Bricked Raspberry Pi Displays History

[eN0Rm’s] Raspberry Pis are much more than just another brick in the wall. He’s used the popular embedded Linux platform to build several small rear projection screens in a brick wall (Imgur link). Brick shaped metal enclosures were mortared into the wall of the building. Each rear projection screen is illuminated by a DLP projector which sits inside the metal enclosure. The Raspberry Pis sit on a shelf below all this.  The bricks are in a building in the Aker Brygge section of Oslo, Norway, and show historical facts and short videos about the local area.

[eN0Rm] could have used a PC for this task, the price for a low-end PC with a few graphics cards probably wouldn’t have been much more expensive than several Raspberry Pi’s with cases. However, this system has to just work, and a PC would represent a single point of failure. Even if one Raspberry Pi goes down, the others will continue running.

The current installation is rather messy, but it’s just a test setup.  [eN0Rm] has already been taken to task for the lack of cable management in his Reddit thread.  As [eNoRm] says – first get it working, then make it pretty.

[Ben Krasnow] Shows Us How A Crookes Radiometer Works

[Ben Krasnow] is tackling the curious Crookes Radiometer on his Applied Science YouTube channel. The Crookes Radiometer, a staple of museum gift shops everywhere, is a rather simple device. A rotor with black and white vanes rotates on the head of a needle. The entire assembly is inside a glass envelope. The area inside the glass is not at a hard vacuum, nor is it filled with some strange gas. The radiometer only works when there is a partial vacuum inside.

The radiometer’s method of operation was long misunderstood. Sir William Crookes and James Clerk Maxwell both believed that the vanes moved due to the pressure of the photons hitting the vanes. If that were true though, the radiometer would spin in the opposite direction it normally does when held near a light source.  It was eventually discovered that the system is a thermodynamic one. [Ben] proves this by cooling down the radiometer’s glass with a can of freeze spray.  The radiometer immediately begins spinning backwards, with no light source present.

From there [Ben] mounts the rotor of a radiometer inside his vacuum chamber, which many will recognize as the chamber from his DIY electron microscope. As expected, the vanes don’t spin at a hard vacuum. In fact, [Ben] find the vanes spin fastest when the pressure is about 7 mTorr.

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Hacklet 22 – Retro Console Projects

Everyone loves arcade games, and it didn’t take long for designers to figure out that people would love to take the fun home. The home gaming console market has been around for decades. Through the early days of battery-powered pong style consoles through Atari and the video game crash of the early 80’s, to the late 8 and 16 bit era spearheaded by The Nintendo Entertainment System and The Sega Master System and beyond, consoles have become a staple of the hacker home. This week’s Hacklet features some of the best retro console projects from Hackaday.io!

52001We start with [ThunderSqueak] saving the world with her Atari 5200 Custom Controller Build. For those who don’t know, the Atari 5200 “Super System” was an 8 bit system ahead of its time. The 5200 was also saddled with on of the worst controller designs ever. The buttons would stop responding after a few hours of game play. With 17 buttons, (including a full number pad), that was a pretty major design flaw! [ThunderSqueak] hacked a cheap commercial fighting game stick to make it work with the 5200. 12 individual buttons were wired in a matrix to replace the telephone style keys on the original 5200 controller. Atari’s non-centering analog stick was converted over to a standard 4 switch arcade style stick. [ThunderSqueak] did leave the original pots accessible in the bottom of the enclosure for centering adjustments. Many 5200 games work great with the new setup.

 

snes[DackR] is bringing back the glory days of Nintendo with Super Famicade, a homebrew 4 SNES arcade system inspired by Nintendo’s Super System. Nintendo’s original Super System played several customized versions of games which were available on the Super Nintendo Entertainment System (SNES). [DackR] is building his own with parts from four SNES consoles. He’s also adding a few features, like a touch screen, video overlay, and enhanced RGB.

He’s going to add custom memory monitoring hardware, which will allow him to check how many lives a player has left and handle coin operation, all without the original Super System Hardware. If you’re curious what the original Super Systems looked like, check out Hackaday’s Tokyo Speedrun video.You might just catch a glimpse of one!

rgb[Bentendo64] is improving on the past with RGB For ‘Murica. European systems have enjoyed the higher quality afforded by separate red, green and blue video lines for decades. North American gamers, however were stuck in the composite or S-Video realm until shortly before the HDTV age. [Bentendo64] had an old hotel CRT based monitor, and decided to hack an RGB input. After opening up the back of the set, he removed the yolk board and added direct inputs to the video amplifiers. We’re not sure if this mod will work with every CRT, but it can’t hurt to try! Just be sure to discharge those high voltage capacitors before wrenching on these old video systems. Even if a set has been unplugged for days, the caps can give a seriously painful (and dangerous) shock!

snes2[Ingo S] is also working to improve the SNES with SNES AmbiPak, a mod which brings ambient lighting and “rumble pack” controller feedback to the vintage Super Nintendo. [Ingo S] used the popular SNES9X emulator to figure out where game data is stored while the SNES is running. His proof of concept was the original F-ZERO SNES game. [Ingo S] found that Every time the player’s car hits the wall, the system would perform a write on address 3E:0C23. All he would need to do is monitor that address on the real hardware, and rumble the controller on a write. The real hardware proved to be a bit harder to work with though. Even these “slow” vintage systems clock their ram at around 3MHz, way too fast for an Arduino to catch a bus access.  [Ingo S] is solving that problem with a Xilinx XC9572 Complex Programmable Logic Device (CPLD). CPLDs can be thought of as little brothers to Field Programmable Gate Arras (FPGAs). Even though they generally have less “room” for logic inside, CPLDs run plenty fast for decoding memory addresses.  With this change, [Ingo S] is back on track to building his SNES rumble pack!

It feels like we just got started – but we’re already out of space for this week’s Hacklet! As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Extreme Repair Of A Burnt PCB

[xsdb] had a real problem. His JBL L8400P 600 watt subwoofer went up in flames – literally. Four of the large capacitors on the board had bulged and leaked. The electrolyte then caused a short in the mains AC section of the board, resulting in a flare up. Thankfully the flames were contained to the amplifier board. [xsdb’s] house, possessions, and subwoofer enclosure were all safe. The amplifier board however, had seen better days. Most of us would have cut our losses and bought a new setup. Not [xsdb] he took on the most extreme PCB repair we’ve seen in a long time.

After removing the offending caps and a few other components, [xsdb] got a good look at the damage. the PCB was burned through. Charred PCB is conductive, so anything black had to be cut out. The result was a rather large hole in the middle of an otherwise serviceable board. [xsdb] had the service manual for the JBL sub. Amazingly, the manual included a board layout with traces. Some careful Photoshop work resulted in an image of the section of PCB to be repaired. [Xsdb] used this image to etch a small patch board.

The amplifier and patch were milled and sanded to match up nearly perfectly. Incredibly, all the traces aligned. [Xdsb] soldered the traces across the join with small sections of wire and solder wick. After soldering in some new high quality capacitors, the amplifier was back in action!

If you’re a big fan of burned PCB’s, check out Hackaday Prize Judge Dave Jones latest EEVblog video, where he works on a Ness home alarm panel with a similarly cooked section of FR4.

[Thanks for the link JohnS_AZ!]

Hackaday Prize Judge Elecia White Writes Tell-All Blog Post

The awarding of The Hackaday Prize is nearly upon us!  With just over a day left to go, Launch Judge Elecia White has decided to spill the beans and write a blog post about which of the five finalists she thinks should win. We don’t want to spoil the surprise… but what the heck, she wants them ALL to win.

ChipWhisperer because it brings high-end hardware security tools to the masses.

SatNOGS because it brings space to your back yard,

PortableSDR because of its great waterfall display,

ramanPi because come on, it’s a freaking spectrometer!

Open Source Science Tricorder because it uses sensors to help us see the science in the world around us.

Elecia knows how much time, effort, and passion went into these projects, and how each one embodies the open and connected spirit of The Hackaday Prize. Only one day remains before the big event in Munich, and the announcement of the winner.

An Interview With Tesla Battery Hacker [wk057]

We covered [wk057] and his Tesla Model S battery teardown back in September. Since then we had some time to catch up with him, and ask a few questions.

You’ve mentioned that you have a (non hacked) Tesla Model S. What do you think of the car?

It’s the best car I’ve ever driven or owned, period. Not to get too into it, but, I love it. I’ve put almost 20,000 miles on it already in under a year and I have no real complaints. Software feature requests… but no complaints. After almost a year, multiple 1700-miles-in-a-weekend trips, and an overall great experience… I can never go back to a gas vehicle after this. It would be like going back to horses and buggies.

A salvage Tesla Lithium battery had to be expensive compared to a Lead Acid setup. What made you go with the Tesla?

Actually, if you consider that the Model S battery is already pre-setup as a high-capacity pack, contains the wiring to do so, and the modules are much more energy and power dense than any lead acid battery bank, it’s actually almost cheaper than a comparable lead acid bank and all the trimmings.

I haven’t officially weighed them, but the modules from the Model S battery are roughly 80 lbs. 80 lbs for a 5.3 kWh battery is around 15 lbs per kWh, which is impressive. For comparison, a decent lead acid battery will have a little over 1 kWh (of low-rate discharge capacity) and weigh almost the same.

Also, the Tesla pack is much more powerful than a lead acid bank of the same capacity.
Generally a lead acid battery bank would have a capacity that would only be realized with slow discharges, so, 1/20C. Much over that and you sacrifice capacity for power. 1/20C for an 85kWh pack is only 4.25kW, barely enough for a central air unit and some lights without losing capacity.

Now the Tesla pack can be discharged (based on how it does so in the vehicle) at up to 3.75C for short periods, and at 1/2C continuously without really affecting the overall capacity of the pack. That means I can run 10x more power than lead acid without a loss in overall charge capacity. Leads to a much more flexible battery solution since the loads will, in reality, always be so low that this will not even come into play with the Tesla pack, but would almost always be a factor with lead acid.

Charging is also somewhat better with the Tesla battery. Charge a lead acid battery at a 1/2C and it will boil. Charge the Tesla pack at 1/2C (42kW) and it might warm up a few degrees. Oh, and the charging losses at high rates are much less than lead acid also.
Overall, without continuing to yack about the technical aspects, it’s just a much better battery, takes up less space, weighs less, and has more power available.

There are likely decent arguments for other solutions, but the rest aside, this one won out because it was definitely more interesting.

Click past the break to read the rest of our interview with [wk057]!

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