About sound beacon question

In recent public numbers, many students in the study of sound beacon localization problem, sent a number of questions.

Question 1

Zhuo greatly this method can measure the distance but the angular orientation of the sound source determination how should it?

Reply:
There are two ways:

1. Double, or a plurality of microphones aligned, the orientation of the sound source is determined based on these received by the microphone to the audio delay;
2. With the movement of car models, according to the car model itself, the sound source position and the movement distance measured to calculate the direction of the sound source.

声音信标的底座造型

When this determination based on the distance between the microphone and the sound source localization program. The accuracy of the distance between the microphone and the two related?
Increasing the number of microphones can improve the accuracy of it? (I think the increase in the number of microphones in accordance with this principle has not improved much, right?),
Zhuo is how much you think?

Reply:

1. Whether improvements have relationships with major sources of error;
2. If the primary source of error is noise in the signal processing, the increase in the number of microphones and the distance between the two microphones can be improved;
3. If the error from the acoustic wave reflection brought increased, bypass the like, can only be improved by increasing the orientation of the sound source microphone distance is determined.

Zhuo much research for a long time or did not understand, calculate the maximum delay p1, p2 refers to what? Suitable this is to make the whole 2500 points and 2500 points collected emitted correlation operation, or at the same time, to make correlation calculation section acquired data and then find the difference between the chirp and the maximum value corresponding to the current time point and calculates a delay ? Did it not been synchronized to make and receive job thing?

Re:
Your question be asked to the point. An important condition experiments in tweets: voice and sound are accepted by the same single-chip control. This is equivalent to sending and receiving are synchronized! ! ! ! This, in practice, to accept the microcontroller can send and car models how sound synchronization beacon it? Later I wrote a tweet to explain it. (In fact, see the following reply to the question)

声音信标的底座选型

Question 2

After Zhuo teacher Hello, on mutual correlation operation, I can understand two conventional waveform computation, the time difference between the two waveforms corresponding to the maximum value. But the specific sound ranging How is it? I do not quite understand.

For example, the transmit and receive fully independent, continuous transmission signal is sent, the receiver is turned on at any time, this time how to do cross-correlation operation it?

For two input sound related distance calculation, we know the waveform of a transmitting side, the other one is received waveform. But the received waveform should take that part of the operation to do it?

Zhuo hopes the students were puzzled teacher have time to answer very grateful, I wish Zhuo much health.

Reply:

1. Push experiments described herein is the subject of the speaker sound signal, and a receiving unit to verify the accuracy of the measurement. Therefore the experiment, a signal is generated by the acoustic wave generated by the microcontroller after the audio amplifier via a cable drive beacon speaker; and sound signal received by the microphone at the same time collecting the microcontroller. Experiment received correlation signal is a signal related to the operation of the signal emitted.
2. Since the signal emitted by the memory itself is generated after DA conversion in the Chirp waveform data memory, it does not require acquisition, waveform data memory directly on it.
3. In the future, the actual beacon in the game, the sound is emitted by the beacon, and the sound is detected by the intelligent microcontroller to collect the car. So, single-chip car models is how we can get the time and the signal waveform signals it? In actual game beacon system, while also providing a radio frequency modulated (FM) signal in the field, and the beacon light receiving module to obtain car models are FM Chirp signal by sound. Since the radio signal propagation speed is the speed of light, it can be considered a beacon and receiving the audio module car models obtained by simultaneous FM, and the waveform is the same.
4. Specific FM modules can be pushed to accept the text content "monolithic piece pick receiver" in the production according to January 31.

RDA5807单片调频收音机接受模块

5. Of course, the car models may be mounted on a plurality of sound sensors to determine the position of a sound source according to a sound which they received the time difference, thus accepting module may not be required to accept the signal by synchronizing the sound FM.

Question 3

Zhuo greatly, and now the rules too late, we are full sophomore first time. Prior to this I have completed the testing and production of the main control board, responsible for the program team are also working, we also intend to neural network into the PID.

But now the rules too late, although there is a rule about before, but no more. The June school tournament, each team can only be out of a (traditional school students do laboratory car, we are for the first time) the current situation for those of us newcomers are very bad, it is likely to do it in a hurry case you can not beat the lab, so the school can not match, so the game is pulled very low cost.

插图（BING网站首页）

But from the beginning I have been working so cars of their own design and testing, network access reference material, they can feel that they are making good progress. Consequently do not know already from the original can work independently. Yesterday on my teammates and discuss, and perhaps this can not participate in the (teammates also want the security research), but we have prepared so many really want to play a smart car competition.

Zhuo would like to ask much, next year there smart car game? I want to participate again next year (our school sophomore next semester is the largest game time)

Re:
does this event competition encountered more often, resulting in the game now the preparatory work has not been able to finally implement. But for the next year (2021), preparations for the contest on time relatively well-off, will be held in conditions more fully.