If you were reading my blog you probably know that I play airsoft for several years.
Here the sites that we play in don’t change often and in most places airsoft grenades can be used.
In Lithuania, airsoft grenades are essentially firecrackers with up to 1g of powder placed in a small container and filled with BBs, dry peas or anything that is kinda round and represents shrapnel. Very simple, effective and you don’t have to pick it up after using.
So, in that time I noticed that a device that ignites a grenade when I want to at a set location would be very useful when taking back positions from enemy whenever they would barricade themselves in and I dubbed thee – REMDE. For open fields, I’ve come up with a solution that I wrote about here to fling grenades much farther than I could by hands.
The device functions very simply – the bare minimum is made up of two devices – the transmitter and the receiver.
Whenever I go into a nice position that I know enemy is going to sit there when they take it, I place the receiver down somewhere, attach an e-match (the very same used for firework shows) to it and attach the grenade to the e-match.
Now when I need to, with one button, I can check it’s status if I have multiple receivers and I forget if I had used it. With another button I can send a command to ignite the e-match.
So some time ago I was asked to make this apparatus – a (flash?) light with intensity controlled remotely. The idea was that it could be hanged in some place and aimed at what needed to be illuminated and after that you should be able to remote-control the light intensity.
The light source (doesn’t need to be very bright) must be able to have enough power to last for at least a week sitting in idle (only listening to radio signals) and a few hours of constant illumination at night. Depending on the darkness of the night the light source intensity could be adjusted. However the distances over which it would be controlled are 200-300m.
The whole receiving and lighting part needs to be modular – battery, controller and light must be separate for easier handling.
This is pretty easy, fun and a straight-forward task to do with arduinos, but the radio modulation presented a challenge, since it’s the first time I have touched these and SPI as well.
Turns out that there aren’t many solutions to this. There exists a few radio modulators, but they all go up to 100m at best AFAIK. However there is one – LoRa and that’s what I used.
Reading different sources I could gather that a normal distance for LoRa is a few kilometers and that’s what it was designed for. The distance you could reach obviously depends on the environment you’re in, the equipment you use (antennas, power source) and the settings you set for modulators.
LoRa is able to reach such distances with the cost of transfer speed. Meaning it’s ideal to send some sensor values from time to time and not for something that needs to pass a lot of data or pass that data very fast.
So I got to know all the requirements and started to sketch out ideas of how I might construct this.
Hello. Let’s say you have a large sum of computers in your organization that are connected to a domain and some of those computers could be turned off for the night (library, computer class, etc.), because after using them not everyone turns them off and they are kept powered on through the night. That bothers me because ~50 computers are wasting energy! and so I came up with a powershell script that powers off the selected computers at a schedule, in my case I set it to run at 19:00 every day.
After letting it run for a couple of weeks, I think it seems to be working pretty well… You have to configure it though, by adding computer names with their full domain name and their MAC addresses in the array and that’s it. Log file is created at the location you specify (C:\ now) with computers that were shut down.
Script can be found in my project folder here.