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  3. FLIR LEPTON 3.5 Thermal camera with VOXL 2

FLIR LEPTON 3.5 Thermal camera with VOXL 2

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  • VinnyV Vinny

    Hi @Jetson-Nano
    Happy to continue helping.
    Regarding your updated design first:


    "I2C Bus Configuration: Regarding the I2C bus, should the I2C lines be connected in parallel to both the Lepton Module and the I2C GPIO expander?"

    -- Yes.

    "Lepton Reset/Power Down Pins: Concerning the Lepton Module's RESET_N and POWER_DOWN_N pins, should the existing resistor-capacitor (RC) network connected to the RESET_N pin be retained, or can it be omitted?"

    -- We do not have any RC delay on the reset line since it is all GPIO controlled.

    "I2C GPIO Expander INT Pin: For the I2C GPIO expander, is it permissible to leave the INT (Interrupt) pin unconnected, or does it require termination?"

    -- It is an output and we do not use it, so N.C. is fine

    I2C GPIO Expander Software Configuration: From a software perspective, is the I2C GPIO expander a plug-and-play component, or does it require specific configuration?

    -- It is supported at that HW address by default with voxl-lepton-server (I think that it what is called, Alex can correct me if I'm mistaken)

    However, your updated SCH has a couple errors:

    • Your LDO input and output caps are not correctly done. They are in series, not shunts to GND as required:0f7551cf-b798-4665-9673-a4df6182c21b-image.png

    • The Pull-down R on the GPIO expander is not correct. The ADDR pin will always be HIGH due to the direct connection to 2.8V, but our default is LOW (see the snippet from above): f6ee80a1-e5fa-4635-b3dd-93c5ca85e501-image.png

    • Also, the GPIO expander is meant to drive the RESET input of the Lepton, not the PWR_DWN input: eb4012fd-2528-4879-a1f6-d235568faa6e-image.png

    Now, as to your existing board not powering on, I have a clue for you...
    Our very first lepton board we failed to notice the pin 1 hole in the Molex socket, and that is important since it sets a keying for the Lepton module. If the module is inserted incorrectly (90 or 180 off) it will clearly not power up. Pay close attention to the hole in the socket for pin 1 and two vs one slots in the socket which set the orientation.
    cc6af474-a14c-48b3-9d96-9310df3480ab-image.png
    679c78bb-4741-4674-9c33-277355fde4c9-image.png

    Keep us posted and hope this helped.

    Jetson NanoJ Offline
    Jetson NanoJ Offline
    Jetson Nano
    Veteran
    wrote on last edited by
    #15

    @Vinny @Alex-Kushleyev

    Thank you for your valuable feedback on the previous version of the schematic. Based on your recommendations, I have revised the design accordingly.

    Please find the updated schematic attached below for your review

    8b63651c-f927-48fd-9c33-16adf04c65ed-image.png

    In addition to the design changes, I have also revisited the hardware setup to verify the power delivery, the Lepton module is still not powering up—there is no shutter sound or I²C response. At this point, I have exhausted the immediate troubleshooting steps and would greatly appreciate your guidance on further debugging strategies.

    Could you please review the updated schematic and suggest any additional tests or possible points of failure that may have been overlooked?

    Thank you again for your support and expertise.

    VinnyV 1 Reply Last reply
    0
    • Jetson NanoJ Jetson Nano

      @Vinny @Alex-Kushleyev

      Thank you for your valuable feedback on the previous version of the schematic. Based on your recommendations, I have revised the design accordingly.

      Please find the updated schematic attached below for your review

      8b63651c-f927-48fd-9c33-16adf04c65ed-image.png

      In addition to the design changes, I have also revisited the hardware setup to verify the power delivery, the Lepton module is still not powering up—there is no shutter sound or I²C response. At this point, I have exhausted the immediate troubleshooting steps and would greatly appreciate your guidance on further debugging strategies.

      Could you please review the updated schematic and suggest any additional tests or possible points of failure that may have been overlooked?

      Thank you again for your support and expertise.

      VinnyV Offline
      VinnyV Offline
      Vinny
      ModalAI Team
      wrote on last edited by
      #16

      Hi @Jetson-Nano
      Sch updates look correct. I'd still add a pull-up on the Lepton Reset to help control it during initial power-ON before the IO expander is configured.

      To help further debug your existing setup, I'd need more tangible info such as pictures with all your cables, etc. Do you have a DMM handy showing the voltages of 1.2V and 2.8V, and an O-scope for the 25MHz?
      Can you also post a pic of your board without components installed (so I can review the layout as best as possible)?
      It's hard to give much further guidance without actual hardware in my hands.
      Thanks!

      Jetson NanoJ 1 Reply Last reply
      0
      • Jetson NanoJ Jetson Nano

        @Alex-Kushleyev @Eric-Katzfey @modaltb
        guys any help with solving this issue.
        this the video feed I am getting.
        589968ed-ccc6-443d-a925-a6f7f0aa41f8-Screenshot from 2025-06-25 19-11-15.png

        voxl2:~$ voxl-lepton-server 
        =================================================================
        spi_bus:         0
        spi_speed:       16000000
        en_i2c:          1
        i2c_bus:         4
        shutter_mode:    manual
        flow_shutter_s:  20
        closePeriodInFramesInAir:         0
        openPeriodInFramesInAir:          1
        desiredFfcPeriodMsInAir:          360000
        desiredFfcTempDeltaCentiDegInAir: 600
        assign_cpu_num:  7
        en_timing_msg:   0
        en_rotate:       1
        =================================================================
        existing instance of voxl-lepton-server found, attempting to stop it
        thread is now locked to the following cores: 7
        attempting to init the io expander
        Attempting intitialization for M0188 (TCA9543A)
        ERROR: in voxl_i2c_read_bytes, failed to write to bus
        io_expander_init, failed to read TCA9543APWR control register
        If you are not using an M0188 lepton board then this is expected
        Attempting intitialization for M0187 (PI4IO)
        ERROR: in voxl_i2c_read_bytes, failed to write to bus
        io_expander_init, failed to read from io expander
        If you are not using an M0187 lepton board then this is expected
        attempting to open I2C CCI
        trying address 0x2a
        successfully opened I2C port
        Successfully connected to I2C CCI
        waiting for first frame from lepton to create MPA pipes
        creating MPA server pipes
        enabling MPA control interface
        client "voxl-portal78592109" connected to channel 0  with client id 0
        client "voxl-portal64940239" connected to channel 1  with client id 0
        
        
        J Offline
        J Offline
        jared
        Contributor
        wrote on last edited by jared
        #17

        @Jetson-Nano did you ever figure out a solution to this? I'm getting similar imagery. Is this an FFC issue? Running the same breakout board on a raspberry pi produces completely normal imagery.

        K 1 Reply Last reply
        0
        • J jared

          @Jetson-Nano did you ever figure out a solution to this? I'm getting similar imagery. Is this an FFC issue? Running the same breakout board on a raspberry pi produces completely normal imagery.

          K Offline
          K Offline
          KLindgren
          Contributor
          wrote on last edited by
          #18

          To close the loop here: we solved our issue of seeing lines by providing power to the lepton via one of the 3.3V pins on the voxl2 mini instead of relying on the power pin of J10 on the sparrow board.

          VinnyV 1 Reply Last reply
          0
          • K KLindgren

            To close the loop here: we solved our issue of seeing lines by providing power to the lepton via one of the 3.3V pins on the voxl2 mini instead of relying on the power pin of J10 on the sparrow board.

            VinnyV Offline
            VinnyV Offline
            Vinny
            ModalAI Team
            wrote on last edited by
            #19

            Hi @KLindgren
            You raise a concern and something I will run by the team, but if you are powering the M0187 at 3.3V directly, you are violating the FLIR specs for the Lepton and our system design constraints.

            5ffb65bb-b699-4528-91b2-ccf9f9ddcc4d-image.png

            How are you connecting M0187 to M0188? Maybe your cable is introducing some extra losses giving you a lower than 2.8V supply?

            K 1 Reply Last reply
            0
            • VinnyV Vinny

              Hi @KLindgren
              You raise a concern and something I will run by the team, but if you are powering the M0187 at 3.3V directly, you are violating the FLIR specs for the Lepton and our system design constraints.

              5ffb65bb-b699-4528-91b2-ccf9f9ddcc4d-image.png

              How are you connecting M0187 to M0188? Maybe your cable is introducing some extra losses giving you a lower than 2.8V supply?

              K Offline
              K Offline
              KLindgren
              Contributor
              wrote on last edited by
              #20

              @Vinny apologies, I should have clarified we're using this PureThermal breakout board which regulates VIN from 3.3-5V

              VinnyV Jetson NanoJ 2 Replies Last reply
              0
              • K KLindgren

                @Vinny apologies, I should have clarified we're using this PureThermal breakout board which regulates VIN from 3.3-5V

                VinnyV Offline
                VinnyV Offline
                Vinny
                ModalAI Team
                wrote on last edited by
                #21

                @KLindgren
                OK, M0188 will not work with anything other than our M0187.
                Thanks for clarifying.

                J 1 Reply Last reply
                0
                • VinnyV Vinny

                  @KLindgren
                  OK, M0188 will not work with anything other than our M0187.
                  Thanks for clarifying.

                  J Offline
                  J Offline
                  jared
                  Contributor
                  wrote on last edited by
                  #22

                  @Vinny said in FLIR LEPTON 3.5 Thermal camera with VOXL 2:

                  M0187

                  Hi @Vinny - I'm guessing the M0187 is your FLIR breakout board? Do you sell these?

                  VinnyV 1 Reply Last reply
                  0
                  • J jared

                    @Vinny said in FLIR LEPTON 3.5 Thermal camera with VOXL 2:

                    M0187

                    Hi @Vinny - I'm guessing the M0187 is your FLIR breakout board? Do you sell these?

                    VinnyV Offline
                    VinnyV Offline
                    Vinny
                    ModalAI Team
                    wrote on last edited by
                    #23

                    Hi @jared
                    Presently they are integrated within certain drones...
                    https://docs.modalai.com/stinger-vision-datasheet/

                    I can poke the team to see if we can get it listed separately in the near future.

                    J 1 Reply Last reply
                    0
                    • K KLindgren

                      @Vinny apologies, I should have clarified we're using this PureThermal breakout board which regulates VIN from 3.3-5V

                      Jetson NanoJ Offline
                      Jetson NanoJ Offline
                      Jetson Nano
                      Veteran
                      wrote on last edited by Jetson Nano
                      #24

                      @KLindgren I am also using the same board but my video stream is with high disturbances, i have posted a image above in the chat. could you please share the image from your camera so that i could figure out what is wrong with my setup. Also the details of your setup, it would be of great help.

                      K 1 Reply Last reply
                      0
                      • Jetson NanoJ Jetson Nano

                        @KLindgren I am also using the same board but my video stream is with high disturbances, i have posted a image above in the chat. could you please share the image from your camera so that i could figure out what is wrong with my setup. Also the details of your setup, it would be of great help.

                        K Offline
                        K Offline
                        KLindgren
                        Contributor
                        wrote on last edited by
                        #25

                        @Jetson-Nano our images looked the same as yours when providing power to the PureThermal from the sparrow board (m0188) but using a 3.3V from the voxl2 mini fixed the issue and gives us this imagery.
                        94767b82-68c1-4a72-b830-64c29fc4d33e-image.png

                        We are using power from the voxl2 mini's J19 and currently working on running 2 leptons with an RGB using the sparrow board.
                        fdd0c8b1-0a2d-4496-b7a9-f5ab409f603f-image.png

                        Jetson NanoJ 1 Reply Last reply
                        0
                        • K KLindgren

                          @Jetson-Nano our images looked the same as yours when providing power to the PureThermal from the sparrow board (m0188) but using a 3.3V from the voxl2 mini fixed the issue and gives us this imagery.
                          94767b82-68c1-4a72-b830-64c29fc4d33e-image.png

                          We are using power from the voxl2 mini's J19 and currently working on running 2 leptons with an RGB using the sparrow board.
                          fdd0c8b1-0a2d-4496-b7a9-f5ab409f603f-image.png

                          Jetson NanoJ Offline
                          Jetson NanoJ Offline
                          Jetson Nano
                          Veteran
                          wrote on last edited by
                          #26

                          @KLindgren thank you for reverting back. From which port are you taking the 3.3 V also how did you complete the circuit, the image you provide is confusing with respect to the connections, it would be great if you would provide further details.

                          K 1 Reply Last reply
                          0
                          • VinnyV Vinny

                            Hi @jared
                            Presently they are integrated within certain drones...
                            https://docs.modalai.com/stinger-vision-datasheet/

                            I can poke the team to see if we can get it listed separately in the near future.

                            J Offline
                            J Offline
                            jared
                            Contributor
                            wrote on last edited by
                            #27

                            Thanks @Vinny

                            1 Reply Last reply
                            0
                            • Jetson NanoJ Jetson Nano

                              @KLindgren thank you for reverting back. From which port are you taking the 3.3 V also how did you complete the circuit, the image you provide is confusing with respect to the connections, it would be great if you would provide further details.

                              K Offline
                              K Offline
                              KLindgren
                              Contributor
                              wrote on last edited by KLindgren
                              #28

                              @Jetson-Nano Our 2 Leptons are connected as described in this image - though we're using PureThermal boards instead of M0187s for the Leptons. The 3.3V VIN is provided from the VOXL's J19 port via this cable and a "Y" split jumper we've soldered together.

                              1 Reply Last reply
                              0
                              • VinnyV Vinny

                                Hi @Jetson-Nano
                                Sch updates look correct. I'd still add a pull-up on the Lepton Reset to help control it during initial power-ON before the IO expander is configured.

                                To help further debug your existing setup, I'd need more tangible info such as pictures with all your cables, etc. Do you have a DMM handy showing the voltages of 1.2V and 2.8V, and an O-scope for the 25MHz?
                                Can you also post a pic of your board without components installed (so I can review the layout as best as possible)?
                                It's hard to give much further guidance without actual hardware in my hands.
                                Thanks!

                                Jetson NanoJ Offline
                                Jetson NanoJ Offline
                                Jetson Nano
                                Veteran
                                wrote on last edited by
                                #29

                                Hi @Vinny, @Alex-Kushleyev,

                                Thank you once again for your valuable feedback on the schematics, and apologies for the delayed response.

                                I’ve now completed the PCB layout based on the updated schematics and newly selected components, as per your suggestions. I would greatly appreciate it if you could take a moment to review the layout and share your feedback—particularly on whether it meets the required configuration or if any modifications are recommended.

                                The following have been included in the shared Drive link:

                                Screenshots of all four layers

                                3D views of both the top and bottom sides of the board

                                🔗 Drive link: https://drive.google.com/file/d/1czCx-N8ws3CelpKTV1VRBTzFZLcd-odx/view?usp=drive_link

                                Looking forward to your insights.

                                Thank you again for your continued support and guidance.

                                VinnyV 2 Replies Last reply
                                0
                                • Jetson NanoJ Jetson Nano

                                  Hi @Vinny, @Alex-Kushleyev,

                                  Thank you once again for your valuable feedback on the schematics, and apologies for the delayed response.

                                  I’ve now completed the PCB layout based on the updated schematics and newly selected components, as per your suggestions. I would greatly appreciate it if you could take a moment to review the layout and share your feedback—particularly on whether it meets the required configuration or if any modifications are recommended.

                                  The following have been included in the shared Drive link:

                                  Screenshots of all four layers

                                  3D views of both the top and bottom sides of the board

                                  🔗 Drive link: https://drive.google.com/file/d/1czCx-N8ws3CelpKTV1VRBTzFZLcd-odx/view?usp=drive_link

                                  Looking forward to your insights.

                                  Thank you again for your continued support and guidance.

                                  VinnyV Offline
                                  VinnyV Offline
                                  Vinny
                                  ModalAI Team
                                  wrote on last edited by
                                  #30

                                  Hi @Jetson-Nano
                                  I've been on vacation and just catching up. It will be a few days before I can get to this.
                                  Thanks for your patience.

                                  1 Reply Last reply
                                  0
                                  • Jetson NanoJ Jetson Nano

                                    Hi @Vinny, @Alex-Kushleyev,

                                    Thank you once again for your valuable feedback on the schematics, and apologies for the delayed response.

                                    I’ve now completed the PCB layout based on the updated schematics and newly selected components, as per your suggestions. I would greatly appreciate it if you could take a moment to review the layout and share your feedback—particularly on whether it meets the required configuration or if any modifications are recommended.

                                    The following have been included in the shared Drive link:

                                    Screenshots of all four layers

                                    3D views of both the top and bottom sides of the board

                                    🔗 Drive link: https://drive.google.com/file/d/1czCx-N8ws3CelpKTV1VRBTzFZLcd-odx/view?usp=drive_link

                                    Looking forward to your insights.

                                    Thank you again for your continued support and guidance.

                                    VinnyV Offline
                                    VinnyV Offline
                                    Vinny
                                    ModalAI Team
                                    wrote on last edited by
                                    #31

                                    Hi @Jetson-Nano
                                    I do not have access to the link you have above.
                                    Please reach out to us using the contact form https://www.modalai.com/pages/contact-us and we can get a more detailed review scheduled using your native cad tools which is more effective for us.

                                    Just mention in the form you wish to reach Vinny and then in the response from our team, you can reply with your data and they will forward it to me.
                                    Thanks!

                                    Jetson NanoJ 1 Reply Last reply
                                    0
                                    • VinnyV Vinny

                                      Hi @Jetson-Nano
                                      I do not have access to the link you have above.
                                      Please reach out to us using the contact form https://www.modalai.com/pages/contact-us and we can get a more detailed review scheduled using your native cad tools which is more effective for us.

                                      Just mention in the form you wish to reach Vinny and then in the response from our team, you can reply with your data and they will forward it to me.
                                      Thanks!

                                      Jetson NanoJ Offline
                                      Jetson NanoJ Offline
                                      Jetson Nano
                                      Veteran
                                      wrote on last edited by
                                      #32

                                      @Vinny

                                      Thank you for the update — I hope you had a great vacation!

                                      As you mentioned, I’ve submitted an inquiry through your contact form. Once I receive a response from your team, I’ll follow up with the necessary details and additional data as needed.

                                      Thank you for your continued support.

                                      VinnyV 1 Reply Last reply
                                      0
                                      • Jetson NanoJ Jetson Nano

                                        @Vinny

                                        Thank you for the update — I hope you had a great vacation!

                                        As you mentioned, I’ve submitted an inquiry through your contact form. Once I receive a response from your team, I’ll follow up with the necessary details and additional data as needed.

                                        Thank you for your continued support.

                                        VinnyV Offline
                                        VinnyV Offline
                                        Vinny
                                        ModalAI Team
                                        wrote on last edited by
                                        #33

                                        Hi @Jetson-Nano
                                        I received your data package and will review it this evening.
                                        Thanks!
                                        Vinny

                                        VinnyV 1 Reply Last reply
                                        0
                                        • VinnyV Vinny

                                          Hi @Jetson-Nano
                                          I received your data package and will review it this evening.
                                          Thanks!
                                          Vinny

                                          VinnyV Offline
                                          VinnyV Offline
                                          Vinny
                                          ModalAI Team
                                          wrote on last edited by
                                          #34

                                          Hi @Jetson-Nano I have reviewed your schematic again and your layout files.
                                          I cannot see any reason why your design will not work.
                                          The only suggestion I have is to increase your capacitors here to 1uF:
                                          772656ba-107d-4f9a-9b53-37b133cb8727-image.png

                                          But, otherwise, your layout is OK (some improvements can be made, but nothing is detrimental):

                                          • Pin 1 correct on connector, socket, LDO, other ICs
                                          • Vias are picking up planes correctly
                                          • Voids where expected
                                          • Generous copper trace thickness

                                          The one issue I think I might have found is your reference designators do not match the schematic between the layout. So, I'm wondering if you are installing parts from the BOM in incorrect locations...
                                          For example, the cap on the output of the LDO is "C6" in the layout, but "C7" in your schematic:

                                          0ceb0cb0-3dd8-4b0a-9041-3156136b3acf-image.png
                                          And, your resistors are also not in sync. R1 and R2 in the layout are for the Ic2 expander, but in the SCH, it is for your FLIR module and not R5/R6 as in the SCH:
                                          d134c0be-7357-49a8-9c9e-e17af872904e-image.png
                                          and there are a few other examples. So, I just think perhaps your layout reference designators are not synced to your design.

                                          J1 should be J2, and R3/R4 on the layout does not exist on the SCH.
                                          effa846f-e382-4f07-b89c-f8f118258643-image.png

                                          So, maybe this is where your issue is. I'd recheck the annotation between SCH and Layout, and be sure you are installing all the correct parts in the correct places.

                                          Hope this helped!
                                          Keep us posted.
                                          Thanks!

                                          Jetson NanoJ 1 Reply Last reply
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