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Reading 2 digit 7 segments with ESP32

StealthRT

Member
I have been trying to contact a forum member that has done a modification to his pool equipment in order to control it remotely instead of having to go to the box every time and check on the codes. His has released the source code on his github page.

However, I have a different model than he does so I do not think his ESP32 code will work on mine.

His equipment contains a TM1650 for the 2 digit 7 segment display. I am unable to find out if my version has the TM1650 or something else.

His schematic looks like this: [IMG]

[IMG]

I have all the components that are displayed in the schematic. I have the ESP32 and the Level shifter.

[IMG]

Another forum member had the same chip but some pins were different. His schematic looks like this: [IMG]

So, since I do not have the same setup as they do is there any IC I can get that would make reading the 2 digit 7 segments easier than trying to read each led and determining what letter/number is being displayed? I can use the 4n25/35 optocoupler to "press" any of the 6 buttons and have an analog read for the 8 LEDs to determine which ones of those are on. The only trouble I foresee is the 2 digit 7 segments reading.


Note: Also posted to the following forums:
Reading 2 digit 7 segments with ESP32
https://www.electronicspoint.com/forums/threads/reading-2-digit-7-segments-with-esp32.297108/ https://forum.allaboutcircuits.com/threads/reading-2-digit-7-segments-with-esp32.186817/
https://www.eevblog.com/forum/projects/reading-2-digit-7-segments-with-esp32/new/#new
https://www.electronics-lab.com/com.../48746-reading-2-digit-7-segments-with-esp32/
 
Last edited:

Pommie

Well-Known Member
Most Helpful Member
As both boards contain a 4 pin connector it's most likely they communicate the same way. Power and an I²C (kinda) interface would be the 4 connectors. Does your board have a 16 pin SMD IC on the back and does it have a number?

Mike.
Edit, assuming the picture above is the back of your board then it does contain a 16 pin IC. Can you read the number?
 

StealthRT

Member
As both boards contain a 4 pin connector it's most likely they communicate the same way. Power and an I²C (kinda) interface would be the 4 connectors. Does your board have a 16 pin SMD IC on the back and does it have a number?

Mike.
Edit, assuming the picture above is the back of your board then it does contain a 16 pin IC. Can you read the number?
I'm unable to see any lettering on the chip itself.
 

Pommie

Well-Known Member
Most Helpful Member
Sometimes wetting it with your finger makes it readable.

Mike.
Edit, unfortunately they appear to have covered it with something. Can you get that off and take a clearer picture?
 
Last edited:

Pommie

Well-Known Member
Most Helpful Member
Can you get a clearer picture? The digit commons appear to go to the correct pins but it's hard to see the other tracks.
Reading individual LEDs is not going to be possible as they're multiplexed.
Intercepting the communication with the chip is the best method.

Mike.
 
Mike appears to be right. The two left-most pins on the 4 pin connector could be I2C. There are pullup resistors for each next to the connect.

The 3rd pin from the left is V+, the 4th ground.

Screenshot_20220511-190637_Edge.jpg
 

StealthRT

Member
Alright ill put the circuit components onto a breadboard and try out the I2C and see if it is the same. I gather that the far-right pin is the ground (under the C3) while the pin to the left of it would be the 5vdc?
 

StealthRT

Member
So I'm looking at my version of the ESP32 that I have (Known as the Lolin32)
1652416286050.png


And looking at their schematic I see that they call out GPIO 16, 17, 18 & 19. However, I do not have the same pin layout as they do...Go figure...
- GPIO 19 -> SWG main board clock
- GPIO 18 -> SWG main board data
- GPIO 17 -> Display board clock
- GPIO 16 -> Display board data
1652414673058.png


So, I take it my layout would be:

GPIO 19 -> GPIO 19 MISO
GPIO 18 -> GPIO 18 CLK
GPIO 17 -> GPIO 17 TX
GPIO 16 -> GPIO 16 RX

That look correct?
 

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