VOXL ESC FPV 4-in-1 with Built-in Power Module (MDK-M0138) Issues
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Hello.
I am using the VOXL2 with the FPV ESC and experiencing some issues. I can detect/scan and spin the motors at different rpms using the CLI tool on the voxl, but I cannot get the motors to throttle up in response to my RC transmitter. I verified that my rc throttle channel and actuator outputs are increasing as I raise throttle in mavlink inspector. I also tried calibrating the escs as well but that did not fix the issue. I also checked the VOXL ESC params such as min and max rpm (3000 - 30000 rpm). The motors are emax 2807 1300kvs.
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What software versions are you using? Can you please create a PX4 log and share that via https://logs.px4.io/? Since logging normally doesn't start until you arm the drone you can force the logger to start and stop. For example, from the adb shell you can use px4-logger on to start a log and then px4-logger off to stop the log. Can you also paste the outputs from the detect / scan? Also review this other post: https://forum.modalai.com/topic/4833/throttle-doesnt-work/7
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What software versions are you using? Can you please create a PX4 log and share that via https://logs.px4.io/? Since logging normally doesn't start until you arm the drone you can force the logger to start and stop. For example, from the adb shell you can use px4-logger on to start a log and then px4-logger off to stop the log. Can you also paste the outputs from the detect / scan? Also review this other post: https://forum.modalai.com/topic/4833/throttle-doesnt-work/7
@Eric-Katzfey Attached below. I misspoke, it appears detect fails.
Here is the link: PX4 Logs
voxl2-test-fixture (TF-M0054):/$ voxl-version ──────────────────────────────────────────────────────────────────────────────── system-image: 1.8.06-M0054-14.1a-perf kernel: #1 SMP PREEMPT Wed Oct 22 04:13:18 UTC 2025 4.19.125 ──────────────────────────────────────────────────────────────────────────────── hw platform: M0054 mach.var: 1.0.1 SKU: TF-M0054-4-V1-C11 ──────────────────────────────────────────────────────────────────────────────── voxl-suite: 1.6.3 ──────────────────────────────────────────────────────────────────────────────── Packages: Repo: http://voxl-packages.modalai.com/ ./dists/qrb5165/sdk-1.6/binary-arm64/ Last Updated: 2026-08-06 19:57:23 List: libfc-sensor 1.0.9 libmodal-cv 0.6.0 libmodal-exposure 0.1.4 libmodal-flow 1.0.3 libmodal-journal 0.2.7 libmodal-json 0.4.8 libmodal-pipe 2.14.11 libqrb5165-io 0.6.3 libvoxl-cci-direct 0.3.3 libvoxl-codec 0.0.2 libvoxl-cutils 0.1.6 modalai-slpi 1.2.2 mv-voxl 0.1-r0 qrb5165-bind 0.1-r0 qrb5165-dfs-server 0.2.0 qrb5165-mini-tof-server 0.2.2 qrb5165-rangefinder-server 0.1.6 qrb5165-slpi-test-sig 01-r0 qrb5165-tflite 2.17.2 voxl-bind-spektrum 0.1.1 voxl-camera-calibration 0.6.1 voxl-camera-server 2.2.19 voxl-ceres-solver 2:2.0.0-2 voxl-configurator 1.1.5 voxl-cpu-monitor 0.7.7 voxl-docker-support 1.3.1 voxl-elrs 1.1.0 voxl-esc 1.6.3 voxl-esptool 0.2.0 voxl-feature-tracker 0.5.2 voxl-flow-server 0.3.6 voxl-gphoto2-server 0.0.10 voxl-imu-server 2.0.1 voxl-io-server 0.0.8 voxl-jpeg-turbo 2.1.3-7 voxl-lepton-server 1.3.3 voxl-lepton-tracker 0.0.4 voxl-libgeographic 1.0.0 voxl-libgphoto2 0.0.4 voxl-libuvc 1.0.7 voxl-logger 0.6.1 voxl-mavcam-manager 0.6.0 voxl-mavlink 0.1.6 voxl-mavlink-server 1.4.14 voxl-modem 1.2.3 voxl-mongoose 7.19.0 voxl-mpa-to-ros 0.3.9 voxl-mpa-tools 1.5.6 voxl-nano-tracker 0.1.7 voxl-open-vins-server 0.6.0 voxl-opencv 4.5.5-3 voxl-osd 0.3.8 voxl-portal 0.8.7 voxl-px4 1.14.0-2.0.133 voxl-px4-params 0.9.0 voxl-qvio-server 1.2.3 voxl-remote-id 0.0.9 voxl-reset-slpi 0.0.1 voxl-state-estimator 0.0.6 voxl-streamer 0.8.0 voxl-suite 1.6.3 voxl-tag-detector 0.1.0 voxl-tflite-server 0.5.1 voxl-utils 2.0.2 voxl-uvc-server 0.1.7 voxl-vision-hub 1.9.21 voxl-vtx 2.0.2 voxl-wavemux 0.0.3 voxl2-io 0.0.3 voxl2-security-hardening-utls 1.0-r0 voxl2-system-image 1.8.06-r0 voxl2-wlan 1.0-r0 ────────────────────────────────────────────────────────────────────────────────voxl2-test-fixture (TF-M0054):/$ voxl-esc scan enabling bridge detected voxl-px4 is enabled Removed /etc/systemd/system/multi-user.target.wants/voxl-px4.service. detected voxl-px4 is running, stopping it now Sending kill slpi command! bridge enabled Detected Python version : 3.6.9 (default, May 22 2025, 20:54:22) [GCC 8.4.0] Found voxl-esc tools bin version: 1.10 VOXL Platform: QRB5165 INFO: Scanning for ESC firmware: /dev/slpi-uart-2, baud: 2000000 Sending library name request: libslpi_qrb5165_io.so Sending initialization request INFO: ESC(s) detected on port: /dev/slpi-uart-2, baud rate: 2000000, protocol: firmware INFO: ESC Information: INFO: --------------------- ID : 0 Board : version 42: ModalAi 4-in-1 ESC (M0138-1) UID : 0x203837304848570400440022 Firmware : version 39.25, hash a58f5f6f Bootloader : version 187, hash aad89d63 ID : 1 Board : version 42: ModalAi 4-in-1 ESC (M0138-1) UID : 0x203837304848570300310055 Firmware : version 39.25, hash a58f5f6f Bootloader : version 187, hash aad89d63 ID : 2 Board : version 42: ModalAi 4-in-1 ESC (M0138-1) UID : 0x2038373048485705003A003F Firmware : version 39.25, hash a58f5f6f Bootloader : version 187, hash aad89d63 ID : 3 Board : version 42: ModalAi 4-in-1 ESC (M0138-1) UID : 0x203837304848570400440025 Firmware : version 39.25, hash a58f5f6f Bootloader : version 187, hash aad89d63 --------------------- successfully pinged ESCs disabling bridge Sending kill slpi command! re-enabling voxl-px4 Created symlink /etc/systemd/system/multi-user.target.wants/voxl-px4.service → /etc/systemd/system/voxl-px4.service. restarting voxl-px4 bridge disabled voxl2-test-fixture (TF-M0054):/$ voxl-esc detect enabling bridge detected voxl-px4 is enabled Removed /etc/systemd/system/multi-user.target.wants/voxl-px4.service. detected voxl-px4 is running, stopping it now Sending kill slpi command! bridge enabled Received standard error event SNS_STD_ERROR_NOT_SUPPORTED Couldn't configure flight_controller sensor ERROR: fc_sensor_initialize failed ERROR: Failed to initialize slpi ERROR: Encountered error while initializing bus 12 [ERROR] No ESCs detected disabling bridge Sending kill slpi command! re-enabling voxl-px4 Created symlink /etc/systemd/system/multi-user.target.wants/voxl-px4.service → /etc/systemd/system/voxl-px4.service. restarting voxl-px4 bridge disabled EXITING VOXL-ESC WITH ERROR voxl2-test-fixture (TF-M0054):/$ -
@jbiscan21 , have you tried the actuator test feature in QGC? make sure to remove propellers for safety.
Also, as px4 starts up, the
voxl-escpx4 driver will detect the ESCs and print some information, similar to what the CLI tool does without PX4. You can run voxl-px4 in foreground and check.voxl-px4 -dAlex
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example of
voxl-px4driver output when runningvoxl-px4 -d:... Starting VOXL ESC driver INFO [qshell] Send cmd: 'voxl_esc start' INFO [muorb] [uORB] Marking DeviceNode(qshell_req) as advertised in process_remote_topic INFO [muorb] [qshell] qshell gotten: voxl_esc start INFO [muorb] [qshell] arg0 = 'voxl_esc' INFO [muorb] [qshell] arg1 = 'start' INFO [uORB] Advertising remote topic actuator_outputs INFO [muorb] [voxl_esc] Starting VOXL ESC driver INFO [muorb] [voxl_esc] Params: VOXL_ESC_CONFIG: 1 INFO [muorb] [voxl_esc] Params: VOXL_ESC_MODE: 0 INFO [muorb] [voxl_esc] Params: VOXL_ESC_BAUD: 2000000 INFO [muorb] [voxl_esc] Params: VOXL_ESC_FUNC1: 102 INFO [muorb] [voxl_esc] Params: VOXL_ESC_FUNC2: 103 INFO [muorb] [voxl_esc] Params: VOXL_ESC_FUNC3: 101 INFO [muorb] [voxl_esc] Params: VOXL_ESC_FUNC4: 104 INFO [muorb] [voxl_esc] Params: VOXL_ESC_SDIR1: 0 INFO [muorb] [voxl_esc] Params: VOXL_ESC_SDIR2: 0 INFO [muorb] [voxl_esc] Params: VOXL_ESC_SDIR3: 0 INFO [muorb] [voxl_esc] Params: VOXL_ESC_SDIR4: 0 INFO [muorb] [voxl_esc] Params: VOXL_ESC_PWR_MIN: 0.050000 INFO [muorb] [voxl_esc] Params: VOXL_ESC_RPM_MIN: 2000 INFO [muorb] [voxl_esc] Params: VOXL_ESC_RPM_MAX: 12000 INFO [muorb] [voxl_esc] Params: VOXL_ESC_T_PERC: 90 INFO [muorb] [voxl_esc] Params: VOXL_ESC_T_DEAD: 20 INFO [muorb] [voxl_esc] Params: VOXL_ESC_T_EXPO: 35 INFO [muorb] [voxl_esc] Params: VOXL_ESC_T_MINF: 0.150000 INFO [muorb] [voxl_esc] Params: VOXL_ESC_T_COSP: 0.990000 INFO [muorb] [voxl_esc] Params: VOXL_ESC_VLOG: 1 INFO [muorb] [voxl_esc] Params: VOXL_ESC_PUB_BST: 1 INFO [muorb] [voxl_esc] Params: VOXL_ESC_T_WARN: 0 INFO [muorb] [voxl_esc] Params: VOXL_ESC_T_OVER: 0 INFO [muorb] [voxl_esc] Params: GPIO_CTL_CH: 0 INFO [muorb] [voxl_esc] Params: VOXL_ESC_CMD: 0 INFO [muorb] [qshell] Ok executing command: voxl_esc start INFO [muorb] [voxl_esc] Opening UART ESC device 2, baud rate 2000000 INFO [muorb] [voxl_esc] Successfully opened UART ESC device INFO [muorb] [voxl_esc] Detecting ESCs... INFO [muorb] [voxl_esc] ESC ID : 0 INFO [muorb] [voxl_esc] Board Type : 40: ModalAi 4-in-1 ESC (M0129-3) INFO [muorb] [voxl_esc] Unique ID : 0x2039333557555313000F0036 INFO [muorb] [voxl_esc] Firmware : version 39, hash 9c6233d6 INFO [muorb] [voxl_esc] Bootloader : version 184, hash 10bf24c8 INFO [muorb] [voxl_esc] Reply time : 735us INFO [muorb] [voxl_esc] VOXL_ESC: INFO [muorb] [voxl_esc] ESC ID : 1 INFO [muorb] [voxl_esc] Board Type : 40: ModalAi 4-in-1 ESC (M0129-3) INFO [muorb] [voxl_esc] Unique ID : 0x2039333557555313000F0032 INFO [muorb] [voxl_esc] Firmware : version 39, hash 9c6233d6 INFO [muorb] [voxl_esc] Bootloader : version 184, hash 10bf24c8 INFO [muorb] [voxl_esc] Reply time : 721us INFO [muorb] [voxl_esc] VOXL_ESC: INFO [muorb] [voxl_esc] ESC ID : 2 INFO [muorb] [voxl_esc] Board Type : 40: ModalAi 4-in-1 ESC (M0129-3) INFO [muorb] [voxl_esc] Unique ID : 0x2039333557555313000F0034 INFO [muorb] [voxl_esc] Firmware : version 39, hash 9c6233d6 INFO [muorb] [voxl_esc] Bootloader : version 184, hash 10bf24c8 INFO [muorb] [voxl_esc] Reply time : 104us INFO [muorb] [voxl_esc] VOXL_ESC: INFO [muorb] [voxl_esc] ESC ID : 3 INFO [muorb] [voxl_esc] Board Type : 40: ModalAi 4-in-1 ESC (M0129-3) INFO [muorb] [voxl_esc] Unique ID : 0x2039333557555313000F0038 INFO [muorb] [voxl_esc] Firmware : version 39, hash 9c6233d6 INFO [muorb] [voxl_esc] Bootloader : version 184, hash 10bf24c8 INFO [muorb] [voxl_esc] Reply time : 727us INFO [muorb] [voxl_esc] VOXL_ESC: INFO [muorb] [voxl_esc] Use extended rpm packet : 1 INFO [muorb] [voxl_esc] All ESCs successfully detected ... -
@jbiscan21 , have you tried the actuator test feature in QGC? make sure to remove propellers for safety.
Also, as px4 starts up, the
voxl-escpx4 driver will detect the ESCs and print some information, similar to what the CLI tool does without PX4. You can run voxl-px4 in foreground and check.voxl-px4 -dAlex
Hello, using the actuator sliders in QGC results in the same behavior. The motors just spin at the same constant (arming) speed. Here are the results of
voxl-px4 -dStarting VOXL ESC driver INFO [qshell] Send cmd: 'voxl_esc start' INFO [muorb] [uORB] Marking DeviceNode(qshell_req) as advertised in process_remote_topic INFO [muorb] [qshell] qshell gotten: voxl_esc start INFO [muorb] [qshell] arg0 = 'voxl_esc' INFO [muorb] [qshell] arg1 = 'start' INFO [uORB] Advertising remote topic actuator_outputs INFO [muorb] [voxl_esc] Starting VOXL ESC driver INFO [muorb] [voxl_esc] Params: VOXL_ESC_CONFIG: 1 INFO [muorb] [voxl_esc] Params: VOXL_ESC_MODE: 0 INFO [muorb] [voxl_esc] Params: VOXL_ESC_BAUD: 2000000 INFO [muorb] [voxl_esc] Params: VOXL_ESC_FUNC1: 101 INFO [muorb] [voxl_esc] Params: VOXL_ESC_FUNC2: 104 INFO [muorb] [voxl_esc] Params: VOXL_ESC_FUNC3: 102 INFO [muorb] [voxl_esc] Params: VOXL_ESC_FUNC4: 103 INFO [muorb] [voxl_esc] Params: VOXL_ESC_SDIR1: 0 INFO [muorb] [voxl_esc] Params: VOXL_ESC_SDIR2: 0 INFO [muorb] [voxl_esc] Params: VOXL_ESC_SDIR3: 0 INFO [muorb] [voxl_esc] Params: VOXL_ESC_SDIR4: 0 INFO [muorb] [voxl_esc] Params: VOXL_ESC_PWR_MIN: 0.050000 INFO [muorb] [voxl_esc] Params: VOXL_ESC_RPM_MIN: 3000 INFO [muorb] [voxl_esc] Params: VOXL_ESC_RPM_MAX: 30653 INFO [muorb] [voxl_esc] Params: VOXL_ESC_T_PERC: 90 INFO [muorb] [voxl_esc] Params: VOXL_ESC_T_DEAD: 20 INFO [muorb] [voxl_esc] Params: VOXL_ESC_T_EXPO: 35 INFO [muorb] [voxl_esc] Params: VOXL_ESC_T_MINF: 0.150000 INFO [muorb] [voxl_esc] Params: VOXL_ESC_T_COSP: 0.990000 INFO [muorb] [voxl_esc] Params: VOXL_ESC_VLOG: 1 INFO [muorb] [voxl_esc] Params: VOXL_ESC_PUB_BST: 1 INFO [muorb] [voxl_esc] Params: VOXL_ESC_T_WARN: 0 INFO [muorb] [voxl_esc] Params: VOXL_ESC_T_OVER: 0 INFO [muorb] [voxl_esc] Params: GPIO_CTL_CH: 0 INFO [muorb] [voxl_esc] Params: VOXL_ESC_CMD: 0 INFO [muorb] [qshell] Ok executing command: voxl_esc start INFO [muorb] [voxl_esc] Opening UART ESC device 2, baud rate 2000000 INFO [muorb] [voxl_esc] Successfully opened UART ESC device INFO [muorb] [voxl_esc] Detecting ESCs... INFO [muorb] [voxl_esc] ESC ID : 0 INFO [muorb] [voxl_esc] Board Type : 42: ModalAi 4-in-1 ESC (M0138-1) INFO [qshell] qshell return value timestamp: 299177998, local time: 299182990 INFO [muorb] [voxl_esc] Unique ID : 0x203837304848570400440022 INFO [muorb] [voxl_esc] Firmware : version 39, hash a58f5f6f INFO [muorb] [voxl_esc] Bootloader : version 187, hash aad89d63 INFO [muorb] [voxl_esc] Reply time : 709us INFO [muorb] [voxl_esc] VOXL_ESC: INFO [muorb] [voxl_esc] ESC ID : 1 INFO [muorb] [voxl_esc] Board Type : 42: ModalAi 4-in-1 ESC (M0138-1) INFO [muorb] [voxl_esc] Unique ID : 0x203837304848570300310055 INFO [muorb] [voxl_esc] Firmware : version 39, hash a58f5f6f INFO [muorb] [voxl_esc] Bootloader : version 187, hash aad89d63 INFO [muorb] [voxl_esc] Reply time : 724us INFO [muorb] [voxl_esc] VOXL_ESC: INFO [muorb] [voxl_esc] ESC ID : 2 Starting CRSF RC driver INFO [muorb] [voxl_esc] Board Type : 42: ModalAi 4-in-1 ESC (M0138-1) INFO [muorb] [voxl_esc] Unique ID : 0x2038373048485705003A003F INFO [muorb] [voxl_esc] Firmware : version 39, hash a58f5f6f INFO [muorb] [voxl_esc] Bootloader : version 187, hash aad89d63 INFO [muorb] [voxl_esc] Reply time : 716us INFO [muorb] [voxl_esc] VOXL_ESC: INFO [muorb] [voxl_esc] ESC ID : 3 INFO [muorb] [voxl_esc] Board Type : 42: ModalAi 4-in-1 ESC (M0138-1) INFO [muorb] [voxl_esc] Unique ID : 0x203837304848570400440025 INFO [muorb] [voxl_esc] Firmware : version 39, hash a58f5f6f INFO [muorb] [voxl_esc] Bootloader : version 187, hash aad89d63 INFO [muorb] [voxl_esc] Reply time : 706us INFO [muorb] [voxl_esc] VOXL_ESC: INFO [muorb] [voxl_esc] Use extended rpm packet : 1 INFO [muorb] [voxl_esc] All ESCs successfully detected INFO [uORB] Advertising remote topic actuator_outputs_debug INFO [uORB] Advertising remote topic esc_status -
@alex-kushleyev @eric-katzfey
One thing I noticed, if I changeESC Command Typefrom RPM to PWM in the actuators tab, then I can increase the motor speeds -
@jbiscan21 , can you also share the esc params that you uploaded to the ESC after ESC calibration ? I am assuming you went through this procedure : https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-tools/calibration.md
From the log I see that all 4 motors spun up but the rpm is capped at about 2200 rpm, which may mean you ESC tuning params are incorrect.
Also note that after arming, your drone immediately commands about 10000 rpm, which is not great, because that would be a sudden jump.. you may want to check your flight mode to avoid this.
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