#hackandtell

Algardas made a remote-controlled drone-rover. He used a Raspberry Pi, wheels from a hover board, and even some parts from an ice-cream machine. Rover is equipped with several 'eyes': an infrared and a normal webcams, it can be controlled via a WebAPI and a smartphone with no lag over 4G connection, and it runs from a battery from his old tricycle.

Renardas retrofitted a VEF Spidola 232. He upgraded to LiPo battery, bluetooth module and replaced speakers and added an amplifier with intention to keep the original design of the device. He then changed some buttons to respond to functions and included a charge LED, it also shows how much battery charge remains.

Kęstas figured out how to make his estate Volvo car (which is a rather large vehicle) make a beeping sound during the reverse when the hazard warning lights are on.

Giedrius made a bunch of multi-functional paint and brush stands for his desk. He designed models from scratch and used laser-cutter to make parts.

Darius presented Drowex, a pixel-art project he was brewing for 6 years and took 6-7 months to code. The idea came from nostalgia for retro games and the need to calculate how many post-it notes it would take to make a pixel art picture on the wall. The initial project was lost due to a hard-drive failure, and a newly re-written Drowex is no running on the Docker in the VM. Heres the link to the project: https://drowex.com/

Renardas told us about a TVIP box for TV that was running an old android and about to be thrown out as it allegedly didn't work as intended. Renardas made his research, some reverse engineering, and figured how he could replace android with something that works a lot better like  LibreELEC, and also control the module with a phone. A longer description can be found in his blog: http://9v.lt/blog/tvip-s-box-v-410-libreelec-installation/

Kęstutis went on a long-winded description of a deconstruction of an Opel Insignia gearbox and things he learned and discovered while doing it. His conclusion was that it can be repaired if needed while this part is often discarded due to a lack of understanding of how it functions.

Martynas V presented his visual code interpreter that generates a moving pattern - by changing different values, the visual will change. Projects support coding in C++ and use WebGL to display the result. You can n find live demo here: https://gi.ro.lt/static/toy/toy.html

Renardas re-arranged and optimized 25 odd server racks around the university and dorms he is working for. He had no previous experience and was lacking some resources so project included a lot of learning. A lot of previous wiring was chaotic, haphazardous, and sometimes even unsafe.

Kęstutis Motekaitis made an oven that controlled and sustained temperature with an Arduino micro-controller. As a nice bonus - instead of a usual sound signal it can chirp a different musical tune. Box has a Bluetooth module so the temperature can be monitored from a mobile phone.

The other Kęstutis fixed hinges on his laptop as they were broken and could not support display anymore for around 3 years now. The repair is rather crude-looking with machine screws and nuts but robust non the less.

Melitonas continued his story about the smart home (prev. on HnT #38). He told us about the usage of Smart Assistant and how it could be used for automated opening of the gates or arming the alarm. He used RaspberryPi to run the compatible software. There are failsafe's in place to make sure the system remains operational even if the electricity cuts out. Overrides can be issued on demand as well, for example in case Melitonas needs to stop the gate in the middle of opening or closing.

Renardas gave an introduction to airsoft and what it involves. He made a multiple mode airsoft timer bomb to make scenarios more competitive. The 'bomb' can be diffused by entering a correct code on the keypad and will time-out depending on number of failed attempts. While there are plenty code and DIY schematics samples available online, he wanted to make one from scratch. This involved printing a PCB, where Renardas failed to account for ground correctly and had to fix it by soldering in some wires. The next step is adding a siren, and the outstanding piece is still in transit. 

Anna gave a short presentation of screen replacement for an e-book. There wasn't much of a challenge, just some precision and diligence, really. Luckily, nothing else was faulty and the book is back to full operational.

Algardas shared his trials and tribulations of trying to install a pull-up bar in the corridor. One destroyed electric wire later, he had to repaint the entire wall. Eventually he succeeded and compiled a rather robust solution, that can be used to hang hammocks or a swing.

Ričardas presented his compact CNC 1419 project. Due to limited space, this was an optimal solution for him. It cost around 300 EUR and proved to be robust and reliable, the software runs steadily off an old Pentium PC with an SSD drive. The use has its own nuance, such as what materials the mill can handle, and what cutters can be used for each. Some bits and bobs were 3D printed as well.

Antanas shared his experience replacing a cracked screen on a tablet. He ordered a replacement screen from aliexpress. He managed to grab a disassembly kit from Lemona just before the lockdown, so he had some useful tools handy. He removed the old screen carefully and removed any glue residue. Luckily the camera was not affected. The replacement worked perfectly. Unfortunately, the new screen didn’t last as long and got cracked, too.

Renardas presented the first stage of making a buggy, it was the first time he ever made one. He had an old engine that he could use, he then acquired parts from here and there - clutch, sprocket, supports, brakes, steering wheel all have come from different places - a scooter, a tractor, and even a motorbike. He also had a custom-made seat. Unfortunately, the engine failed during one of the test drives and needed replacing. Renardas managed to obtain an engine from carting, luckily. With some modification, his buggy was back on the road, and the work continues. More info on his blog.

Martynas opened the event by talking about the enclosure he made for his Ender 3 3D printer by using two IKEA tables. He shared there is a whole set of 3D models one can print and list of items that can be used to turn two tables into an enclosure with a set of drawers. He ordered some Plexiglas to make doors and side panels and it turned out neatly. Here are the drawings of drawers and accessories.

Giedrius shared his experience of making a MPCNC. It came out rather massive and sturdy, but it works as intended. He deliberately picked a more powerful motors and longer beams to get the maximum working surface out of it, the setup also features an LPT interface. Giedrius showed some examples of the work he has done on the CNC - parts of the costumes he's working on.

Nerijus spoke about his laptop battery database - he acquired a significant amount of used 18650 batteries, measured the voltage and capacities and cataloged everything in an Access database. The idea is to re-use them for future projects, monitoring if any overheats or indicates any voltage swings (that could mean it's faulty). Here is the link to his video https://youtu.be/Pr4piKQCeCs

Anna was the last one, she spoke about the challenges of repairing a curtain and film counter on a medium format Kiev 60 camera. The old lens that went with is also needed repairs and cleaning. Unfortunately the test film wasn't processed on time, so she couldn't show the results.

Melitonas explained what defines a smart house - it's not just adjusting brightness of your led lights, it's being able to control so many more things around the house. There are many advantages to it: it's safe, highly flexible, and can save you money by switching off the appliances you don't need at the moment. There are a lot of technical aspects that need to be taken in mind - cabling, steady signal and appropriate relays and switches.

Marius presented his DIY tilt-shift lens made from a piece of flexible pipe and Mir 1B lens. The idea behind tilt-shift lenses is to move the focus plane the way that it allows to avoid perspective distortion of the buildings, or allows to get everything in short range focused. These lenses are actually rather pricey, however there are several ways one could make their own.

Nerijus briefly spoke about his DIY cart for carrying cargo (a boat and bags). He used aluminium pipes and 3D printed brackets with 100% infill. The cart is expected to carry around 50-60 kg of weight if needed.

Algardas showed his solution to run a NAS server at home by laser-cutting the box and filling it with rock-wool to dampen the noise and vibration. It was somewhat successful and is still a work in progress.

Anna shared her experience repairing a vintage bellow camera Agfa Billy I (from around 1956). She thought she got the focus ring repaired, however the film came back from the lab all blurry. As it turned out, the actual focus ring was stuck for good and took some rounds of different penetrating solvents and temperature swings to get it unstuck. Bellows needed some re-sealing too, gasket silicone was perfect for the job. After some focus calibration, Anna just finished the second test film roll, and hopefully it's all good now.

Darius spoke about making a variable bench power supply more useful and safer in long term experiments by connecting it to WiFi. He added esp8266 with esp-link firmware and developed a driver for controlling the power supply. The driver part took a lot more time then it should due to misleading documentation. However he managed to get it working as expected.