Remote Operated Laser Pointer – Part 2

Remote Operated Laser Pointer – Part 2

In this post, I will continue on with describing the development of the remote operated laser pointer from my previous post. I recently procured a couple of DC 3.7V-12V Mini Wireless Remote Control Switch Relay Micro Receiver Transmitter System For LED Light Smart Home units from Banggood. This unit acts as a remote controlled relay supporting both normally open (ON) and normally closed (NC) configurations. I was looking to use normally open, and when triggered, to close the circuit.

Here is a closer look at both the transmitter and receiver. I’ve included some pictures of the internals of the transmitter unit as well. We are only temporarily going to use it, as I will explain further. The unit is tiny and light and just what I was looking for related with this project.

Using an approach as shown in this informative youtube post from PiddlerInTheRoot, the transmission codes of the transmitter can be detected. I used an FS1000A 433mHz Tx & Rx RF Radio Module

FS1000A – Transmitter and Receiver Pair

Next, I connected all the pieces together so that I could trigger a transmit event that lights up a test green LED and another to switch it off. I haven’t used the red laser diode for testing in this case, as I need to work on a compact circuit that would be able to power both the RC relay and the laser diode. More to come in my next blog post on this.

The distance between the Transmission assembly and the Reception assembly could be an amazing 160m in ideal conditions as this youtube video shows. Here is another video with a successful range test of over 350m with some modifications to the hardware, such as adding longer antennae. The Reception assembly has two circuits with their own power sources. One circuit powers the wireless remote control switch and the other powers the green LED.

The pypi python site has a project for sending and receiving 433/315MHz LPD/SRD signals with generic low-cost GPIO RF modules on a Raspberry Pi. There are two script files that are of use. Click on the links to go to the source code that’s written in python.

Finally, as usual, I’ve recorded a demo of this project in action. Here’s the video:

Quick view of the setup in action

Now with the RC relay, I can switch the LED on/off from python code. Once I sort out the power circuit issue, it will be possible to ‘build’ the final assembly of the remote controlled laser pointer. I’ll then mount this assembly on my RYZE tello drone. Then will do some tests on that. The most important test would be to check for the stability of the flight of the aircraft with the final assembly mounted on it. And of course, to check whether the laser pointer lights up while the drone is in flight.

Once these basic tests pass, it would be time to focus on capturing live video from the RYZE tello drone onto the Raspberry Pi and doing some object inference / detection using the Intel Movidius Neural compute stick 2 for deep learning . Based on finding certain objects, I would have the code switch the laser that’s mounted on the drone to ON status followed by off. This is really where the fun begins.

I will demonstrate this in action in my next set of posts in this series. Stay tuned!

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Posted by on February 17, 2020 in IoT, Programming