Skip to main content

Analog Multiplexer for NXT touch sensor by STAAK


STAAK posted on the Polish LUGPOL forum an nice instruction guide in How to build a touch sensor multiplexer.




He describes:" For both multiplexers I used resistors with values 32k, 10k, 68k, and 150k. The NXT touch sensor already have a built-in additional 2.2 k resistor.

By design, the two multiplexers (RCX, NXT) will work with the NXT via a single block in NXT-G. Because the use of the internal resistors (and the same precision resistors), I needed to create a block for the NXT-G that allows the thresholds to be set by the user. Normally when you insert a block to the project can be seen only as the left side of the settings. Select the checkbox will show a window for manually setting the appropriate thresholds.

Block Parameters:
Port: 1 to 4 = the Port connected on the NXT
Limit: 1 to 6
TH1000 for threshold limit of 5 = 520 indicates that this threshold is detected in the range 515 < TH1000 < 525.
Threshold: 0 to 1023

Drop-down box in the left window is used only for viewing a given threshold value.
A threshold value is nothing more than the raw value for the relevant states of the configuration of sensors

TH1011 should be read as TH Sensor1=1 Sensor2=0 Sensor3=1 Sensor4=1 where
Sensor1 = in series with 10k resistor
Sensor2 = in series with 32k resistor
Sensor3 = in series with 68k resistor
Sensor4 = in series with 150k resistor

The output signal from this block is the four outputs (T1-T4), True / False
where True state of the output indicates that the sensor is pressed.

After setting the threshold check block, save the project.
The Copy/Paste option allows you to insert the block into a new project together with the pre-set thresholds.

Click here to download the block.




The cost of the multiplexer elements was less than 2$ for the resistors
The NXT-G block was written in LabView with the overlay LabVIEW Toolkit for LEGO MINDSTORMS NXT available on the National Instruments.

see also his Brickshelf folder.

Well done STAAK!

Popular posts from this blog

ROBOTMAK3RS Review: LEGO River Steamboat

I thought the LEGO River Steamboat would be an interesting set for a ROBOTMAK3R review for a few reasons. First, the LEGO designer of the model is Marina Stampoli, a long-time collaborator of the late ROBOTMAK3R Vassilis Chryssanthakopoulo s. From earlier collaborations with Vassilis, I  knew Marina was incredibly talented, with an eye for aesthetics and functionality. Her background in architecture is particularly useful for her relatively new position at LEGO. Her other sets include the Magic of Disney (21352), Message Board (41839), and Red London Telephone Box (21347). Second, watching Marina's reveal video  and reading her designer interview made this set even more tempting to build. The gearing mechanisms running through the model gave way to many opportunities for automation using LEGO robotics elements. Since ROBOTMAK3RS is all about adding interactivity and automation to LEGO brick, I thought it would be fun to see where and how LEGO robotics could be added to this s...

Celebrating 25 Years of MINDSTORMS

In celebration of the 25th Anniversary of MINDSTORMS, we take a trip through history. Please also visit ROBOTMAK3RS Community every week as we highlight different projects all through 2023 in celebration of the anniversary. Some of the early history is based on the content shared by  Coder Shah  in our  MINDSTORMS EV3 Community Group . Some of the text and links may have been edited from his original posts for consistency and clarity.  1984 - Kjeld Kirk Kristiansen watched a TV program called "Talking Turtle," where MIT professor Seymour Papert demonstrated how children could control robot "turtles" using LOGO, a programming language he developed. 1988 - The collaboration between MIT and LEGO resulted in LEGO TC Logo in 1988, which allowed students to control LEGO models using computer commands. The video shows Papert demonstrating TC Logo. 1990 - LEGO TC Logo was hampered since the robots you built had to be tethered to a personal computer. LEGO and MIT...

Ghostbusters R.T.V Remix

Nino Guba is from Torrance, California, USA. He played with LEGO as a kid, but growing up in the Philippines, it wasn’t something he had easy access to. He only got reintroduced to LEGO when he moved to the US and had kids of his own. When his sons were younger, they received LEGO sets as gifts, but as they grew older, the sets got put into storage as their interest faded. Fast forward a few years, he started coming up with his own product ideas and thought about how he could quickly prototype them. That’s when he discovered LEGO MINDSTORMS—and was hooked! He raided his kids’ old collection, got everything organized, and now he's designing and building his own creations, blending his coding skills with LEGO robotics to bring ideas to life. Tell us about your Ghostbusters Remote Trap Vehicle (R.T.V) project. This project is a LEGO Technic adaptation of the Ghostbusters R.T.V.—a ghost trap converted into a remote-controlled vehicle. Its companion build is a prop replica of the Futaba...