Good day dear sirs

I have a far terminal 24volt 7 segment display common anode connected to elevator control board
And need to decode its signal into Esp32 board so I can read it via IOT

What chip or circuit should I use to reverse the BCD system

Is there any chip work in reverse of 4511 or similar driver


Thanks in advance

 

Hi Fad,
Welcome to AAC.
If you can spare 7 Input pins on your ESP32, a simple sketch could recode the LED Bits.
E

 

Welcome to AAC!

What chip or circuit should I use to reverse the BCD system

Is there any chip work in reverse of 4511 or similar driver

Which are you working with? BCD or 7 segments? The former will be easier, but you need to define what you mean by "reverse decode".

If you're transmitting the data to an ESP32, why can't you use it to do your decoding?

 

https://www.cselettronica.com/datasheet/74C915.pdf and someone on Ebay has one for sale
https://www.ebay.co.uk/itm/404553383894 but they are not selling it cheap!
https://www.elektormagazine.com/magazine/elektor-197612/57792 if you want to do it in logic gates.

 

Hi Fad,
Welcome to AAC.
If you can spare 7 Input pins on your ESP32, a simple sketch could recode the LED Bits.
E

+1

 

Hi Fad,
Welcome to AAC.
If you can spare 7 Input pins on your ESP32, a simple sketch could recode the LED Bits.
E

Thanks for your response
First i apologies for mistyping i meant ESP8266 and need to use the maximum availability of gpio
Besides that I prefer to use chip as buffer protection with live 24 volt

But it's really a good idea and hope you can share a guidance about such sketch

 

Welcome to AAC!
Which are you working with? BCD or 7 segments? The former will be easier, but you need to define what you mean by "reverse decode".

If you're transmitting the data to an ESP32, why can't you use it to do your decoding?

Thanks for your response
As BCD located on far terminal of elevator control board so I can only deal with 7 segment output

Revere coding means to convert the 8 signals of 7 segment into 4 bit binary data and input it into ESP8266

As you know 4511 work as BCD
And Ifound 74tl148 which work as 8 to 3 convert but still can't figure out how to use it

 

The 148 is a 3:8 mux, which is not what you want. You are very unlikely to locate a chip that has the hardware you need, apart from the 74C195 as Ian suggests in #4.

Why not do it in software? The ESP8266 has plenty of I/O. Is there a reason you don't want to do that? It will be much simpler, at least in hardware.

 

As BCD located on far terminal of elevator control board so I can only deal with 7 segment output

How are you accessing the segment data? Are you connecting to the LEDs in the display? How many digits are you dealing with?

How is the data going to be sent to your ESP8266?

 

Here is a Sort of a round-about scheme, but feesd the seven signals into an 8-bit D/A cpmverter then use an analog input. You willthen need a small bit of code to convert from a voltage reading to a number.

 

The 148 is a 3:8 mux, which is not what you want. You are very unlikely to locate a chip that has the hardware you need, apart from the 74C195 as Ian suggests in #4.

Why not do it in software? The ESP8266 has plenty of I/O. Is there a reason you don't want to do that? It will be much simpler, at least in hardware.

In fact i just one pinnas an output to simulate ordering the cabin
Rest is free
But I'm just a beginner in coding and don't know where to start

I'll appreciate any guidance or sample sketch

 

Tha

https://www.cselettronica.com/datasheet/74C915.pdf and someone on Ebay has one for sale
https://www.ebay.co.uk/itm/404553383894 but they are not selling it cheap!
https://www.elektormagazine.com/magazine/elektor-197612/57792 if you want to do it in logic gates.

Thanks for the feedback dear Mr Lan
74c915 is what I need but its rare and can't find it at all

 

Why do you need to decode it? Can't you just assume that what you are reading is a 7-bit number, then use a lookup table in the ESP32 if you need to know the original number?

 

Why do you need to decode it? Can't you just assume that what you are reading is a 7-bit number, then use a lookup table in the ESP32 if you need to know the original number?

In fact thanks to you here is the first hint or key to know where to start
But can't find any relative sample so i edit it

I'm just a beginner

 

In fact thanks to you here is the first hint or key to know where to start
But can't find any relative sample so i edit it

I'm just a beginner

If you look at the 7 output as a binary number, you get 126,48,109,121,51,91,31,127,115 instead of 0,1,2,3,4,5,6,7,8,9.
In the ESP32 you have a 32-bit microcontroller operating at 160MHz - more power than a desktop computer of a few years back (about the same as a 486) Surely it can't be beyond the wit of man to get from one list to the other?

 

Totally agreed
Spit I'm using slower esp8266 but can't figure out how to form the right code

Is there any tutorials or documentation for that?
Link please

 

Writing even "simple" code is not a trivial task, as the TS tells us. That is a big portion of why I suggest using the computers whose makers use different words for everything than the rest of the world. Using seven inputs is not a trivial task, converting the 7 inputs to a decimal number is not trivial to a beginner.

 

Is there any tutorials or documentation for that?

Are you looking for a cut-and-paste solution? Your requirements may be a little specific for that.

Do you have ANY coding experience? Your first post would imply you do have, but it seems you do not. Reading seven digital inputs into a binary value and writing an if-then-else statement to look up the correct value as output is fairly trivial, if not very elegant.

What coding experience do you have? It would help in guiding you.

 

Are you looking for a cut-and-paste solution? Your requirements may be a little specific for that.

Do you have ANY coding experience? Your first post would imply you do have, but it seems you do not. Reading seven digital inputs into a binary value and writing an if-then-else statement to look up the correct value as output is fairly trivial, if not very elegant.

What coding experience do you have? It would help in guiding you.

it seems like it could be done with seven IF/THEN statements. But only if they allow the AND functions for the "IF" portion.

 

I would read the seven inputs as a 7-bit number, then use a SWITCH/CASE statement.
Note that there would have to be two versions depending on whether it is a common anode or common cathode display, and it would have to deal with 6s and 9s with or without tops and bottoms.