Determining sound direction

I've been playing a bit more with datalogging (check out the fantastic tips from Brian in the forums) and I've always wanted a robot that could come to me when I called it. The sound sensor is great for 'detecting' sound but no good for deciding where the sound came from. One way to figure out where the sound is coming from is to use 2 sound sensors.

So I built myself a little NXT head that had 2 sound sensors and a bit of foam in between.

"Sure it's pretty" I hear you say, but whats that foam in between the ears for?

Well I figure that if I had 2 ears, with some sort of dampening material in between, the ears would hear the same sound source, but at different volume levels.

ie. If I clapped my hands very loudly on the left hand side, then the left 'ear' would hear a certain volume and the right 'ear' would also register a sound, but at a much quieter level.

So I set up my head and start writing sound readings from both the left and right ears to a text file as fast as I can. I'm not too concerned with the sampling rate, as I'm more interested in the difference in sound levels for the same 'clap'

I take the results and put them through Excel where I subtract the value of the right ear from the value of the left ear to give me a difference.

Now if the clap happens directly in front (or behind) my NXT head, then the sound levels will be the same and the difference will be 0. But if I clap off to the left hand side, then the left reading will be higher than the right reading and my difference will be a positive number. If I clap on the right hand side then I'll get a negative number.

This graph shows the difference between the left and right ears with 3 test claps, once on the left, once in the center and once on the right.

From this I can see anything under -40 is a definite clap on the left and anything over +40 is a clap on the right.

So now I can write a program that takes the two sound sensor readings and subtracts one from the other. If the result is more negative than -40, I turn clockwise a small amount. If it is greater than 40, I mover counter-clockwise for a small amount.

I think with more sound dampening, I could probably get it to respond a little more accurately.

--
Damien Kee

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

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

Celebrating MINDSTORMS with a Remix Part 1

In honor of the 25th Anniversary of MINDSTORMS, we asked ROBOTMAK3RS to combine a LEGO set of their choice with a MINDSTORMS set. Here is what these five ROBOTMAK3RS came up with. MINDSTORMS Chess Assistant by Arvind Seshan Overview: When you are new to chess, it can be a challenge to remember which pieces go where. Now, you can use machine learning and LEGO MINDSTORMS Robot Inventor to build a tool to help you learn where all the chess pieces go on the chess board. Sets used: LEGO® Iconic Chess Set (40174) and MINDSTORMS Robot Inventor (51515) Review: I really like how the chess set base can store all the pieces underneath and that the board neatly splits in half for handy storage. The chess pieces themselves are very sturdy and well built. My only criticism is the building of the box itself. It was quite difficult to see what pieces to use and since the entire box is made mostly of thin plates, it took a lot of time and patience. I would have liked the storage area to be sliding dra

ROBOTMAK3RS Blog

Search This Blog