Skip to main content

PF IR Receiver as Wireless Touch Sensor

By

Here are the details on the trick that I used in my Battle Tank project to get the NXT to read sensor input from the Power Functions remote control. See the "Method 1". This allows the NXT to see the IR receiver as a single touch sensor, which is actually quite easy to do if you have the two wires needed (PF Extension Wire and RCX Conversion Cable). The "Method 2" was an earlier and much more complex way to get full control from both levers (9 states).

You only get one touch sensor out of this, but with a little timing trick in the NXT program, I made the single PF lever control two NXT-triggered functions on the Battle Tank. A quick press and release of one lever triggers the scissor stabber with one NXT motor, and a press and hold of the same lever triggers the dart gun with another NXT motor. This leaves the other lever on the same channel open to run a PF M-motor in both directions to implement the unfolding saw blade (same M-motor folds/unfolds via a worm gear while also spinning the blade by up-gearing). Then the other IR receiver is attached to the two PF XL-motors to do the driving on another channel.

It looks like you could extend this trick to get two touch sensors by connecting the other half of the IR receiver to a second sensor port on the NXT, but this doesn't work. Pressing either lever ends up triggering both touch sensors. Wondering what was going on here, I consulted Philo, who kindly explained that the whole setup is electrically questionable to begin with because the PF and NXT sides don't share a common ground, but it ends up working and being safe with one sensor, but attaching two creates a strange current flow and also results in a short circuit condition if the levers are pushed in opposite directions. So don't bother trying that...
Labels:

Popular posts from this blog

ROBOTMAK3RS Review: LEGO River Steamboat

By Asha Seshan - ROBOTMAK3R
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...
Read more

Celebrating 25 Years of MINDSTORMS

By Asha Seshan - ROBOTMAK3R
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...
Read more

Ghostbusters R.T.V Remix

By Asha Seshan - ROBOTMAK3R
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...
Read more