New Hackaday template coming soon. Here’s your chance to make it better!

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We’re going to be implementing a new template soon. We’ve been wanting to do this for years and it is finally happening. There are many reasons why this is necessary from site load speed to better commenting. This will give use more control over what is in our sidebar (right now I have to hand code everything into the friggin’ template!).

This is going to happen.  Help us make it awesome.

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Oscilloscope VFD repair like doing brain surgery on yourself

[Jerry Pommer] has an old Tektronix 2236 that is having some issues. Just to the right of the top corner of the screen is a VFD display that is used to show various numerical measurements. Unfortunately this has stopped working, so he made the oscilloscope probe itself in order to trouble-shoot the situation.

The entire repair process was filmed and you can see the 42-minute job embedded after the break. There’s a lot of stuff crammed inside that oscilloscope, and we see a tour of it all at the beginning of the video. Once [Jerry] gets down to business he traces the problem to a JK Flip-Flop used to feed the display. The output appears correct at first, but the clock signal is not functioning as expected. His solution is to use an MSP430 chip to replace the Flip-Flop functions.

The confidence to try this repair was sparked by [Todd Harrington's] car-stereo VFD repair video.

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Gravity bike

This bicycle has no pedals and really nothing that resembles a seat. It’s not so much a way to get around as it’s a way to get down. Down from the mountain, and down low to the pavement. This is a gravity bike built by the guys at S.I.N. Cycles.

The frame is a long triangle which stretches the wheel base to make room for the rider. After getting the layout just right and welding the frame together they added the rather unorthodox building step of pouring molten lead into the hollow frame tube. This bike is used to descend a mountain road with the force of gravity, so the extra weight will help pull it just a bit faster. There’s one thing you’ll want to make sure is working before you climb aboard — the single front brake which you’ll need when coming into the curves. Check out some ride footage on this thing in the video after the break.

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Dummy load uses gray code to adjust load in small steps

We’re not really interested in building a dummy load like this one for ourselves. But the concepts behind its design make for a nice little mental exercise as you read your way through the build description. [Pabr] wanted to build a dummy load which could be used to test a cheaply made gas generator. He wanted it to be as simple as possible, while providing a range of different loads. What he came up with is this monotonically adjustable load tester which uses gray codes for switching.

The video after the break does a good job of explaining the motivation for the design. Grey coding ensures that just one bit changes at a time. The example he uses to show the importance of this is when binary code transitions from 7 (0b0111) to 8 (0b1000). Three digits have been turned off and one has been turned on. Since he’s using light bulbs for his load this will turn off 700 Watts and then switch on 800W. That sudden jump in power draw can cause all kinds of problems with the generator’s engine. But the system he wired up will ensure that each flip of a switch moves in smaller steps.

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Exploiting DFU mode to snag a copy of firmware upgrades

[Travis Goodspeed] continues his work at educating the masses on how to reverse engineer closed hardware devices. This time around he’s showing us how to exploit the Device Firmware Updates protocol in order to get your hands on firmware images. It’s a relatively easy technique that uses a man-in-the-middle attack to dump the firmware image directly to a terminal window. This way you can get down to the nitty-gritty of decompiling and hex editing as quickly as possible.

For this hack he used his Facedancer board. We first saw the hardware used to emulate a USB device, allowing the user to send USB commands via software. Now it’s being used to emulate your victim hardware’s DFU mode. This is done by supplying the vendorID and productID of the victim, then pushing the firmware update as supplied by the manufacturer. In most cases this shouldn’t even require you to have the victim hardware on hand.

Teens pulled over while driving their wooden roadster

From this view we would think the handmade wooden roadster (translated) was street legal. But it’s missing a few items that are required to take it out on the highway. The teenagers that built it were pulled over the other night (translated) and cited for driving without a speedometer or side indicator lights.

The image above shows the mark II of their design. Sadly they crashed the first version, which gave them a chance to overhaul the entire design. Now they have a proper frame which was welded from steel square tube. It’s got an impressive rack and pinion steering system and shock absorbing suspension in the front and rear. A dirt bike engine mounted behind the seats drives the rear wheels via a chain. They’ve used an Arduino to add turn signals, and have headlights for night driving.

[Gerrit] sent in the tip on this one and he figures that with an Arduino already being used in the vehicle it should be a quick fix to add a speedometer and get back on the road.

Hackaday AMA happening right now at Reddit.

Our AMA is live right now.  Come ask us questions. You can ask here in our comments too, but frankly the Reddit system is better for at length nested discussion.

Items to be discussed:

-how to submit your story to hackaday

-our new template coming soon

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