Not long ago I was tasked to make a tool to manage Moodle courses by moving them through categories, creating and cleaning them up. Now I had to make some way to “refresh” the course participants and that means unenrolling teachers and managers, assign different roles, suspending students, adding students, all that stuff.
This was going pretty good and easy until I hit upon a web service function
core_enrol_edit_user_enrolment. It’s an
External function that updates a given user enrolment, it is needed to suspend students from a course.
From the official API docs, we can see that it takes in required arguments courseid (User enrolment ID), ueid (User enrolment ID) and status (Enrolment status).
The problem here is with a ueid (User enrolment ID) argument because there’s no function that returns such an ID. At least I wasn’t able to find one easily accessible and I had to make my own web service function to get that ID.
At the Kaunas Makerspace that I visit very often to do various projects, most tools there are donated, some are bought and some tools are self-made (like a spot-welder that I used to connect batteries).
In the case of cordless drills the situation was never good. There are a few of them, but all are missing batteries or have dead packs and sometimes when you need to screw or drill something a bit it’s a little annoying, so we made a few from old LiPo (18650) cells that we salvaged from laptop batteries for Meec cordless drills. They have a very neat battery holder design – batteries simply slide in.
Making of the battery pack is easy, hardest part was to make a case for them and of course a charging station.
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.
This is my third attempt at making my life easier with maintaining a fire. I wrote about other attempts here and here and it looks like that this project has a never ending continuity, since it’s such a useful device…
This device (like previous ones) are to ensure I keep my eyes out of smoke and lungs in proper working condition and this version design was inspired by other devices that are for sale on Amazon or eBay, but they are chinese made tools and require batteries to work… I thought I could make it a bit better with rechargeable batteries, a small display to see how much power is left, a normal on-off switch and possibly with a better air volume output. Also as an added bonus I thought I could use it to inflate a mattress a bit, so that I don’t have to do it with my mouth and then sit down a bit being dizzy AF. Obviously this doesn’t create enough pressure to inflate it all the way though.
I remember a scene in a “Tom and Jerry” cartoon episode “Barbecue brawl” where spike was blowing into charcoal to get the fire going and of course that didn’t go well, if only he had this device though :D
At work we have a couple of info kiosks (we call them terminals) that we bought from some company many years ago, but the support has ended also many years ago, so they abandoned them. The kiosks were running some custom software that the company had thrown together, it didn’t seem very professional from an IT guy’s perspective, because those kiosks were lagging and eventually would hang and would need a manual restart. We were living with this for some years until eventually both kiosks just hanged and didn’t properly boot for no reason.
After this we decided to look for a solution and whadya know – there is one free and simple solution with plenty of customization options for our needs. It fits our situation perfectly and it’s called “Porteus Kiosk”
“Porteus Kiosk” is a kiosk edition of Porteus, a portable Linux OS based on Slack and it seems to be popular enough to have a Wiki article for it…
Our kiosks have a “Elo TouchSystems 2515” monitor (meaning there’s no mouse or keyboard) and a “ZOTAC ZBOX ID13” mini-pc which has very low specs like an old Intel Atom CPU and 2GB of RAM.
I quickly downloaded the latest ISO (4.7.0 at the time of writing) and installed it to a flash drive, booted it up on the kiosk to test out and right away noticed some issues that I’d need to fix. The issues were that the system didn’t have a virtual keyboard, like it wasn’t primarily targeted for touch info kiosks (but PK supports most touch devices out-of-the-box) and also in my case, Elo touch screen doesn’t support multi-touch (for scrolling for ex.) and so you’d need to drag the scrollbar, but Firefox scrollbar for that Linux version is very thin and were out of touch bounds, therefore most pages couldn’t be scrolled down the traditional way. I had to find solutions to these.
Linksys routers, and I’m talking about WRT54g series, are not so popular anymore. In fact they are pretty much dead, as a technology, at this point. Technology that once were notorious among routers with their endless capabilities router-wise. Projects like DD-WRT and OpenWRT started with these WRT54 routers and now look at them. But because of their slow wifi and ethernet speeds, lack of modern wifi standard support and old chips they became obsolete, but among hackers and makers the name wrt54g is known very well. And when wrt54gl came out in 2005 it was the best-selling router of all time.
Today these routers still can be used for some projects (because of their extensive hackabilities software- and hardware-wise) where network speed is not the top priority. They can probably be compared to small raspberry computers with wifi and ethernet ports already available.
As it happens, I have a couple of these laying around at work (more specifically wrt54gl v1.1) and I thought maybe I could make a piratebox out of one of them. So I started gathering information if that would be possible. I didn’t find any info if piratebox would install properly, so I thought I could just try anyway and see how that goes… and the first thing I needed to do was to install USB ports.
Slingshots are fun. They have always been fun, many years ago they were more of a tool for hunting small animals than fun, though. Now we have huge communities, YT review channels and all that stuff oriented around slingshots and they are very passionate about them.
For me a slingshot was just a fun thing to launch rocks with and I haven’t used one in quite a while, I think since I was a kid even. But now with my recently acquired hobby (airsoft) that need to use one came up when I saw in a couple of games that some sort of a grenade launcher would be highly beneficial because I could reach longer distances, throw much more accurately and make it fly to the target faster. A slingshot is the perfect solution to this problem, however I wanted a foldable one for easy carrying in a backpack or a pouch on my tactical vest.
To my surprise there wasn’t any to buy, well except one from AliExpress, but it was made more to look good than be practical to use, also it was a bit too expensive and I didn’t want such a fancy thing. It’s sold without rubber tubes/bands and without a pouch and is too small to shoot my home-made airsoft grenades.
So I thought I could make one myself – a foldable slingshot.
Earlier I wrote that I like to play airsoft and that I made a gun case here. Naturally when doing something competitive, with time, a need for more/better accessories grows, and one is the UHF radio (or walkie-talkie for some) which is really handy when communicating with your teammates in the field.
At work a long time ago I found a pair of Kenwood TK-3101E radios that were long forgotten in an abandoned room gathering dust in the dark – one was missing a battery pack and one had a dead battery pack, but I didn’t have a need for them at the time so I didn’t do anything. Now I thought I could revive these radios for a second life and use it for myself, so I took them out and tried to use.
By them I mean just one that still had a battery pack. Seems that Kenwood has a model name for anything they make (or made, not sure how it is these days), so the battery pack has a model name KNB-14, which originally is a 600mAh Ni-Cd. Needless to say that Ni-Cd is shit and battery was dead – didn’t hold a charge of 5 hours for more than 30 minutes while being turned off.
But that didn’t surprise me, since this model was released around 1999…
Lighters have gone a long way since traditional ones. Now we have things like a so called “Tesla lighter” – which is actually an electric arc generator and you can ignite stuff with it.
These lighters are super cool, some have a coil and a single arc (2-in-1), some have just a double arc tip. They all look pretty nice and cost around 8-15€, depending on whether you want cheap or functional or nice-looking.
Usually Tesla lighters emit a high-pitched frequency sound when activated, maybe it’s just with cheap ones, not sure. They also work in all conditions – wind can’t blow it out (although since it’s all electronic, water isn’t his friend, unlike with flint lighters when you just have to wait for the flint to dry).
Since I play airsoft and use grenades (which are made with firecrackers), I use a cheap jet lighter and sometimes it’s hard to ignite them reliably. It’s resistible to medium winds, but not reliable enough to work on the first try and so I have to keep pressing it to get some fire going. It’s time consuming and enemies can always hear the clicking.
Yes, I could buy a more expensive jet lighter that is much more reliable, but I don’t want to spend a lot of money on that. Tesla lighter seems like a good alternative, but I didn’t want to buy one because they are a bit costly for such a thing and also they don’t have any way to hang them the way I want.
Recently I started playing airsoft, I came across it when a friend asked me if I wanted to try it and the game he wanted to go to had a cool backstory. At the start I was skeptical about this pseudo-war, role-playing soldiers and stuff with fake guns but cool looking gear. After a few games with rented equipment, and the first game’s first half hour being somehow awkward until I encountered an enemy and got some bb’s shot in my leg that hurt, after that I started to like it a lot. Now I’m playing it every weekend with my own gear and an AK-47 imitation.
The gun that I bought came in a cardboard box, which isn’t permanent or convenient to carry. There are hard and soft cases to buy, but those, as with many things in airsoft, apparently, are a bit expensive. So I decided to make my own hard case, which is essentially a wooden box with a lid – nothing fancy.