Designing an Automatic Camera Tracker

Project Info

Case

We were requested by one of our clients to design an automatic camera tracker device. The client’s main objective was to have the camera set up on his tennis court, so while he was playing tennis, his videos could be captured by the tracking system.

Requirements

  1. The device’s Tracking distance was to be up to 50 feet with frame adjustment to preserve image quality.
  2. This device was expected to mount onto a stand like a tripod.
  3. It was to have an attachment on its top to accommodate small cameras such as a GoPro, a cell phone or tablet.
  4. The top of the device needed to have a camera quick release plate.
  5. The device was to have a storage space so that the captured videos could be stored in it.
  6. The device was to be connected to the client’s computer or mobile to report its observations.
  7. The device was to be powered by both the AC power and battery.
  8. The design was to be cost-effective.
  9. The design was to be delivered in 6 months.

Challenges

  1. The design had to have a good response time so that it could track the moving object during its fast movements
  2. The design had to be able to capture for 6 hours without any external supply
  3. The other challenge was to make the cost as low as possible
  4. The final challenge was the design and prototyping time that was supposed

Solution

There was already a similar design in the market with 3 years of development time but we were requested to get the product ready within 6 months. Besides, there were a variety of options for every part of this design and so the details were to be worked. This step took several weeks and after a Memorandum of Understanding was prepared with the client the design team started its work. Some of the basic elements of the work included the following.

  1. Primarily, different options were considered. For example, a good option seemed to be using IR sensors because they were easy to implement; however, after more research and practical tests, the designers concluded that it was not suitable for an outdoor fast response application because the response time was low, and the frames could not catch up the movement. Similarly, some other options including using a Raspberry Pi, a webcam and a 12 Vdc stepper motor were studied and each had their setbacks.
  2. Having considered different options, finally, a design based on using Arduino module and high precision GPS modules was chosen.
  3. The design was composed of two electronic boards, one attached to the moving object (in this case, the tennis player) and the other one attached to the tripod controlling the motion of motors and capturing the video.
  4. The Transmitter board was equipped with a GPS module that took the location of the moving object and would send it to the receiver that was fixed on the tripod via a Bluetooth module. It also had a rechargeable battery to supply the electronic circuits.
  5. The whole receiver board consisted of a Bluetooth module to receive the data sent from the target or transmitter board, a compass Module to determine the correct location of the whole system, a Camera Motor Driver Circuit which controlled the camera section according to the position of the target section and a charging circuit in order to power up the circuit. The two locations were compared and based on the relative location, the movement of the stepper motors was determined. This way the camera was always directed towards the player.
  6. A major challenge of the project was the firmware that was finally done and tested.
  7. Some of the design specifications were as follows:

It is used only for outdoor application

  • Rotating angle 180o
  • Maximum weight of the camera = 3Kg
  • The transmitter had a booster which stepped up the voltage from 3V to 5V
  • Receiver having a boosting circuit which stepped up the voltage from 3.7V to 12V (since the operating voltage of the stepper motor was 12V)
  1. The below images shows the top and side view of the transmitter box. The red light indicates the power signal for the transmitter and the green one indicate the availability of the GPS signal. The antenna which is placed above the transmitter box was connected to the circuit inside the box via a third hole.

For the motor, a 12Vdc stepper motor was used to rotate the camera and make it focused on the moving player.

For the stance, a tripod stance was chosen to assemble all the components including the motor, board and the camera.

Description

After about 8 months of close work with the customer, finally, a fully functional prototype was prepared and tested. The final prototype met all the requirements and was later submitted to the client. Due to the use of a low-cost GPS module for the testing purpose that had low-accuracy, the response time was low, and so the motion of the camera was stepwise. However, once the client changed the module with a high accuracy module, this issue was resolved considerably. While the final setup could be improved and enhanced in terms of the response time and also its range, the work was satisfying and met the requirements.

Client:
Nancy P.
Date:
July 26, 2018
Location:
LA, US
Category:
Electrical and Electronic Engineering