ESP32 connecting, but not quite connecting

[bitbank2]

ESP32 connecting, but not quite connecting

[bitbank2]

If the blue LED lights up and stays on, the connection should be solid. The printer's communication protocol may not be compatible and that would prevent it from working beyond connecting. Try connecting to it from a simple BLE app like Nordic's nRF Connect and just sending it ASCII text followed by a carriage return. It should print simple text directly. If that works, then I'm not sure what the problem is without seeing the rest of your code.

[davide1a]

Thanks for the quick reply. I got the nrf connect app (on my phone, is that what you meant?) connected to the printer, but to be honest I really don't understand any of it :( I've attached some screenshots of what it shows, but I don't know how I should send it anything to print. If it's any help, I have another Bluetooth printer app that works with it, and the code I'm running is just the demo code from the library.

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On Mon, Feb 6, 2023, 12:57 Larry Bank ***@***.***> wrote: If the blue LED lights up and stays on, the connection should be solid. The printer's communication protocol may not be compatible and that would prevent it from working beyond connecting. Try connecting to it from a simple BLE app like Nordic's nRF Connect and just sending it ASCII text followed by a carriage return. It should print simple text directly. If that works, then I'm not sure what the problem is without seeing the rest of your code. — Reply to this email directly, view it on GitHub <#42 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/A2UWDN4UNEXQS5P3GHQMGYLWWDYLLANCNFSM6AAAAAAUSUQOLQ> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[bitbank2]

hmm - if you're running the code successfully on another printer, then it sounds like the protocol of the failing one is different. If you're not familiar with how the code works, then it will be challenging to diagnose the problem remotely. Printer vendors either use the standard printing protocol (like the MTP-2) or they go it on their own. Can you send a purchase link to the one you're having trouble with? Maybe I'll buy one to figure out the issue.

[davide1a]

Sorry, I didn't mean the code was working on another printer. I meant I have another app on my phone (just called Bluetooth Print) that works with this printer.
The printer is one of these: https://www.tomtop.com/pt/p-os1228uk.html?currency=EUR&Warehouse=CN&aid=gttpmaxptth&gclid=Cj0KCQiA54KfBhCKARIsAJzSrdoLMBOW7jGu-iI_cN29RniFMp02ffVEvifo-S74sCrAGvIVnX3cy9gaAr_nEALw_wcB

[bitbank2]

I have and support that printer; I forgot because I have so many. Now I'm really curious as to why you're unable to get it working.

[davide1a]

That's why I was a bit unsure when it didn't work, too, as I saw you specifically have the MTP-3 in the list.

Could it be anything to do with any other settings for the ESP32? I've only used arduinos before - this is my first attempt with an ESP32 and I see there are lots of extra settings under the tools menu of the arduino IDE, that I don't understand yet. Currently, I'm using the "ESP32 Dev Module" board setting, as per the attached guide for the devices I have.
ESP-32 Dev Kit C V2_EN.pdf

If it helps, this is what I get from the serial monitor when restarting the device:

15:33:03.586 -> ets Jun 8 2016 00:22:57
15:33:03.586 ->
15:33:03.586 -> rst:0x1 (POWERON_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
15:33:03.586 -> configsip: 0, SPIWP:0xee
15:33:03.586 -> clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
15:33:03.586 -> mode:DIO, clock div:1
15:33:03.586 -> load:0x3fff0030,len:1344
15:33:03.586 -> load:0x40078000,len:13836
15:33:03.586 -> load:0x40080400,len:3608
15:33:03.618 -> entry 0x400805f0
15:33:03.976 -> Preparing image buffer...
15:33:03.976 -> Scanning for BLE printer
15:33:09.682 -> Found a printer!, connecting...

And that's as far as it gets. That's running the Thermal_Printer_Demo sketch, with the only change being specifying the device name in the scan.

[bitbank2]

Looks ok. I need to retest. Each time Espressif releases an updated support package for Arduino they break something. What version of ESP32 support are you using? I'll retest with your version to see if I can reproduce the problem.

[davide1a]

It's on 2.0.6 I can try an older version maybe. <https://www.e1a.pt>

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On Mon, Feb 6, 2023 at 3:53 PM Larry Bank ***@***.***> wrote: Looks ok. I need to retest. Each time Espressif releases an updated support package for Arduino they break something. What version of ESP32 support are you using? I'll retest with your version to see if I can reproduce the problem. — Reply to this email directly, view it on GitHub <#42 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/A2UWDN4VX7CK4U2XV6AU53DWWENBDANCNFSM6AAAAAAUSUQOLQ> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[davide1a]

I've tried the previous few versions, and it seems to be the same.

[bitbank2]

ok, thanks for the info. I'll test on my equipment.

[davide1a]

Thanks a lot. Hope you manage to find something!

If it helps, I've been playing a bit more, and with the demo sketch it just stops at "found printer, connecting" so I tried adding the following into the main loop, just to see if it was freezing completely, or if it was still running and maybe would try to connect again:

void loop() { // put your main code here, to run repeatedly: delay(5000); if (tpIsConnected()) { Serial.println("Still Connected"); tpSetFont(1, 0, 0, 0, 0); tpPrint((char *)"9x17 plain text\r"); } else if (!tpIsConnected()) { Serial.println(tpIsConnected()); tpConnect(); } }

With this, it does carry on trying, and after a few attempts, it does say "connect failed":
18:29:38.516 -> Scanning for BLE printer
18:29:44.184 -> Found a printer!, connecting...
18:29:49.742 -> 0
18:29:54.739 -> 0
18:29:59.733 -> 0
18:29:59.733 -> Connect failed
18:30:04.722 -> 0
18:30:04.722 -> Connect failed
18:30:09.739 -> 0
18:30:09.739 -> Connect failed
18:30:14.751 -> 0
18:30:14.751 -> Connect failed

So, it seems to be that the printer thinks they are connected, but that information isn't getting sent back to the esp for some reason.

[davide1a]

I've been fiddling a little more (just because I'm bored!) and getting some strange stuff now.

First off, I did manage to get nRF connect to send text to the printer, it's just that it would only work if i sent enough text to run over one line.

Then I tried stripping the code right down to just the following:
void setup() { // put your setup code here, to run once: Serial.begin(115200); Serial.println("Scanning for BLE printer"); if (tpScan((char *) "MTP-3", 5)) { Serial.println("Found a printer!, connecting..."); if (tpConnect()); { Serial.println("Connected!"); tpSetFont(1, 0, 0, 0, 0); tpPrint((char *)"9x17 plain text with lots of text so it goes over one line\r"); } } Serial.println(tpIsConnected()); }

Oddly, it is now getting as far as the "Connected!" line, but still doesn't print anything. Then, when it prints the IsConnected check at the end, it comes back as false. But I'm also now getting other lines on the serial monitor that I haven't seen before:

18:25:48.662 -> Scanning for BLE printer
18:25:54.592 -> Found a match for MTP-3
18:25:54.592 -> Printer type = 1
18:25:54.592 -> Found a printer!, connecting...
18:25:55.844 -> Came back from connect
18:25:56.329 -> Connected!
18:25:56.329 -> 0

I have no idea what's going on! Is it likely I just have a weird messed up printer? Do you think it's worth me getting a different one? If so any particular one you recommend?

[bitbank2]

I just tried it with my MTP-3 and an Arduino Nano 33 BLE. I added the name in the tpScan() method and it immediately found the printer and successfully printed.

[davide1a]

This is with an esp32 though. I don't have any Bluetooth adapters for the arduinos.

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On Wed, Feb 8, 2023, 19:33 Larry Bank ***@***.***> wrote: I just tried it with my MTP-3 and an Arduino Nano 33 BLE. I added the name in the tpScan() method and it immediately found the printer and successfully printed. — Reply to this email directly, view it on GitHub <#42 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/A2UWDNZGK5VZ6QASYPUSO4LWWPYJHANCNFSM6AAAAAAUSUQOLQ> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[bitbank2]

I just tested it with the ESP32 (generic LOLIN32 board), and it worked perfectly.

[davide1a]

Maybe I'll try a different printer then. Still don't understand where the extra lines were coming from in the serial monitor though.

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On Wed, Feb 8, 2023, 20:41 Larry Bank ***@***.***> wrote: I just tested it with the ESP32 (generic LOLIN32 board), and it worked perfectly. — Reply to this email directly, view it on GitHub <#42 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/A2UWDN3EI5OOIT5SDD2Y4M3WWQAHVANCNFSM6AAAAAAUSUQOLQ> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[davide1a]

Looks like I might struggle to get another one locally. In the meantime, if you get bored and if it helps, I loaded the demo code again with the core debug mode set to debug and verbose, so I don't know if those might show any reason for it not working?

esp32_thermal_printer_debug.txt
esp32_thermal_printer_verbose.txt

[davide1a]

I did manage to find another printer. A PT-210. It still doesn't find it automatically, I have to add the name (in this case "MTP-II_7867"), but then it's exactly the same. It gets as far as connecting (bluetooth indicator comes on), but still doesn't print anything.