Aliexpress Delta 2A and ESP32 DevKitC-32 Not Transmitting Consistent Data.

[Raman995]

I am using the DevKitC-V4 Driver Board from Maker's Pet, but some components that are not. Earlier I had bought these esp32 from amazon:
https://www.amazon.com/ESP32-DevKitC-32-Development-Supporting-Bluetooth-Interface/dp/B0DYDN5X1Z/ref=sr_1_1_sspa?dib=eyJ2IjoiMSJ9.VdSFSEE9ihQpM1t3PE8E5DgryooPM96AF5D0vhIkh6Z1ubsiD11bphhfJhgllTrwCv19iN3to_p6v2MBXmX43sHhEKqgge9wbcyhG6zkQNOUM3mDr4gXk-l5mdCTpbfeAMKTbYlfWJif1SGxCXwZyvXsEoIpZmUikaFSgg9pZxnXarZ--vCHbcWgI5PMGzc5kjMki7gB-ijOjJR4nXerjqqY1Z-2hLWv19LnAqBByE8.zzlYsXSp0KWHCY-KcSglzQ4Do0IqgZB9fx_U9zupEbk&dib_tag=se&hvadid=816714676759&hvdev=c&hvexpln=67&hvlocphy=9194503&hvnetw=g&hvocijid=13183934687854578681--&hvqmt=b&hvrand=13183934687854578681&hvtargid=kwd-2423719179270&hydadcr=13898_13840361&keywords=esp+32+s3+devkit&mcid=a6c04d0077ae379da0b55b62ceab72f5&qid=1786574549&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

The esp32 did not fit into the driver board, because the esp32 is too skinny by one pin. When placing the esp32 into the driver board, the amount of pins is correct, but only half of the microcontrollers pins can be connected to the driver board. In the picture attached called "esp32 fitment", you can see that the left pins of the esp32 are aligned with the driver board connectors, while the right half are not.

The battery I used came from the Elegoo Smart Car Kit v4.0, and is rechargeable with a voltage of 7.2V-8.4V depending on the charge.

I previously was attempting to connect and receive info from this lidar:
https://www.aliexpress.us/item/3256806679277463.html?spm=a2g0o.productlist.main.3.745dDkpZDkpZZg&algo_pvid=76020f58-a190-411a-9edc-1be778261bb7&algo_exp_id=76020f58-a190-411a-9edc-1be778261bb7-2&pdp_ext_f=%7B"order"%3A"5"%2C"eval"%3A"1"%7D&pdp_npi=6%40dis!USD!56.19!6.54!!!401.10!46.71!%402141115b17558065191563092ed979!12000038558628042!sea!US!0!ABX!1!0!n_tag%3A-29910%3Bd%3A838d0660%3Bm03_new_user%3A-29895%3BpisId%3A5000000174221209&curPageLogUid=sRhtkFEdZ97c&utparam-url=scene%3Asearch%7Cquery_from%3A%7Cx_object_id%3A1005006865592215%7C_p_origin_prod%3A

It looks identical to the Delta-2A, and has the same pins as it. I used the LDS library, and first tried the all_lidars_lds02rr_esp32 example, with both versions of the Delta-2A. That yielded no results, and although it said that the initialization was successful, I never received any data. I tried each of the models supported by the library, and that did not work. Later I tried using the delta_2a_115200_esp32_debug example, where the same occurred. I figured it could be a speed mismatch, so I wrote a program that would simply read the serial output and continuously change the lidar motor speed, which didn't detect any data. Finally I used a program that kept the motor at full speed, and when I unplugged the motor +5V pin and plugged it back in I received data.

When the motor shut off, it printed:
D7 E1 F5 6C EF 05 FF 81 80 01 00 00 00 E4 00 FA 00 80 01 00 E0 00 FC 00 00 D0 01 00 00 FF 01 00 00 FE 01 00 00 E0 05 00 00 F4

When it turned on again it printed:
05 00 00 00 00 80 20 00 00 00 FD 0D 0A C9 EE DB DA CA D0 C9 BC B4 A8 BB FA C6 F7 C8 CB BF C6 BC BC D3 D0 CF DE B9 AB CB BE 0D 0A C8 ED BC FE D7 F7 D5 DF A3 BA 4A 4C 20 57 61 6E 0D 0A B9 CC BC FE B0 E6 B1 BE 3A 20 4C 44 53 33 5F 4E 4F 52 5F 4D 61 79 20 20 34 20 32 30 31 38 31 35 3A 33 36 3A 33 34 0D 0A AA 00 33 01 61 AC 00 2B 32 30 33 39 33 36 33 38 35 30 34 31 35 37 30 35 30 30 33 31 30 30 33 38 4C 44 53 33 5F 4E 4F 52 5F 31 38 30 35 30 34 31 35 33 36 0B A6

And the data ends there. I ran the serial monitor at 1000000 baud, and the lidar serial at 115200 baud. Is there any way to get a consistent data stream? Thank you for your help!

delta_2a_115200_esp32_debug.txt

[makers-pet]

Hello,

Thank you for the hex dump and the photos. Here are some comments

• I've checked your LiDAR wiring based on your photos; the LiDAR wiring looks correct
• the genuine ESP32 DevKitC V4 has exactly 1" pin row spacing (which Maker's Pet driver board matches exactly)
  • your Amazon ESP32 module width (and pin row spacing) is ~1mm less than the genuine ESP32 DevKitC V4
• your "motor off" data is not valid, let's ignore it
• your "motor on" data is valid
  • It prints a 3irobotix boot banner in Chinese using GB2312/GBK encoding followed by
    深圳市杉川机器人科技有限公司 - "Shenzhen 3irobotix (Sanchuan) Robotics Technology Co."
    软件作者：JL Wan - "Software author: JL Wan"
    固件版本: LDS3_NOR_May 4 2018 15:36:34 - firmware version
  • followed by a Delta protocol packet with a valid checksum immediately after

AA 00 33 01 61 AC ... 0B A6
start=0xAA  len=51  proto=0x01  type=0x61  data_type=0xAC
payload(ascii) = "203936385041570500310038 LDS3_NOR_1805041536"   (serial no. + firmware id)
checksum 0x0BA6 — computed 0x0BA6, MATCH

So, your TX, +5V, GND wiring and baud are correct.

Possible problems

• LiDAR rotation speed has to be ~5 Hz. Faster or slower may cause the Lidar to stop sending data.
• serial data gets corrupted once LiDAR spins up

I'd suggest testing like this

• twist your LiDAR cable wires together - sometimes this makes serial transmission more reliable, especially when wires are long
• don't use PWM for now
  • if you can, take a variable DC power supply, connect to LiDAR MOT+ and MOT-, set DC voltage to get ~5 rotations per second.
  • if you don't have a variable DC power supply, try powering the LiDAR using 5V straight, then (briefly - not to burn the motor) slow down the LiDAR puck using your finger to ~5 revolutions per second.
  • keep running your serial capture while you are doing that
  • check if you get data

[Raman995]

Thank you for your help! I've attempted all of the solutions, and it seems at least one part of my setup is defective. I've decided to simply purchase the components from the Maker's Pet website. Since I already have the Driver Board for ESP32-DevKitC-V4, is it compatible with the ESP32E 30-pin Development Board that Maker's Pet sells, or is there a specific 38 pin ESP32 that I can order? I noticed that the Delta-2A and the LDS02RR are the same price on the website. What is the difference, and is one better than the other?

[makers-pet]

Hi @Raman995 ,

ok, makes sense. To answer your question,

• "is ESP32-DevKitC-V4" compatible with ESP32E 30-pin board? No, ESP32-DevKitC-V4 expects 38-pin ESP32, not 30-pin
• "is there a specific 38 pin ESP32 that I can order" - I think I have one ESP32 38-pin that fits the Driver Board that I can ship. If you order ESP32E, I can ship you the 38-pin ESP32 instead.
• "Delta-2A and the LDS02RR ... What is the difference" - both are roughly similar in size, performance, but personally I'd recommend LDS02RR. Not because it's better in some way, but because I've used it a lot more than Delta-2A and LDS02RR has always been reliable for me personally.
  • The real difference is LDS02RR can be connected directly to ESP32 (all types, 30 or 38 pin) without the Driver Board at all. This is because LDS02RR ships with a little adapter board included - and that adapter board converts PWM to motor on/off (same what the Driver Board does). That said, LDS02RR also plugs into the Driver Board just fine as well.

[Raman995]

Hi,
I attempted to buy the LDS02RR, ESP32E, and 2 N20 Encoder Motor 12V 200RPM, with 2 corresponding breakout cables from makerspet.com through Paypal, but it kept giving me this error: "r(...) is not a function". Is there any way around this?

[makers-pet]

Let me check. I've been getting PayPal payments, so this is a bit odd.

[makers-pet]

@Raman995 can you please try ordering again - from an incognito browser window (or regular window with cache cleaned)?

I've tested PayPal right now - it works for me fine. But the website did upgrade to Wordpress v7.1 yesterday. It's conceivable that the upgrade conflicts with your cached browser data.

[Raman995]

I tried ordering again both with a cleared cache, and from an incognito window, and it gave me the same error "r(...) is not a function". The Paypal window quickly flashes and closes before it even loads.

[kaiaai]

@Raman995 I really appreciate it. I've captured errors this time, looking at them now. Sorry about the trouble.

[makers-pet]

@Raman995, I've fixed the issue. Hopefully PayPal checkout should work now.

[Raman995]

Thank you, it worked this time! My order number is 4434.

[makers-pet]

Here is a demo of LDS02RR + ESP32 30-pin + motor driver board ESP32 DevKitC V4.

[Raman995]

In the video, I may be wrong, but it seems like the ESP32 is 38-pin, not 30-pin. In order number 4434, did you happen to ship it with the 38 pin or 30 pin ESP32?

[Raman995]

@makers-pet Thank you, the new parts are working! I linked the final setup.

I had some issues, but that was only due to the wrong pin setup. What worked in the end was EN = 32, Lidar RX = 27, Lidar TX = 35, and Lidar PWM = 13. It then gave me a steady output. I wanted to see a visual representation, but without using Docker or Linux at all, because I thought that was a very complicated process. I used a python file to visualize the results, and used a semi-optimized program on the esp32. The Visualizer.txt file is meant to be a .ino file, but Github wouldn't let me upload it as that.
Visualizer.py
Visualizer.txt

[makers-pet]

@Raman995 awesome!
FYI, if you want a simple connection and can use a Raspberry Pi, I maintain this Python library https://github.com/kaiaai/lds2d supporting 25+ 2D LiDAR models with tutorials https://makerspet.com/blog/tutorial-connect-xiaomi-lds02rr-lidar-to-raspberry-pi-python/ .