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

Celebrating MINDSTORMS with a Remix - Part 2

The ROBOTMAK3RS continued their celebration of the 25th Anniversary of MINDSTORMS through these summer and fall remix projects. Each ROBOTMAK3R was tasked with selecting one LEGO set of their choice and combining it with a MINDSTORMS set. Below are the five amazing models they came up with. Remote controlled material handle r by Jozua van Ravenhorst (aka Mr Jo) This remix combines the LEGO Technic Material Handler (42144) with MINDSTORMS EV3 (31313) It uses the power of pneumatic cylinders to move objects around. By using a bluetooth remote control, very precise movements can be made with this model. Touch sensors in the base chassis prevent the turret twisting the cables that go through the turntable to much. The program has several protections to prevent over pressurizing the system for each of the 3 individual pumps and valves that control the 2 booms and claws. The real version of this machine is mostly used in waste material sites to bring the material to machines that sort and

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

MINDSTORMS Retires!

2023 is the 25th Anniversary of the MINDSTORMS brand. For 25 years, MINDSTORMS has educated and inspired a generation of robot builders, both children and adults. Unfortunately, the LEGO Group decided to end the line on December 2022. Many ROBOTMAK3RS have been passionately involved with the development of MINDSTORMS through the MUP and MCP programs. Even with the newest Robot Inventor line, several ROBOTMAK3RS were invited to submit additional bonus models that were included in the official app. Regardless of the retirement of a major LEGO robotics product line, ROBOTMAK3RS continue to MAKE-SHARE-INSPIRE using all LEGO robotics platforms available to us. Here is the official statement from LEGO. Since its launch in September 1998, LEGO MINDSTORMS has been one of the core ‘Build & Code’ experiences in the company’s portfolio, carrying with it significant brand equity and becoming a stand-out experience for the early days of consumer robotics and leading to current Build & Code