# Knowledge Base **URL:** https://forum.hello-robot.com/c/knowledge-base/13.md?page=1 [Latest](https://forum.hello-robot.com/latest.md) · [Categories](https://forum.hello-robot.com/categories.md) **Page:** 2 --- ## [Practical guide to lift gravity compensation](https://forum.hello-robot.com/t/practical-guide-to-lift-gravity-compensation/657)
**Author:** [@aedsinger](https://forum.hello-robot.com/u/aedsinger)\ **Replies:** 0\ **Last updated:** [April 4, 2023, 7:40pm UTC](https://forum.hello-robot.com/t/practical-guide-to-lift-gravity-compensation/657 "2023-04-04T19:40:26Z")
TLDR: If your lift tends to slowly descend under its own weight, you may need to adjust your gravity compensation Lift gravity compensation for Stretch may be something you didn’t even know existed. In most cases, you w… --- ## [Practical guide to guarded contacts](https://forum.hello-robot.com/t/practical-guide-to-guarded-contacts/654)
**Author:** [@aedsinger](https://forum.hello-robot.com/u/aedsinger)\ **Replies:** 2\ **Last updated:** [April 4, 2023, 1:01am UTC](https://forum.hello-robot.com/t/practical-guide-to-guarded-contacts/654 "2023-04-04T01:01:28Z")
Greetings. A few users have gotten tripped up with Stretch guarded contacts so we thought we’d try to provide some practical guidance here. Simply put: A guarded contact limits the current that the motor in the arm, lif… --- ## [Working productively around Realsense D435i](https://forum.hello-robot.com/t/working-productively-around-realsense-d435i/647)
**Author:** [@Mohamed\_Fazil](https://forum.hello-robot.com/u/Mohamed_Fazil)\ **Replies:** 0\ **Last updated:** [March 23, 2023, 5:59am UTC](https://forum.hello-robot.com/t/working-productively-around-realsense-d435i/647 "2023-03-23T05:59:49Z")
The Realsense D435i is the RGB-D camera found in the Stretch’s head pan-tilt module and it functions as the primary perception sensor for the robot. When the Realsense D435i camera is connected to a Linux computer via US… --- ## [Using the Firmware Trace tool to debug firmware](https://forum.hello-robot.com/t/using-the-firmware-trace-tool-to-debug-firmware/632)
**Author:** [@aedsinger](https://forum.hello-robot.com/u/aedsinger)\ **Replies:** 0\ **Last updated:** [March 10, 2023, 7:30pm UTC](https://forum.hello-robot.com/t/using-the-firmware-trace-tool-to-debug-firmware/632 "2023-03-10T19:30:03Z")
We have introduced a new debugging tool for Stretch Body called Firmware Trace. To use it you will need to update to at least Stretch Factory v0.3.18 Stretch Body v0.4.28 Stepper.v0.3.0p2 Wacc.v0.3.0p2 Pimu.v0.3.0p2 N… --- ## [Using the Stretch Diagnostics tool to debug an issue](https://forum.hello-robot.com/t/using-the-stretch-diagnostics-tool-to-debug-an-issue/633)
**Author:** [@aedsinger](https://forum.hello-robot.com/u/aedsinger)\ **Replies:** 0\ **Last updated:** [March 10, 2023, 9:45pm UTC](https://forum.hello-robot.com/t/using-the-stretch-diagnostics-tool-to-debug-an-issue/633 "2023-03-10T21:45:05Z")
We have introduced a new tool called Stretch Diagnostics to assist when debugging an issue. The tool runs a suite of tests to check for correct device configurations, sensor values, software package versions, etc. It is… --- ## [Running Stretch from a Wireless HDMI Dongle, need one less cable](https://forum.hello-robot.com/t/running-stretch-from-a-wireless-hdmi-dongle-need-one-less-cable/492)
**Author:** [@pgrady3](https://forum.hello-robot.com/u/pgrady3)\ **Replies:** 3\ **Last updated:** [March 4, 2023, 8:57pm UTC](https://forum.hello-robot.com/t/running-stretch-from-a-wireless-hdmi-dongle-need-one-less-cable/492 "2023-03-04T20:57:08Z")
Hi all, we’ve been working with the Stretch RE1 for some mobile manipulation research. Although the Stretch was obviously designed to be untethered, we’ve done most of our work with at least the power cable and HDMI cabl… --- ## [Watchdog on joint velocity](https://forum.hello-robot.com/t/watchdog-on-joint-velocity/619)
**Author:** [@aedsinger](https://forum.hello-robot.com/u/aedsinger)\ **Replies:** 0\ **Last updated:** [March 4, 2023, 12:16am UTC](https://forum.hello-robot.com/t/watchdog-on-joint-velocity/619 "2023-03-04T00:16:37Z")
With Stretch Body 0.4.25 and firmware Stepper.v0.2.7p1 we have introduced a watchdog on the stepper velocity controllers. This was introduced primarily as a safety feature when doing velocity control on the base. This w… --- ## [Integrating custom sensors onto the Stretch wrist](https://forum.hello-robot.com/t/integrating-custom-sensors-onto-the-stretch-wrist/35)
**Author:** [@aedsinger](https://forum.hello-robot.com/u/aedsinger)\ **Replies:** 0\ **Last updated:** [June 25, 2020, 9:09pm UTC](https://forum.hello-robot.com/t/integrating-custom-sensors-onto-the-stretch-wrist/35 "2020-06-25T21:09:58Z")
Hello Stretch users, We’ve recently posted a few new tutorials I wanted to make you aware of: Using the Stretch Wrist Expansion Header These tutorials describe how to integrate custom sensors and other hardware onto y… --- ## [Handling Dynamixel servo overload errors](https://forum.hello-robot.com/t/handling-dynamixel-servo-overload-errors/613)
**Author:** [@aedsinger](https://forum.hello-robot.com/u/aedsinger)\ **Replies:** 0\ **Last updated:** [February 28, 2023, 6:23pm UTC](https://forum.hello-robot.com/t/handling-dynamixel-servo-overload-errors/613 "2023-02-28T18:23:12Z")
It is possible for the Stretch Dynamixel servos to become overloaded or overheated during normal operation. In particular: Stretch Gripper: When grasping an object with a strong grip for a prolonged period Wrist Yaw: W… --- ## [Making videos of Stretch : lenses, lights, editors, and more](https://forum.hello-robot.com/t/making-videos-of-stretch-lenses-lights-editors-and-more/54)
**Author:** [@hello-ck](https://forum.hello-robot.com/u/hello-ck)\ **Replies:** 0\ **Last updated:** [July 31, 2020, 5:15pm UTC](https://forum.hello-robot.com/t/making-videos-of-stretch-lenses-lights-editors-and-more/54 "2020-07-31T17:15:39Z")
Hello everyone, In robotics, videos are an important form of communication. In this post, I describe how we made many of our YouTube videos for our recent public launch. Specifically, this post covers how we shot Stretc… --- ## [Recording video from the Realsense camera](https://forum.hello-robot.com/t/recording-video-from-the-realsense-camera/170)
**Author:** [@jdelpreto](https://forum.hello-robot.com/u/jdelpreto)\ **Replies:** 7\ **Last updated:** [September 3, 2022, 6:30am UTC](https://forum.hello-robot.com/t/recording-video-from-the-realsense-camera/170 "2022-09-03T06:30:24Z")
I may just be missing it in the docs, but is there a simple way to capture video and/or pictures from Stretch’s camera? I don’t need to process or stream anything in real time - just saving them locally while I teleoper… --- ## [Commanding velocity to the arm and lift](https://forum.hello-robot.com/t/commanding-velocity-to-the-arm-and-lift/386)
**Author:** [@sguysc](https://forum.hello-robot.com/u/sguysc)\ **Replies:** 3\ **Last updated:** [March 4, 2022, 8:55pm UTC](https://forum.hello-robot.com/t/commanding-velocity-to-the-arm-and-lift/386 "2022-03-04T20:55:27Z")
Hello, Is there a way to send velocity commands to the joints (i.e. not the base) with the python library or with ROS ? Thank you --- ## [Working with ArUco Markers](https://forum.hello-robot.com/t/working-with-aruco-markers/243)
**Author:** [@kpputhuveetil](https://forum.hello-robot.com/u/kpputhuveetil)\ **Replies:** 2\ **Last updated:** [July 8, 2021, 9:26pm UTC](https://forum.hello-robot.com/t/working-with-aruco-markers/243 "2021-07-08T21:26:42Z")
Hello! I’ve been working with the detect\_aruco\_markers node from stretch\_core in the stretch\_ros repository and have been noticing some discrepancies between the detected position of a given set of Aruco tags and their … --- ## [Playing sound from the ROS Speakers](https://forum.hello-robot.com/t/playing-sound-from-the-ros-speakers/168)
**Author:** [@Robot\_Lover](https://forum.hello-robot.com/u/Robot_Lover)\ **Replies:** 1\ **Last updated:** [May 14, 2021, 7:29pm UTC](https://forum.hello-robot.com/t/playing-sound-from-the-ros-speakers/168 "2021-05-14T19:29:50Z")
I am wondering if there is any way to use ROS in the stretch-robot to take in text or an audio file as input and play it through the speakers as output. Is there anything prewritten or any packages that can be used with … --- ## [Forward and inverse kinematic model](https://forum.hello-robot.com/t/forward-and-inverse-kinematic-model/154)
**Author:** [@jiawei\_li](https://forum.hello-robot.com/u/jiawei_li)\ **Replies:** 3\ **Last updated:** [May 4, 2021, 1:42am UTC](https://forum.hello-robot.com/t/forward-and-inverse-kinematic-model/154 "2021-05-04T01:42:52Z")
Hello! Does stretch provide the official forward kinematic formula, like Jacobian matrix? [Previous page](https://forum.hello-robot.com/c/knowledge-base/13.md)