The R&D story behind DJI Matrice 30 Loudspeaker and Spotlights Payload

The New 2-in-1 spotlights and speaker multi-payload for the DJI Matrice 30 drone have been released, its searchlight distance is 100 meters, and the speaker volume broadcast distance is 200 meters. small size and lightweight, but powerful performance.

First of all, we have to admit that the LP12 is not a perfect product. Too many painful or tangled compromises were made within the constraints of size and weight for our application purposes. This is our first 2-in-1 product for lighting and speaking. Before this, we have never tried to develop a 2-in-1 product for spotlight and sounding.

In June 2021, we received a list of development constraints for searchlights and megaphones and started pre-research work. In the beginning, we still planned to develop a pure spotlight and loudspeaker product, namely a microphone and a searchlight for the DJI M30 drone. At the end of August, a colleague from DJI suggested that we could give priority to developing a product that combines a searchlight and speaker. that is a multi-function 2 in 1 payload, the weight is about 250g, and the effective lighting and voice distance can reach more than 100M. Because when performing search and rescue missions, some areas, such as deep mountains, cannot be reached by vehicles. It is necessary to use the M30 drone, which is smaller and more portable than the M300, to carry out operations in the search and rescue area by carrying it on foot. During search and rescue, the drone uses a megaphone to broadcast in the air, informing the search and rescue target to maintain physical strength/go to an open place/put up a conspicuous distress sign, etc. At the same time, use an infrared thermal imaging camera to conduct a large-scale search, and then reduce the flight altitude after finding suspected hot spots. , Use searchlights and visible light cameras to confirm the target.

The product design is basically formed. Based on the new megaphone, we have added two quick-release interfaces on it, which can mount up to two searchlights with a power of 30W. In the preliminary calculation, adding one searchlight weighs 300g, and adding two searchlights It weighs 430g and has a beautiful and symmetrical appearance. It is only equipped with a megaphone during the day. At night, you can flexibly choose the number of searchlights according to your needs. You can also have compatible red and blue flashing lights. We are very satisfied with this exquisite design, but the DJI R&D department thinks that 300g is still too heavy. . Because the smaller the drone is, the more sensitive it is to weight. For every additional 70g of take-off weight, the battery life of the DJI Matrice 30 drone will be reduced by one minute. 20g. Considering that the M30 will be widely deployed in automatic airports, we finally decided to cancel the quick release design and try our best to reduce the weight on the premise of meeting the design goals.

Subsequently, we officially launched the project. First of all, it is the selection of LED wicks. The larger the luminous area of ​​the LED wick, the higher the efficiency and the brighter the brightness, but the corresponding condensing lens is also larger, which makes the light body The size became larger and the weight increased. Finally, we gave up the solution on the GL60plus and chose a new wick with the smallest light-emitting surface to control the size and weight of the searchlight. The efficiency of the first-generation GL60. After the weight of the DJI M300 drone searchlight body is reduced, the power of the motor that controls the pitch of the light can also be reduced. We specially ordered a smaller motor, which saved a few grams of weight.

Secondly, when the test audio files such as expulsion sound and large dynamic music were played continuously for a long time, the microphone overheated and burned out. First, use the hardware method to reduce the peak power, it will no longer burn out, but the shouting sound will also become smaller, which is absolutely impossible. If the power reduction is not enough, improve the design of the driver and strengthen the heat dissipation, so that it can withstand higher power. Audio that is not loud enough is boosted. Finally, the improved DJI M30 megaphone won’t burn out no matter how long the extreme audio file is played continuously.