Tricking a Car Stereo to Think Your Cellphone is a Tapedeck

When you have an older vehicle there’s not a lot of options in the stock stereo department, often a CD player and tape deck is what you get. When you want to play your tunes from your mobile what do you do? Buying an adapter, or a new head unit for that matter, isn’t any fun. So why not hack it? This isn’t just a mechanical marriage of a Bluetooth dongle and an elderly stereo. Some real work went into convincing the stereo that the BT receiver was the stock tape deck.

car-stereo-logic-analyzerAttacking the outdated Cassette deck [kolonelkadat] knew that inside the maze of gears and leavers, most of it is moving around actuating switches to let the radio know that there is a tape inside and that it can switch to that input and play. Tricking the radio into thinking there is a tape inserted is handled by an Arduino. Using a logic analyzer [kolonelkadat] figured out what logic signals the original unit put out and replicating that in his Arduino code.

Audio is handled by the guts of a bluetooth speaker with the output redirected into the radio where the signal coming off the tape head normally would have been directed. Join us after the break for a couple of videos with all of the details.

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Wooden Escalator Fit for a Slinky

Our favorite mechanical master of woodworking, [Matthias Wandel], is at it again, this time making an endless staircase for a Slinky. Making an escalator out of 2×4’s and other lumber bits looks fairly easy when condensed down to a two and a half minute video. In reality a job like this requires lots of cuts, holes, and a ton of planning.

The hard part of this build seemed to be the motor arrangement. There is a sweet spot when it comes to Slinky escalator speeds. Too fast, and you’ll outpace the Slinky. Too slow, and the Slinky flies off the end of the escalator. Keeping the speed in check turned out to be a difficult task with the coarse speed control of a drill trigger. The solution was to ditch the drill and build a simple hand crank mechanism. The Slinky now can cascade down stairs as long as your arm holds out.

Join us after the break for 3 videos, the making of the escalator, a 140 step demonstration video, and a followup video (for geeks like us) explaining where the idea came from, whats wrong with the machine and possible improvements.

Thanks to [Jim Lynch] for the tip

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Everything You Wanted to Know About Oscillators

Ever wonder how a crystal oscillator works? How does that little metal can with a sliver of quartz start vibrating to produce a clock signal for just about everything we use, while doing it in the accuracy range in the parts per million and cost practically nothing?

Well [Craig] decided its about time for an in depth tutorial  that covers everything you need to know to understand, design, and construct your very own. Wrapped up in a 41 minute video, [Craig]  covers the absolute basic theories and designs, math, datasheet explanation of crystals, and even a practical example of a Pierce crystal oscillator, suitable for use in a HF transceiver. Now you can make your own for your own application no matter if you’re just trying to save a pin on your favorite micro, or making a radio transceiver.

With this wealth of knowledge, whether you are learning for the first time, or just need a refresher, you should join us after the break, kick back and check out this highly informative video.

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Talking, Foot-Pedal-Controlled Bench Probes for VirtualBench

Developing new products can be challenging during the debug and test phases, often you have your head down trying to probe the lead of some SOT23 transistor, and just when you get it, you scan your eyes up and find that your multimeter is measuring resistance and not voltage.

[Charles] had this issue compounded on his NI Virtual Instrument. It has an interface totally driven from a PC, which may or may not be in a convenient location to mouse around. Luckily NI just released an API for the 5 in one lab test station and [Charles] quickly whipped up a python wrapper which gives him ultimate control over the instrument.

Tying the script to a USB footpedal and adding some text-to-speech capabilities using google’s API [Charles] is easily able to switch from continuity to voltage to resistance and anything else he pleases with just the tap of a foot and listening to the measurements, making sure he never takes his eyes off the work which is risking a short.

Join us after the break for a quick video demonstration.

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3D Printing Helps Rekindle Old Love with an Uncommon Truck 

People may know many name and brands of cars and trucks, and there’s tons of scale models available for the average popular ones. What happens if your favorite truck is a 1960 Bucegi? You could do what [Arin] did and 3D print your own custom model.

[Arin] used to drive these machine back in his youth and it made an impression on him. In the few years of production, the 140HP V8 truck was adapted to all sorts of uses from farm trucks to military vehicles and even cranes.  The base truck and the desired configuration is modeled up in quite a bit of detail, then it’s 3D printed.

Once the printing is done the models are smoothed out using body filling primer paint, (and we imagine some fine sanding) , painted with acrylic paint, and assembled into an accurate model complete with working steering systems.

Below is a video showing assembly and painting and a second video showing off the steering system.

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Desktop CNC from Hardware Parts Really Makes the Cut

We love shop made CNC mills, so when [joekutz] tipped us off about the desktop sized CNC he just completed, we had to take a look. Each axis slides around on ball bearing drawer slides, and the machine itself is constructed with MDF and aluminum. And the results it produces are fantastic.

4950561437395360713thumbThe machine’s work area weighs in at 160*160mm with a height of 25mm. Its the table is moved around with a pair of NEMA17 motors and M8 stainless steel threaded rods. Motor control is done with a pair of Arduino’s but they also do double duty with one processing G-code while the other handles the keypad and LCD interface.

The business end is a Proxxon rotary tool whizzing up to 2000RPM, and while [joekutz] hasn’t tried it on soft metals like brass or aluminum, he has successfully cut and engraved wood, plastics and copper clad PCB material.

Be sure to join us after the break for some YouTube videos. [joe] has posted three of a planned five-part-series which aren’t linked to in the project page shown above. to see this machine in action and get a rundown how it all works

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Scrappy RGB Binary Clock From The Parts Bin

Sometimes you just want to make something, and not spend any money doing it. That’s what [Evan] had in mind when setting out to make this cool RGB LED binary Clock.

The project box is made from scrap pieces of balsa wood, with the front being a scrap of acrylic.  Multiple layers of the balsa wood were glued up to thickness and drilled to hold the LED’s, some paper was added on top then the acrylic to give everything a frosty diffused look.

LED’s are controlled by the good ‘ol 74HC595 serial to parallel shift register, and a ATTiny84 micro all set on scraps of perf board [Evan] had kicking around. Time is kept by an off the shelf RTC module and everything is point to point wired together .

Once the glue dried and a lid added, [Evan] has a colorful and fun looking 4 bit per digit binary clock that always takes us a few moments to read.