Grinding a Bicycle Crank for Power Analysis

For [Mark] and [Brian]’s final project for [Bruce Land]’s ECE class at Cornell, they decided to replicate a commercial product. It’s a dashboard for a bicycle that displays distance, cadence, speed, and the power being generated by the cyclist. Computing distance, cadence and speed is pretty easy, but calculating power is another matter entirely.

The guys are using an ATMega1284 to drive an LCD, listen in on some Hall Effect sensors, and do a few calculations. That takes care of measuring everything except power. A quick search of relevant intellectual property gave then the idea of measuring torque at the pedal crank. For that, [Mark] and [Brian] are using a strain gauge on a pedal crank, carefully modified to be stiff enough to work, but flexible enough to measure.

A custom board was constructed for the pedal crank that measures a strain gauge and sends the measurements through a wireless connection to the rest of the bicycle dashboard. It works, and the measurements in the classroom show [Brian] is generating about 450 W when pedaling at 33 mph.

Video below.

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Capacitive Garage Door Opener Hides Behind Your Dash

[Pyrow] wanted to upgrade his garage door opener remote. It worked just fine, but changing those tiny batteries out can be an inconvenience. Plus, the remote control was taking up valuable storage space and would always rattle around while driving. [Pyrow] decided to make use of an Omron E2K-F10MC2 capacitive touch sensor to fix these issues.

[Pyrow’s] circuit still makes use of the original remote control. He just added some of his own components to get it to do what he wanted. The circuit is powered by the car’s battery, so it never needs a battery replacement. The circuit is protected with a fuse and the power is regulated to prevent electrical spikes from burning up the original remote control. The actual circuit is pretty simple and uses mostly discrete components. It’s all soldered onto proto board to keep it together. He only had to solder to three places on the original remote control in order to provide power and simulate a button press.

Next, [Pyrow] took his dash apart. He used double-sided tape to attach the touch sensor to the back of the dash.  After securing the electronics in place with tape, he now has a working hidden garage door opener. Full schematics are available in the writeup linked above. Also, be sure to watch the demonstration video below.

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THP Entry: Digital Gauges For Everything Automotive

DDAQ

Way back in 2007, someone on a VW TDI forum came up with a new boost gauge project. At the time, it was a remarkable feat of engineering, capable of displaying the manifold pressure on a tiny OLED on the dashboard. No project has yet reached this caliber since. [Digital Corpus] is revisiting the project, making it his own, adding a few upgrades, and entering it into the Hackaday Prize.

The D-DAQ, as [Digital] calls his new project is using an absolute pressure sensor, unlike its predecessor. This gives the turbo gauge a much larger range than the original project, and also allows the D-DAQ to measure partial vacuum in non-diesel turbos.

In addition, the D-DAQ has a much wider scope than the original project, and as such will function as much more than a simple boost gauge. [Digital] sees the D-DAQ as being a complete performance monitor and logger, capable of tracking the exhaust gas temperature, battery voltage, and just about anything else with 10 analog pins. Data will be saved to a MicroSD card, and instead of a single display, the D-DAQ will feature three 160×128 OLEDs.

It’s certainly not what you’d expect from a Hackaday Prize entry, but with these features, it’s very possible the D-DAQ could be a successful product


SpaceWrencherThe project featured in this post is an entry in The Hackaday Prize. Build something awesome and win a trip to space or hundreds of other prizes.

Garage Clicker Dashboard Integration

garagedoor-opener-in-dash

Vehicles with the highest level of trim package sometimes come with the ability to learn garage door opener codes. Less costly offerings lack that feature as well as others bells and whistles, leaving blank plates where fancy buttons would have been. [JiggMcFigg] makes the best of this situation by gutting his garage remote and hiding it behind a button blank.

One thing that raised an eyebrow is the coin cell battery holder you can make out on the size-check image shown to the left. But really, these remotes must drain their batteries at a rate nearly the same as an unused battery so why complicate the hack? A holder was soldered onto the board, and jumper wires were soldered to the push button added to the blank plate. This type of utilitarian button is much more satisfying to use than those fancy-pants silk-screen molded-plastic types anyway!

Of course you could go the other way with this hack. [JiggMcFigg] started out with the problem of losing the remotes in the mess of the car. You could retrofit it with a huge button to make it harder to misplace.

Jeep dashboard display turned into a desk clock

jeep-dash-display-clock

This display is easily recognizable by the buttons and the outline of a vehicle to the left. It’s a Vehicle Information Center (VIC) from a Jeep Grand Cherokee. [Florlayamp] discovered a row of the vehicles in a junkyard, all with the displays still intact. He grabbed one and turned the VIC into a desk clock. What would you pay for such a fine piece of used electronic hardware? How about six bucks? Yeah!

Getting it running couldn’t be simpler. It’s all set up to be programmed and run on it’s own. A bit of searching around turned up a schematic to figure out which wires are for power. It took some time to figure it out, but the thing draws about 2A so finding a worthy wall wart was a must.

Now that he was sure it would work [Florlayamp] started on the case build. It’s poplar with quarter round to frame the display. On the back you’ll find a single rocker switch.

Usually we see the opposite of this, adding displays to the dashboard instead of salvaging them.

 

ODB-II hacking using an Android tablet

What a strange message to read on the digital dashboard display of your car. This is proof that [Kristoffer Smith] was able to control the ODB-II bus on his Eagle Grand Cherokee.

He’s not just doing this for the heck of it. It stems from his goal of adding an Android tablet on the dashboard which has been a popular hack as of late. This left [Kristoffer] with steering wheel controls that did nothing. They originally operated the radio, so he set out to make them control the tablet.

He had seen an Arduino used to control the CAN bus, but decided to go a different route. He grabbed a USB CAN bus interface for around $25. The first order of business was to use it with his computer to sniff the data available. From there he was able to decode the traffic and figure out the commands he needed to monitor. The last piece of the puzzle was to write his own Android code to watch for and react to the steering wheel buttons. You can check out the code at his repository and see the demo after the break.

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Adapting the Nexus 7 for a double DIN car dashboard opening

It turns out that the Nexus 7 Android tablet is the perfect size to fit in a double DIN opening. DIN is the form factor of a single CD head unit for an automobile. Many models have room for a double DIN, which is defined as 4″ high by 7″ wide. Once [Meta James] figured out that the dashboard bezel for his Subaru framed the Nexus 7 perfectly he set out to fabricate the mounting system for an in-dash tablet installation.

Unlike a lot of these dashboard tablet installs, [James] didn’t need any Bondo, sanding, or painting to get things to look right. Like we mentioned, the bezel is a perfect fit so his alterations are hidden behind the tablet itself. He removed the stock head unit and ordered a DIN adapter kit to get the black bracket plate seen above. He built an acrylic box the same size as a double DIN head unit, then mounted the plates to the sides and a Nexus 7 case to the front. This holds the tablet in firmly, lets him mount the entire assembly using the factory mounting points, and leaves plenty of room for the cabling that connects the device to the car. Since he already had a hands-free phone system he just uses that to amplify the audio fed to it via Bluetooth.

[via Reddit]