# Homing lift downward contact calibration?

**URL:** <https://forum.hello-robot.com/t/homing-lift-downward-contact-calibration/214>\
**Category:** Ask\
**Created:** [June 20, 2021, 6:43pm UTC](https://forum.hello-robot.com/t/homing-lift-downward-contact-calibration/214 "2021-06-20T18:43:49Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![smth](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.hello-robot.com/smth/32/94_2.png) [@smth](https://forum.hello-robot.com/u/smth)\
**Post date:** [June 20, 2021, 6:43pm UTC](https://forum.hello-robot.com/t/homing-lift-downward-contact-calibration/214/1 "2021-06-20T18:43:50Z")

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I noticed that the lift does not ever self-calibrate how low it can go, but it does calibrate how high the lift can go (and it marks those positions).

Are the downward limits hard-coded?

I am just curious about this, it isn’t blocking any work.

Separately, I am curious as to where files like `stretch_xbox_controller_teleop.py` are on github, because I couldn’t find them.

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<div class="post-metadata">

**Author:** ![aedsinger](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.hello-robot.com/aedsinger/32/6_2.png) [@aedsinger](https://forum.hello-robot.com/u/aedsinger)\
**Post date:** [June 20, 2021, 11:09pm UTC](https://forum.hello-robot.com/t/homing-lift-downward-contact-calibration/214/2 "2021-06-20T23:09:34Z")

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Hi. Indeed, the lift range of motion was calibrated at the factory. Nominal range is 1.1m.

This value can be found in your factory params (~/stretch\_user/stretch-re1-xxx/stretch\_re1\_factory\_params.py). For example:

```auto
lift:
  range_m:
  - 0.0
  - 1.0981830239156594

```

We don’t measure in the downward direction for two reasons:

- To avoid inadvertent collisions if the user has an unknown payload attached to the wrist.
- To decrease the time required to run the homing procedure

Also, `stretch_xbox_controller_teleop.py` is a part of the hello-robot-stretch-body-tools package, which is found here:

> **[hello-robot/stretch\_body](https://github.com/hello-robot/stretch_body/tree/master/tools/bin)**
>
> master/tools/bin