Adorable Homebrew Waveform Generator

November 2, 2013 by 25 Comments

waveform

For want of new test equipment, or simply a project, [Enzo] decided he would take a shot at creating his own waveform generator*. Not only is it a great project, it’s also a decent piece of test equipment, with proper signal conditioning, a nice front panel, and a built-in wall transformer.

The guts of [Enzo]’s waveform generator is an AD9833 programmable waveform generator, a neat little chip that can output square and triangle waves fro 0.1 Hz to 3.2 MHz and sine waves from 0.1 Hz to 1.6 MHz. [Enzo] is controlling this chip with a PIC16 microcontroller, with a whole bunch of analog circuitry between the digital domain and the BNC connector on the front panel.

The waveform generator is controlled by a suite of dials and switches on the front panel, giving [Enzo] complete control over his new tool.

* Here’s a Google translation, but good luck with that. Just… get Chrome or something.

Perfect PCBs With An Inkjet Printer

November 2, 2013 by 69 Comments

Instead of mucking about fabbing PCBs with the toner transfer method, or making masks for photosensitive boards, the holy grail of at-home circuit board manufacturing is a direct inkjet-to-etch method. [Don] isn’t quite there yet, but his method of producing circuit boards at home is one of the easiest we’ve ever seen.

[Don]’s boards begin by taking the output from Eagle and printing them with an Epson Artisan 50 inkjet printer. By sticking a piece of cardstock in the printer before the copper board, he’s able to precisely align the traces and pads onto the copper board.

When the board comes out of the printer, it’s only covered in ink. While some specialty inks are enough of an etch resist, [Don] comes up with a clever way to make sure acid doesn’t eat away copper in the needed places – he simply dusts on toner from a copier or laser printer, blows off the excess, and bakes the entire board in a toaster oven.

The result, seen above, are perfect traces on a circuit board without the need for ironing sheets of photo paper onto copper boards.

As far as the, “why didn’t someone think of this sooner” ideas go, this one is at the top. [Don] says the method should work  on sheets of aluminum for printing solder paste masks. Impressive work, and now the only thing left to do is getting two-layer boards down pat. For more direct to copper printing check out the hacks we’ve covered in years past.

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A Nightmare On CNC Street

November 2, 2013 by 43 Comments

[James Dressman] emailed us about his two-year journey of getting a large CNC machine running in his home. He doesn’t currently have a webpage, however his story was so incredible that we just had to feature it.   [James] started by doing plenty of research online, and ordering a new CNC. The real fun started when he opened up a wall to fit the 2300 pound monster into his home. [James] found so much insect and water damage that he ended up rebuilding the entire rear half of his home.

Once the CNC was safely set up, the fun still wasn’t over. Not all family members are keen on having an industrial machine tool in the house. In [James’] case it was the smell of way oil that drove his wife nuts. This was all before spindle problems with the tool itself began to rear their ugly head. Illness and family tragedy put everything on hold for several months, however once [James] strength returned, he attacked the problems with renewed vigor. It was a long and winding road, but he now has a fully functional CNC.

But don’t just take our word for it. Continue after the break to see his photo album and to hear James tell the story in his own words.

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Arduino Keypad Door Automation

November 1, 2013 by 45 Comments

arduino door pad

[Andrea] just sent us this great student hack he made for his room. He’s constructed an Arduino keypad door lock — without using any proper fastening hardware!

The entire build is made out of scrap parts he had lying around: some DVD’s, a bit of wood, an allen key, a motor and belt from a broken printer, an old hard drive enclosure, and a few power supplies. As you can see the entire setup is held up rather artistically using good old duct tape.

The system auto-locks after 5 seconds, and just in case, [Andrea] has hard-coded in a few safety codes into the firmware to allow him to forcefully open the door — you know, if it malfunctions or something. Not overly confident in his code, he also has it reset every 5 minutes of idling to safeguard against potential memory leaks — probably a good idea! All in all it’s a very cool build, and we have to give him props for not damaging the door to mount it! Down the road he’s also planning on adding a knock sensor using the small speaker that is already part of the circuit, because, why not?

Stick around after the break to see this magnificent contraption that would make Red Green proud.

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Deconstructing Apollo Flight Hardware

November 1, 2013 by 17 Comments

[Fran] has been researching the Saturn V Launch Vehicle Digital Computer – the computer that flew all the Apollo flights into orbit and onwards towards the moon – for a while now. Even though she’s prodded parts of the LVDC with x-rays and multimeters, this is the first time she’s committed to a little destructive testing.

After [Fran] took a flight-ready LVDC spare to the dentist’s office for x-raying and did an amazing amount of research on this artifact from the digital past, there was only so much she could learn without prying apart a few of these small, strange chip packages. Not wanting to destroy her vintage LVDC board, she somehow found another LVDC board for destructive reverse engineering.

This new circuit board was a bit different from the piece in her collection. Instead of the chip leads being soldered, these were welded on, much to the chagrin of [Fran] and her desoldering attempts. After removing one of these chips from the board, she discovered they were potted making any visual inspection a little difficult.

While [Fran]’s attempts at reverse engineering the computer for a Saturn V were a bit unsuccessful, we’ve got to hand it to her for getting this far; it’s very, very likely the tech behind the LVDC was descended from ICBMs and would thus be classified. Documenting the other computer used in every Apollo launch is an impressive feat on its own, and reverse engineering it from actual hardware, well, we can’t think of anything cooler.

Heathkit Clock Updated With A PIC32 And GPS

November 1, 2013 by 46 Comments

heathkit-clock

One of [Bob’s] most treasured possessions is a Heathkit alarm clock he put together as a kid. Over the years he’s noticed a few problems with his clock. There isn’t a battery backup, so it resets when the power goes out. Setting the time and alarm is also a forward only affair – so stepping the clock back an hour for daylight savings time means holding down the buttons while the clock scrolls through 23 hours. [Bob] decided to modify his clock with a few modern parts. While the easiest method may have been to gut the clock, that wouldn’t preserve all those classic Heathkit parts. What [Bob] did in essence is to add a PIC32 co-processor to the system.

Like many clocks in the 70’s and 80’s, the Heathkit alarm clock was based upon the National Semiconductor MM5316 Digital Alarm Clock chip. The MM5316 operates at 8 – 22 volts, so it couldn’t directly interface with the 3.3V (5V tolerant)  PIC32 I/O pins. On PIC’s the input side, [Bob] used a couple of analog multiplexer chips. The PIC can scan the individual elements of the clock’s display. On the PIC’s output side, he used a couple of analog switches to control the ‘Fast’, ‘Slow’, and ‘Display Alarm/Time’ buttons.

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