.
Well you get better over time. I am still putting music background but it volume is waaaay down. Can you check one of my recent videos and let me know if it still puts you off
