Industrial designer [Eric Strebel] has access to big, walk-in spray booths, but bigger isn’t always better. For small jobs, it’s overkill, and he wanted his own spray booth anyway. If you’re ready to upgrade from that ratty old cardboard box in the garage, look no further than [Eric]’s spray booth how-to after the break.
If you don’t already know, [Eric] is something of a foam core legend. He has several videos about model building techniques that produce really slick results, so it’s no surprise to see these skills transfer to a larger build. The booth is built from a single 40″ x 60″ sheet of 1/2″ foam core board, a furnace filter, and a vent fan modified to fit his shop’s system. The whole thing cost less than $200, most of which goes toward the fan.
[Eric] modified an existing spray booth plan to fit his needs and added some really nice touches along the way. All the edges are beveled and the unfinished faces are taped, so at first glance it looks like it’s made out of painted wood or melamine board. The furnace filter slides out one side for easy replacement and is braced with foam scraps so it won’t fall forward. The best part of this booth is the LED strips—they make for way better working conditions than the dim recesses of a cardboard box.
If you’d rather build a walk-in spray booth, why not make your own sliding barn doors, too?
We’re all too spoiled nowadays with our comfortable ways to erase and write data to persistent memory, whether it’s our microcontroller’s internal flash or some external EEPROM. Admittedly, those memory technologies aren’t exactly new, but they stem from a time when their predecessors had to bathe under ultraviolet light in order to make space for something new. [Taylor Schweizer] recently came across some of these quartz-window decorated chips, and was curious to find out what is stored in them. Inspired by the BIOS reverse engineering scene in Halt and Catch Fire, he ended up building his own simple reader to display the EPROM’s content.
The 2732 he uses is a standard EPROM with 32kbit memory. Two pins, Chip Enable and Output Enable, serve as main control interface, while 12 address pins select the data stored in the chip’s internal 4K x 8 arrangement, to output it on the 8 data output pins. You could of course hook up the EPROM to a microcontroller and send what you read via serial line, but [Taylor] opted for a more hands-on approach that lets him read out the data in a manual way. He simply uses a bank of DIP switches to set the address and control pins, and added a row of LEDs as display.
As you can see from the short demonstration in the video after the break, reading out the entire EPROM would be a rather tedious task this way. If you do have more serious intentions to read...
One of the reasons why the Arduino became so popular was the ability to program it with ease. It meant the end of big parallel programmers that would cost an arm and a leg. The latest installment of CircuitPython from [Lady Ada] and the team over at Adafruit is a library for programming AVR microcontrollers without a dedicated PC.
For the uninitiated, in-system programming or ISP for AVR controllers employ the SPI bus to write the compiled binary to the flash memory of the controller. The discount on the number of pins used itself is a benefit though getting the timings right was a bit tricky in the good old days. Most dedicated ISPs handle this nicely, though they are normally slaves to a host PC where an ‘upload’ button initiates the process.
With CircuitPython (a derivative of MicroPython), programming microcontrollers does not require going through the code-compile-flash cycle. It can be run on a number of processors, however, AVRs are not among them so this neat little library offers the next best thing. Wire-up an Atmega328P or ATmega2560 to a board like the ESP8266 that does run CircuitPython, and you can write firmware on the fly.
There is a complete tutorial on the subject thanks to [Phillip Torrone] and [Lady Ada] which includes some demo files for testing out the functionality. This opens up a lot of possibilities where OTA firmware updates for an AVR co-processor. We expect to see some keychain AVR programmers in the near future...
We all built cardboard forts when we were kids. [Paintingcook] has taken it into adulthood with a hand built cardboard wall. He and his wife leased a loft apartment. Lofts are great — one giant space to work with. Plans changed a bit when they found out they had a baby on the way. A single living, working, and sleeping space definitely wouldn’t be good for a newborn, so the couple set about separating a section of the room with a wall.
Sheetrock and steel or wood lumber would be the normal path here. They instead decided to recycle their cardboard moving boxes into a wall. The boxes were formed into box beams, which created the framework of the wall. The two pillars were boxed in and incorporated into the wall itself. The skin of the wall is a random patchwork of cardboard pieces. Most of the construction is completed with 3/8 ” screws and masking tape. Tape won’t last forever, but this is a temporary wall after all.
You might be wondering about fire hazards — sure, cardboard burns more readily than gypsum board, but the apartment is outfitted with sprinklers, which should help on this front. A few commenters on [Paintingcook’s] Reddit thread asked about formaldehyde and other gasses emitting from the cardboard. Turns out he’s an inorganic chemist by trade. He says any outgassing happens shortly after the cardboard is manufactured. It should be safe for the baby.
Cardboard is a great material to work in. You can build anything from...
If you were a kid in the 1980s you might have been lucky enough to score a Big Trak — a robotic toy you could program using a membrane keyboard to do 16 different motions. [Howard] has one, but not wanting to live with a 16-step program, he gave it a brain transplant with an Arduino and brought it on [RetroManCave’s] video blog and you can see that below.
If you want to duplicate the feat and your mom already cleaned your room to make it a craft shop, you can score one on eBay or there’s even a new replica version available, although it isn’t inexpensive. The code you need is on GitHub.
The CPU isn’t the only upgrade, as the updated Big Trak has an OLED display. [Howard] plans to add either WiFi or Bluetooth and wire the keyboard up to the onboard Arduino. [Howard] shows the inside and there is a lot of room by today’s standards. Of course, we wanted to see the original PCB, but it was nowhere to be found. Luckily, we found an image of the single-sided PCB on Wikipedia, so if you are like us, you can see it below, under the video.
There’s no wiring diagram that we could see, but from the Arduino code you can back out what the connections are to the sonar, the OLED display, and the new motor drivers for the original motors.
Oddly enough, this isn’t the first Big Trak that has made...
An Arduino and a data radio can make a great remote sensor node. Often in such situations, the hardware ends up installed somewhere hard to get to – be it in a light fitting, behind a wall, or secreted somewhere outdoors. Not places that you’d want to squeeze a cable repeatedly into while debugging.
Using the NRF24L01 chip with the Arduino is a popular choice to add wireless communications to a small project. By installing one of these radios on both the remote hardware and a local Arduino connected to the programming computer, it’s possible to remotely flash the Arduino without any physical contact whatsoever using Optiboot.
The writeup is comprehensive and covers both the required hardware setup for both ends of the operation as well as how to install the relevant bootloaders. If you’re already using the NRF24L01 in your projects, this could be the ideal solution to your programming woes. Perhaps you’re using a different platform though – like an Arduino on WiFi? Don’t worry – you can do OTA updates that way, too.
Since Autodesk’s acquisition, Eagle has been making waves in the community. The de facto standard for Open Hardware PCB design is now getting push-and-shove routing, a button that flips the board over to the back (genius!), integration with Fusion360, automated 3D renderings of components, and a bunch of other neat tools. However, according to the community, Eagle is not without its warts, and there is a desire to port those innumerable Eagle board layouts and libraries to other PCB design packages. This tool does just that.
The tool is an extension of pcb-rnd, a FOSS tool for circuit board editing, and this update massively extends support for Eagle boards and libraries. As an example, [VK5HSE] loaded up an Eagle .brd file of a transceiver, selected a pin header, and exported that component to a KiCad library. It worked the first time. For another experiment, the ever popular TV-B-Gone .brd file was exported directly to pcb-rnd. This is a mostly complete solution for Eagle to KiCad, Eagle to Autotrax, and Eagle to gEDA PCB, with a few minimal caveats relating to copper pours and silkscreen — nothing that can’t be dealt with if you’re not mindlessly using the tool.
While it must be noted that most Open Hardware projects fit inside a 80 cm2 board area, and can therefore be opened and modified with the free version of Autodesk’s Eagle that is still free despite the ignorance of the community, this is a very capable tool to turn Eagle boards and libraries into designs that can be built...