Adding heat sinks to a Raspberry Pi

[Michael Dornisch] was surprised to find that the main processor of the Raspberry Pi reaches about 56 degrees Celsius (about 133 degrees F) while streaming video over the network. He thought it might help the longevity of the device if he was able to cool things off a bit. But why stop with just the processor? He added heat sinks to the SoC, Ethernet/USB chip, and voltage regulator.

From his parts bin he grabbed a small heat sink that was probably used on a graphics card. After measuring the three chips with his digital calipers he cut out the footprint he needed, resulting in three smaller heat sinks. We didn’t realize that thermal compound has enough gripping power to hold the sinks in place without any mechanical fastener, but apparently it does. [Michael] mentions that it’s possible to use other adhesives, like JB Weld. What’s important is that you use something (ie: thermal compound or a liquid adhesive) to prevent any air gap from coming between the chip surface and the aluminum.

He measured the result as a 17.3 degree C (31 degree F) drop in temperature. We looked around and it seems there’s no internal temperature sensor on the Broadcom chip so these surface readings will have to suffice. Do you think this will prolong the life of the board if it is used regularly to play back high quality video? We already know that these temperatures are within the specifications for the hardware.

[Thanks Simon]

Building a 1300 lumen bike light

[Brainiac27] isn’t going to let the absence of sun prevent him from biking. He has no trouble lighting his path with this 1300 Lumen bike light he built.

The light source is a 3-up star by Cree. It puts off a lot of light, but also generates quite a bit of heat which is the reason for that large heat sink. It is meant to be used with a CPU but works well for this purpose thanks to the adhesive thermal paste used to unite the two parts.

The mounting bracket is a custom job, bent from 1″ by 1/8″ aluminum bar. [Brainiac27] had some issues with length the first time he tried making it. For his second attempt he started with an overly long piece, made the bends from the center out, and only made cuts once the bends were all completed. The bracket makes it easy to mount to his bike, with the battery stored in a bike bottle and a remote switch (with attaches to the jack you can see on the project box above) hidden underneath one of the brake hoods.

The intensity of this light nearly doubles one of our other favorites.

Hackaday Links: November 24, 2011

Finally an Arduino shield that does nothing

The folks at Evil Mad Scientist labs have finally created the Googly Eye Shield for Arduinos. With it’s pass-through .100 headers, it adds googly eyes to your Arduino projects. Of course, instead of in addition to the googly eyes you could add a breadboard, making it somewhat useful. A million fake internet points goes to the first person to implement Xeyes on this thing.

Phat beats from kids toys

[Ville] couldn’t afford an Akai MPC for laying down some beats. Wanting a real tactile interface, he hacked this kid’s toy. It’s just an RCA cable attached to the tiny chip inside the toy. The new line out goes to his mixers where he does some pretty impressive stuff.

Mona Lisa is Vigo the Carpathian

What did we just say about real-life Xeyes? [Geert] just made a print of the Mona Lisa follow you around the room with her eyes (Dutch, translation). The build is a pair of servos and a DIY motion capture app running on a laptop. Now we need to find a print of Vigo…

Quantifying heat sink efficiencies

[Mike] is an experimenter at heart. He was wondering about the efficiency of small, clip-on heat sinks versus the ones we use to defrost frozen food. The results are exactly as you would expect, but he did find something interesting – his experimental technique didn’t find much of a difference between thermal paste/grease/pads and no thermally conductive material.

Mini-fig sized R/C LEGO car

The guys at took a car from a LEGO set and made it remote control. The drive train and steering both use servos controlled by the smallest 3-channel receiver they could find.

Hackaday Links: October 28th, 2011

An accidental radial engine

Hack A Day’s very own [Jeremy Cook] was trying to figure out how to push four ‘arms’ out one at a time. What he came up with is a very nice model of a radial engine. Everything was cut on a CNC router and a motor from an air freshener provides the power.

Using a candle to produce light

[Chris] sent in his Candela Amplifier. It’s a Pentium 4 heat sink with a very bright Cree Xlamp LED attached to the base. A bunch of Peltier thermoelectric units are attached to the underside of the heat sink. Put the whole thing on top of a candle, and you can light a room. With a candle. Oh, he’s selling these, by the way.

Objectification and video games?!

We really feel sorry for our lady readers. Guys have so many choices for Halloween costumes, but just about every costume available for women can be reduced to, “Sexy [noun].” Whelp, here’s the Sexy Game Boy, just in time for Halloween. [kazmataz] gets a few bonus points because she went with the DMG-01. It’s better than Sexy Chewbacca, so she’s got that going.

Prototypable 32-bit uCs

[Ng Yong Han] wrote in to tell us about some newish 32-bit PICs that are floating around. The datasheet for the PIC32MX1xx/2xx chips is pretty interesting – USB support and an audio and graphics interface. Oh, they come in PDIPs for ease of prototyping as well. We haven’t seen much from the PIC microcontroller faction recently (Atmel is winning the holy war, it seems). Anybody feel like building something with these?

Makerbot dual extruder

[Lomo] at TU-Berlin is taking a class in rapid prototyping. He built a second print head for his department’s Makerbot Cupcake with a few other students. The result are pretty impressive, although from what we’ve seen, it’s generating the G-code that’s a pain in the butt.

Chill your phone for longer battery life?

The first specs we look at when choosing a cellphone are the battery life numbers. We know that eventually we’re going to see performance loss, and [Dr. West] wanted to see if there’s a way to delay the inevitable. What he found is that ambient temperature affects the battery throughout its life. He set out to build a phone chiller to slow the degradation of the battery.

The research that he points to shows that at room temperature, a Lithium battery will lose 20% of its capacity each year. This seems like a dubious number so do share links to studies that state otherwise in the comments. Whether that 20% is right or not, the point is that cooling the battery will preserve it. With that in mind, [Dr. West] put together a pod that uses a peltier cooler and a heat sink to host his Blackberry while he sleeps. He figures he can reduce the capacity lost per year from 20% down to 14%. This of course comes at the expense of running that cooler every night (in addition to charging the phone when it needs it). But perhaps this solution will spark an idea that leads to a better one.

CPU as a heat sink

We’ve noticed that wireless routers pump out a bunch of heat. [Jernej Kranjec] wanted to make sure that he didn’t fry it once he started adding more load to his router using OpenWRT. What he came up with is the idea of using an old CPU as a passive heat sink. He applied a bit of thermal paste to the center and some super glue to the corners. You can see the finished product is an old AMD chip adhered “dead bug” style to the stock processor. We’d bet it’s not very efficient compared to an aluminum or copper heat sink, but it normally would have no help in shedding those extra degrees.

Generate electricity with a candle

What you see above is a generator that converts heat to electricity. [Reukpower’s] thermoelectric lamp is one of those hacks that makes you scratch your head even though you understand why it should work. The heart of the system uses a Peltier cool, just like the thermoelectric solar generator. When there is a temperature differential from one side of the Peltier to the other a small current is generated.

In this case a candle heats one side and a heat sink cools the other. The tiny voltage picked up from the Peltier’s contacts is then boosted using a joule thief. We’ve seen LEDs powered with a joule thief before, benefiting from their own low power consumption. In this case, the boost circuit is scavenged from an emergency phone charger and probably achieves higher efficiency than if he had built it himself.