With reflow soldering, sometimes close is good enough. At the end of the day, the home gamer really just needs a hot plate or an old toaster oven and a calibrated Mark I eyeball to get decent results. This exhaust fan-equipped reflow oven is an attempt to take control of what’s perhaps the more challenging part of the reflow thermal cycle — the cool down.
No fan of the seat-of-the-pants school of reflow soldering, [Nabil Tewolde] started with a cast-off toaster oven for what was hoped to be a more precise reflow oven. The requisite temperature sensors and solid-state relays were added, along with a Raspberry Pi Zero W and a small LCD display. Adding the cooling assist started by cutting a gaping hole cut in the rear wall of the oven, which was then filled with a short stretch of HVAC duct and a stepper-controlled damper. The far end of the duct was fitted with a PC cooling fan; while it seems sketchy to use a plastic fan to eject hot air from the oven, [Nabil] says the exhaust isn’t really that hot by the time it gets to the fan. At the end of the reflow phase of the thermal profile, the damper opens and the fan kicks on, rapidly cooling the oven’s interior.
Unfortunately, [Nabil] still needs to crack open the oven door to get decent airflow; seems like another damper to admit fresh air would help with that. That would complicate things a bit, but it still wouldn’t be as over-the-top as some reflow builds we’ve seen. Then again, that calibrated eyeball thing can work pretty well too, even without a toaster oven.
The build is essentially a giant bellows, but the manner in which it operates is unlike anything we’ve seen previously. To shift the large pusher plate inside back and forth, [Matt] initially experimented with building his own linear motor out of coils and magnets. After that failed, he began to tinker with a system of moving a magnet back and forth through a tube with water pressure from a pump, which would then drive the pusher plate through magnetic coupling. This looked promising, but reversing the flow proved difficult. After building his own set of water valves to change the flow direction, the bellows began to work slowly, but with limited performance. Realizing the valves weren’t up to scratch, [Matt] rebuilt the system with 10 pumps, set up in two banks of 5. With the pumps hooked up in series, they supplied plenty of pressure to force the bellows back and forth. Reed switches were used to reverse the flow at either end to make the bellows run continuously.
In testing, the bellows compared well with a bank of four large case fans, though at 20 times the size. Suffice to say this is not exactly a compact solution. We look forward to seeing [Matt] do more with the bellows, with his intention being to use it as the primary cooling system for a computer. Of course, if this looks too complex, you could always consider a mineral oil setup instead. Video after the break.
With Sony and Microsoft still a month away from the public release of their next-generation game consoles, you’d expect technical details of their respective systems to still be under a veil of secrecy. But both companies look to be taking things a bit differently this generation, as it becomes increasingly clear that modern consumers are interested in what makes their devices tick. Today, Sony really threw down the gauntlet by beating the tech media to the punch and posting their own in-depth teardown on the new PlayStation 5.
Unsurprisingly, the video after the break is almost entirely in Japanese. But even if you don’t know the language, there’s plenty of interesting details to be had. For one thing, the heatsink and fan that cools the PS5’s AMD CPU and GPU are collectively so massive that they appear to take up most of the console’s internal volume.
In fact, the heatsink itself is so large that the motherboard is actually mounted to it instead of the other way around. So if you want to take out the board, you have to unbolt it from the heatsink and remove it first. In the process you’ll expose the unique liquid metal thermal compound that Sony apparently developed specifically for this application. Good luck to you if any dust gets in that expensive-looking goop.
It’s also interesting to note that, unlike the previous two generations of Sony consoles, the PS5 has no discrete hard drive. Instead, onboard flash with a custom controller is used to provide 825 GB of storage for software. Hopefully Sony has put the requisite amount of R&D into their wear leveling, as a shot flash chip will mean a whole new motherboard. That said, gamers with extensive collections will be happy to see there appears to be an expansion bay where you can install your own M.2 drive.
Most of us reach for an over-the-counter medicine if we have occasional pain, but menopause doesn’t act like that. Hot flashes don’t build like a headache, dizzy spells don’t wait for a good time, and panic attacks don’t announce themselves. Predicting and addressing sudden hormone shifts is the intent behind Menesto, a vest with sensors, cooling apparatus, and a companion app.
A thermometer and humidity detector monitor the skin for spikes in temperature and moisture to recognize when the wearer is having a hot flash. When an event is registered, a fan blows over a Peltier panel’s cool side and hopefully provides enough chilled air inside the vest. A Peltier panel is a thermoelectric heat engine that moves energy away from one ceramic plate to another, so one half gets cool while the other heats up. Power comes from rechargeable 18650 batteries and all the hardware talks to an ESP8266 on a NodeMCU running Arduino.
If you live anywhere near the tropics, air conditioning isn’t a luxury but a necessity. The problem however is that humid climates can cause conventional air conditioners to draw more power to dehumidify the air than it requires to just cool it, which increases the power needed to run the unit. Back in 1963, there was a proposal to create a cooling system that didn’t foster condensation and couple it with different methods of removing humidity. Researchers in Singapore have now created such a system. It uses a membrane that is permeable to infrared radiation but prevents condensation around the cooling unit.
You can see a video of the apparatus in a pavilion in the Singapore heat in the video below. Chilled water runs through tubes behind a membrane that passes thermal radiation. Since the tubes are not exposed to the ambient atmosphere, condensation is minimal. But heat radiates from the warmer area to the much colder area of the tubes.
Passive homes are a fairly recent trend in home building, but promise a future with minimal energy inputs in our day-to-day. One of the challenges in this year’s Hackaday Prize is to envision ways to add utility to earthen homes often used in refugee camps where there is a housing crisis. Adding passive utilities to these adobe buildings would be a fantastic upgrade, so [Cat] decided to tackle the challenge by creating a refrigerator that needs no electricity.
The the plan for the device works by using evaporative cooling to reduce the temperature in a small box which can be used for food storage. Of course, using evaporative cooling means that you need ready access to water and it likely won’t work in a humid or cool environment, but systems like these have been in use for centuries in plenty of places around the world. [Cat]’s plan is a little more involved than traditional methods of evaporative cooling though, and makes use of a specially painted chimney which provides the airflow when heated by sunlight.
The project is still in its infancy but it would be interesting to see a proof-of-concept built in a real-life passive house in an arid environment. Unfortunately, those of us in humid (or tropical) environments will have to look elsewhere for energy-efficient cooling solutions.
These pistons are printed from high-purity aluminium alloy powder that was developed by German auto parts manufacturer Mahle. Porsche is having these produced by Mahle in partnership with industrial machine maker Trumpf using the laser metal fusion (LMF) process. It’s a lot like selective laser sintering (SLS), but with metal powder instead of plastic.
The machine dusts the print bed with a layer of powder, and then a laser melts the powder according to the CAD file, hardening it into shape. This process repeats one layer at a time, and supports are zapped together wherever necessary. When the print job is finished, the pistons are machined into their shiny final form and thoroughly tested, just like their cast metal cousins have been for decades. Continue reading “Porsche’s Printed Pistons Are Powerful And Precise”→