DIY Bike Brake Light And Turn Signals

September 14, 2014 by Rich Bremer 65 Comments

If you ever take your bike out and share the road with large automobiles, you know that sometimes it can get a little hairy. As a biker, you will stand no chance in a collision with a vehicle. Communicating your intentions, i.e. turning and braking, can certainly reduce your risk of getting in an accident. [Mike] didn’t like the traditional idea of taking a hand off the handlebars in order to signal to traffic so he did something about it, he built turn signals and a brake light for his bike.

The business end of this project is the rear-facing light bar mounted under the rider’s seat. It is made from Radio Shack project boxes and mounted to an off-the-shelf L bracket. A bunch of LEDs were installed in the project boxes, the yellow turn signal LEDs are arranged in the shape of arrows and the red brake light LEDs are in an oval. Inside the project boxes you will find the 9v battery that powers the circuit and also a breadboard that is home to the circuits responsible for blinking the turn signals.

Check out the switch assembly that is mounted to the handle bars. It was built using an old reflector bracket which was already the correct size to mount to handle bars. As you would expect, there is a toggle switch for turning the turn signals on and off. A little bit more interesting is the brake switch. It is a hinge-lever style limit switch and positioned in a manner such that it is activated when the brake lever is pulled. There is no additional thought or effort required on the cyclist’s part!

Something that is certainly not expected on the switch assembly is the headphone jack. [Mike] likes to listen to music while he rides and a cord dangling around from a backpack or bike bag gets in the way. On the rear light bar, there is a headphone jack that allows an MP3 player to be plugged into. The audio signals travel up the same CAT5 cord used for the turn and brake signals. This allows only a short run of headphone cable from the handlebars to [Mike’s] ears.

THP Quarterfinalist: Hypoglycaemia

September 14, 2014 by Brian Benchoff 15 Comments

For somewhat obvious reasons, there aren’t many medical hacks making their way to the quarterfinal selection of The Hackaday Prize. One exception to this is [Thomas]’ Hypoglycaemia Alert System, a Bluetooth device that detects low blood sugar in sleeping diabetics and calls for help.

This isn’t the only blood glucose monitor that made it to the quarterfinals of The Hackaday Prize. [John Costik] reverse engineered a continuous glucose monitor for his Type 1 son (we also did a hacker bio on him). This project has a slightly different scope and doesn’t rely on pre-existing blood glucose sensors. In fact, it doesn’t detect glucose at all. Instead, it uses humidity and temperature sensors to detect the heavy sweating that often occurs with low blood glucose levels.

This hypoglycaemia monitor is meant to be worn by a user at night. Glucose levels can drop while sleeping, and if they drop too low blood sugar can result in death. When the monitor detects the symptoms of low blood glucose, it connects to a smartphone through a Bluetooth link and sends an SMS alert to phone numbers in the contact list. Whoever receives this message will then try to wake the potentially unresponsive diabetic, and failing that, would put some cake frosting under their gums (Seriously. Ask a police officer/EMT for cake frosting. The good ones have some).

[Thomas] is well on his way to a functional device despite having a few problems with his enclosure. Right now he’s working on the Bluetooth comms part of the build, and we hope a complete, working device is right around the corner.

The project featured in this post is a semifinalist in The Hackaday Prize.

Persistence Of Vision Clock On A Propeller

September 14, 2014 by Bryan Cockfield 1 Comment

If you have a spare DC motor, a PIC16F84A microcontroller, and a lot of patience, then [Jon] has a great guide for building a persistence of vision clock that is sure to brighten up any room. For those who are unfamiliar with this type of clock, the principle is simple: a “propeller” with LEDs spins, and at just the right moment the LEDs turn on and display the time.

We’ve featured persistence of vision projects before (many times), and have even featured [Jon]’s older clocks, but the thing that makes this POV clock different is the detail of the project log. [Jon] wasn’t satisfied with the documentation of existing projects, and went through great pains to write up absolutely everything about his clock. The project log goes through four major versions of the hardware and goes into great depth about the software as well, making it easy for anyone to recreate this robust clock.

As for the clock itself, the final revision of the hardware has a PCB for all of the components, and uses a PC fan motor to spin the propeller. Power delivery eliminates slip rings or brushes in favor of wireless power transfer, which is an impressive feat on its own. Indeed, the quality of the clock is only surpassed by the extreme level of detail!

Energia On The CC3200

September 13, 2014 by Eric Evenchick 13 Comments

If you’re looking to connect things to the internet, with the goal of building some sort of “Internet of Things,” the new CC3200 chip from TI is an interesting option. Now you can get started quickly with the Energia development environment for the CC3200.

We discussed the CC3200 previously on Hackaday. The chip gives you an ARM Cortex M4 processor with a built-in WiFi stack and radio. It supports things like web servers and SSL out of the box.

Energia is an Arduino-like development environment for TI chips. It makes writing firmware for these devices easier, since a lot of the work is already done. The collection of libraries aids in getting prototypes running quickly. You can even debug Energia sketches using TI’s fully featured IDE.

With this new release of Energia, the existing Energia WiFi library supports the built-in WiFi radio on the CC3200. This should make prototyping of WiFi devices easier, and cheaper since the CC3200 Launchpad retails for $30.

THP Hacker Bio: AKA

September 13, 2014 by Brian Benchoff 5 Comments

Thermal imaging cameras are the new hotness when it comes building DIY tools that are much less expensive than their commercial counterparts. [Mike Harrison] built a very high-resolution version from Flir’s Lepton module, but an IR temperature sensor and a servo can also create a decent image. [AKA] played around with some of these thermal imaging modules, but found them a little hard to interface. Panasonic’s Grid-EYE module, however is reasonably cheap as far as thermal imaging devices go, and can be read over an I2C bus.

[AKA]’s entry for the Hackaday Prize, the GRID-EYE Thermal Camera is one of two Prize entries that survived the great culling and made it into the quarterfinalist round. [AKA] was kind enough to sit down and do a short little interview/bio with us, available below.

Continue reading “THP Hacker Bio: AKA” →

Tesla Model S Battery Teardown

September 13, 2014 by Adam Fabio 84 Comments

Tesla Motors club user [wk057], a Tesla model S owner himself, wants to build an awesome solar storage system. He’s purchased a battery pack from a salvaged Tesla Model S, and is tearing it down. Thankfully he’s posting pictures for everyone to follow along at home. The closest thing we’ve seen to this was [Charles] tearing into a Ford Fusion battery. While the Ford battery is NiMH, the Tesla is a completely different animal. Comprised of over 7000 individual lithium-ion cells in 16 modules, the Tesla battery pack packs a punch. It’s rated capacity is 85kWh at 400VDC.

[wk057] found each cell connected by a thin wire to the module buses. These wires act as cell level fuses, contributing to the overall safety of the pack. He also found the water cooling loops were still charged with coolant, under a bit of pressure. [wk057] scanned and uploaded high res images of the Tesla battery management system PCBs (large image link). It is a bit difficult to read the individual part numbers due the conformal coating on the boards.

A second forum link shows images of [wk057] pulling the modules out of the pack. To do this he had to chip away the pack’s spine, which consisted of a 2/0 gauge wire potted in some sort of RTV rubber compound.

We’re sure Tesla doesn’t support hackers using their packs to power houses. Ironically this is exactly the sort of thing Elon Musk is working on over at Solar City.

Sweet Guitar Practice Amp Is A Literal Work Of Art

September 13, 2014 by Rich Bremer 19 Comments

Check out this ~~odd~~ different looking guitar practice amp. It looks like a professionally manufactured product but it certainly is not. [Bradley] made it himself, not just a little bit of it either, all of it.

One of the first things you notice is the quilted maple wood grain of the case. There is no veneer here, this started out as a solid maple block. The front radius was shaped and the recesses for the control knobs and input jack were bored out using a forstner bit. The case was sanded smooth and several coats of high gloss tung oil was rubbed on to give the wood a perfect finish. A small piece of grill cloth protects the speaker while adding a little more class to the amp. The bottom of the case is actually a cover for a computer hard drive. A rectangular hole cut in the hard drive cover makes way for a 9 volt battery compartment.

There are two control potentiometers, one for volume and one for gain. Any old knobs wouldn’t do for this project. [Bradley] knurled and turned his own aluminum knobs and they look awesome! The units power is turned on when the guitar cord is plugged in. An LED not only indicates that the power is on but it also gets brighter with the volume input from the guitar. The LED also pulses if two strings are out of tune with each other giving the guitarist an opportunity to tune one of the strings until the LED stops pulsing. When it is time for some private jamming headphones can be plugged into the amp and doing so cuts power to the speaker.

The electronic circuitry is [Bradley’s] design also, but unfortunately he doesn’t share the schematic. I suppose he wants to keep his amp one-of-a-kind.