DIY Pringles Can Speaker

pringles can speaker

Looking for a fun weekend project? How about making your own speaker from scratch using some very basic materials?

[Go Repairs] makes a bunch of how-to videos for Instructables in a style very reminiscent of the classic Art Attack from the 90′s — very clear, concise and he’s even got the accent!

The project requires only what you see in the photo above. The lid forms a simple plastic cone of the speaker, the magnets are the core, and using some paper, tape, and enamelled wire a very basic voice coil is constructed. Don’t expect amazing sound quality out of it, but it certainly looks like a fun project for junior hackers as it requires no fancy tools or equipment!

Stick around after the break to watch the video — does it remind you of Art Attack also?

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Recreate a PCB with a Scanner and Inkscape

turnsig

[John] has managed to replace a broken turn signal PCB by scanning it and converting to Gerber format. [John] purchased a Triumph Spitfire with toggle switch wired up for turn signal control. The “official” replacement part worked better than the toggle switch, but it didn’t cancel after turning. He was able to get the original switch, only to find it had a hole completely burned through the phenolic board. This isn’t completely surprising, as Triumph used a Lucas Industries electrical system. As anyone who has owned a car with a Lucas “prince of darkness” electrical system will tell you, Lucas systems were not known for quality. A quick Google search brings up plenty of pages attesting to this.

Phenolic resin/paper was a common early PCB material.  The FR-4 fiberglass boards most commonly used today could be considered descendants of FR-1 and FR-2 phenolic. (The FR in this case stands for Fiber Reinforced). The standardization worked in [John's] favor, as his burned board was 31 mils thick, which is still a standard PCB thickness. Re-creating an odd sized board such as this isn’t a hard job. It would however mean spending quite a bit of time with a ruler and a caliper. Rather than spend all that time measuring and re-drawing, [John] scanned his PCB on a flatbed scanner. He used graph paper as a background to verify the image wasn’t being stretched or skewed.

[John] brought his scan into inkscape, and traced both the outline and copper areas. The outline and copper had to be exported as two separate files, so he added corner marks outside the board outline as fiducials.  He then used pstoedit to convert inkscape’s eps output files to gEDA pcb format. The two files were rejoined in gEDA. From there [John] exported a Gerber, and ran it on his home PCB milling machine.  The results look good. [John] plans to make another revision of the board from a professional PCB house with vias to hold the copper to the substrate.

Peltier Joule Thief Power Supply

Peltier Joule Thief Power Supply

[Steven] manages to power an LED for 15 minutes using hot and cold water as a battery. He does this using the thermoelectric effect also known as the Seebeck effect, Peltier effect or Thomson effect. This isn’t particularly new; in fact there are commercial products that you can use to charge a cell phone using a small campfire or internal burner that works on the same principle.

What is interesting about [Steven’s] device is that he uses a salvaged Peltier device not meant for generating electricity, coupled with a home built joule thief circuit. In the video he describes how the joule thief functions and powers the LED using the small voltage generated by the Peltier device. The energy for the thermoelectric effect is conducted from a hot water bath through aluminum plates, through the positive and negative sides of the Peltier device, through more aluminum plates and finally into a cold water bath. As the heat energy transfers through the Peltier device a small electric current is generated and flows in two small wires coming out the side of the device.  The energy generated by the Peltier device is stored in the joule thief and periodically dumped at a voltage high enough to forward bias the LED “on” for a brief moment. Technically the LED is flashing but at a frequency too high for our eyes to see. As the hot water bath cools, the LED goes from very bright, to dim, to off in about 15 minutes.

Not a very practical power supply but still quite the parlor trick. He wraps up the tutorial specifying that a TEG thermoelectric generator would be a much better choice for generating power and can handle much higher temperatures. You can watch the video after the break.

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Diagnose and Repair a Yaesu FT-7800 Ham Radio

Yaesu FT-7800 Ham Radio

[Alan Wolke] aka [w2aew] was challenged to repair a friends Yaesu FT-7800 ham radio. This radio operates on two ham bands, 2 m VHF and 70 cm UHF. The complaint was that the 2 m side was not working but the 70 cm was transmitting fine. Alan started by verifying the complaint using a Bird watt meter with a 50 watt slug and terminating the signal into a 50 W dummy load. [Allen’s] bird meter is the type that has an RF sampler that can be connected to an oscilloscope for added signal viewing and validation.

After verifying that the radio was not working as described, Alan starts by glancing over the circuit board to look for any obvious damage. He then walks us through a block diagram as well as a circuit diagram of the FT-7800 radio before stepping us through the troubleshooting and diagnostics of radio repair. Even when he realizes he might have found the problem he still steps us through the remainder of his diagnostics. The skills and knowledge that Alan shares is extremely valuable to anybody looking to repair radios.

Spoiler alert. At the end of the first video he determines that the pin diodes near the final VHF output were bad. In the second video he reveals that he could no longer source these bad components. Through some clever evaluation of a more current Yaesu radio, [Allen] was able to find suitable replacement components. Lesson two ends with some surface mount solder rework tips as well as testing that the repair was successful.

And just in case you don’t know what a pin diode is, or is used for, Alan shares a third video covering just what this component is and does in a radio. You can follow the jump to watch all three videos.

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Build Your Own Desoldering Station on the Cheap

Desoldering Station on the Cheap

[Sable Wolf] tipped us off to his DYI desoldering station for under $70. We know we have seen this conversion before, but it hasn’t been featured on Hack a Day. [Sable Wolf’s] hack is unique and has added features that make building, cleaning and the overall longevity sounder. However, some kind of sound deadening housing would have to be built around the pump as it seemed uncomfortably loud in the video.

Some Chinese made desoldering stations are getting quite cheap so maybe it’s not worth the effort unless you can salvage more components for the build. Thanks to [Sable Wolf’s] detailed blog you can browse through his BOM and scrounge up the majority of these items from your salvage bins. A cheap but reliable desoldering station would be an extremely handy tool to have on your bench.

This is much safer than desoldering with a candle or using fire as featured in the past, and is kind of a flip around on the SMD hot air pencil hack.

Follow long after the break to watch the video of the desoldering station in action.

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KiCad video series: from concept to manufacture

Many of our readers took the habit of using Eagle to design their PCBs. Even if you’ll find plenty of support for this software as well as a lot of parts libraries, the software comes with limitations. The useable board area is limited to 4×3.2 inches, only two signal layers can be used and more importantly the schematics editor can only create one sheet. On the other side, some of you may already know KiCad, a free open source and unrestricted schematics and layout software. [Chris] just tipped us of a video series he made, showing people how to design and build their very first PCB using this software. It’s a simple 555 circuit, but goes through all the steps necessary to design a PCB that costs only $5 through OSHpark… and will blink by the end. All the videos are also embedded after the break.

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DIY Doggy Doorbell

doggy doorbell

Is your dog the strong silent type? Ever wish he or she could tell you when it is time to go do their business? This Reddit r/DIY user found a simple solution — a doggy doorbell!

The dog in question isn’t very vocal, so his owner sought a simple solution, similar to Pavlov’s bells — the only problem? He needed some range on it, as you can’t always hear a few bells throughout the entire house. The solution? A wireless doorbell that he repackaged into a dog friendly button!

Compared to our last post on an automatic pet watering system, this one is a very simple hack that requires absolutely no electrical experience. It could be improved upon quite easily though, by wiring a second switch in parallel so the dog can ring the doorbell from the outside of the house too!

According to the owner, it only took a few treats to get the pooch trained well enough to use it whenever he needs to go out!

[Via Reddit]