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FLIR LEPTON 3.5 Thermal camera with VOXL 2

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  • Jetson NanoJ Jetson Nano

    @Vinny @Alex-Kushleyev
    Thank you for your invaluable feedback on the previous design. I have thoroughly reviewed your input and subsequently updated the schematic to incorporate the suggestions, specifically regarding the integration of an I2C GPIO expander. The updated schematic is attached for your review.

    During recent debugging, I observed a critical issue: the Lepton module is not powering up, and no shutter sound is audible. This suggests a fundamental problem with power delivery or clocking to the module, which is currently preventing any functionality.

    Concurrent to addressing this critical power-up issue, I would appreciate your expert insights on a few points concerning the updated design of the I2C GPIO expander and Lepton module interfacing:

    • 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?

    • 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?

    • 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?

    • 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?

    Your guidance on both the immediate power-up challenge and the schematic queries would be greatly appreciated.

    20fb34b6-34cc-4290-8509-fde084557724-image.png

    Thanks.

    VinnyV Offline
    VinnyV Offline
    Vinny
    ModalAI Team
    wrote on last edited by
    #14

    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 1 Reply Last reply
    0
    • 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
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