On motion control with LEGO Spike

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LEGO Spike Color Sensor (Prime or Essential)

The Spike Color Sensor is often used for tracking markings on the floor in activities like FLL or WRO challenges. It is important to understand, that the sensor has a certain size of a spot that it watches. To determine exact dimensions of the spot I have built a test rig:

Spike Prime Color Sensor Calibrator
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Straightening warped LEGO plates, twisted frames and bent axles

Recently I have purchased a second-hand LEGO set only to find some large, rare (as in: expensive to replace) parts WARPED.

I searched the net and found several threads where people reported on similar issues, but no good solution. So I have put my experience with plastics to work and found an easy fix.

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Fixing LEGO Railroad switches / points

So you flip the LEGO switch on your LEGO Railroad system and… nothing happens. Or the switch moves half-way and stops.

There is a post here: https://bricks.stackexchange.com/questions/11141/lego-track-switch-doesnt-close-properly describing what I was facing recently. I found a better solution than described there and a more permanent fix.

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Posted in LEGO, Powered Up | 4 Comments

Elgato Camlink 4k vs. China “HDMI to USB” converter

A lot was posted all over the internet about capturing HDMI output and whether CamLink is worth its $120 price tag since there are $20 alternatives out there. Trying to decide for myself I googled around and all I found were discussions on image/video quality, like this very informative video from Tech Audit TV:

What this (and similar videos) don’t go into, but what is as important, is what these dongles really do, because that’s where the rub is.


Elgato Camlink 4kChina HDMI to USB dongle
does not do scaling of imagescales image to set size
passes through raw data streamcompresses data stream to MJPEG
PC side needs to process data rate at resolution and fps the camera sends itPC side can request data at lower rate (resolution, fps)
Provides the actual camera fpsProvides own fps, you can select from a list, but for non-standard ones you are at loss
TL; DR version
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