A Dim Bulb Tester Is For Testing Other Equipment, Not Bulbs

If you’re testing old stereo equipment, a dim bulb tester can really come in handy. It’s not for testing bulbs, though, it’s a tester that¬†uses a dim bulb to test other things. [Nicholas Morganti] explains it all in his guide to making your own example of such a tool. Just be wary — you need to know what you’re doing with mains voltages to do this safely!

The dim bulb is a deceptively simple tool that nonetheless often proves useful in diagnostics. It normally just consists of a bulb connected in series with the equipment under test. The bulb is intended to be a similar wattage to the power draw of the equipment itself. Take for example, an amplifier. If the bulb glows brightly when the amp is under no load, it suggests there may be a short circuit somewhere. That’s because the glowing bulb indicates that plenty of current is being drawn under a condition when very little should be flowing. The bulb protects the equipment by essentially acting as a bit of a current limiting device. It’s a soft-start tool for a piece of vulnerable equipment.

Building one is usually as simple as gathering an enclosure, a plug receptacle, a bulb socket, and some other ancillary parts to lace everything together. [Nicholas] explains it all with clear diagrams and tells you how to follow along. It’s easy enough, but you really need to know what you’re doing to use one safely, as mains voltages are involved.

It’s a great tool to have if you’re getting into amplifier repair or similar work on old gear. If you’ve been whipping up your own must-have tools, don’t hesitate to let us know!

Modifying Lights For DIY Ambiance

The ESP32 and ESP8266 spread like wildfire a few years ago due to their small form factor, low price, and wireless capability. They didn’t just take over the DIY scene, though. Plenty of mass market products began to incorporate these tiny chips as well, which means that there are some interesting pre-made devices around that are ripe for modification. In this case, using an off-brand smart light bulb as a base for an semi-proprietary lighting setup.

The lighting in this build is a generic RGB light bulb with the ability to control its color over Wi-Fi. Since it has an ESP8266 chip in it, it can be made to work with Philips Hue lights with some minor modifications, allowing a much wider range of control than otherwise available. For this one, [Vadim] needed to pry open the bulb case to access the chip, then solder wires to it for reprogramming. It needed power during this step which meant plugging the resulting mess of wires back into a lamp socket, but after this step the new programming allows the bulb to be reprogrammed remotely.

After that step is complete, though, the generic bulb is ready for its inclusion into a Hue lighting system. In this case, [Vadim] is using diyHue, a Hue emulator that allows control of the bulbs without needing to use any cloud services, running on a BeagleBone. It’s a fairly comprehensive way of adding many different types and brands of bulbs to one system, and avoids any subscription models or the use of a cloud service, which is always something we can get behind.

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Big Clive Hacks LED Bulbs With OpenSCAD

After accidentally crushing the plastic envelope on a cheap LED light bulb, [bigclivedotcom] figured out he could make custom ones using OpenSCAD in any shape he wants. He previously hacked a bunch of these inexpensive LED bulbs last month, discovering they all shared a similar circuit topology. All the ones he experimented with drove the LEDs hard, something that’s bound to reduce bulb lifetime. By reverse engineering the current control regulator, it turns out it is easy to adjust the drive current by changing a resistor or two. Reducing the current should not only increase lifetime, but could allow repurposing the bulb for other uses, such as decorative lighting.

Tweaking the LED Current

Three OpenSCAD scripts are provided which generate what he calls diamond, obelisk, and globe styles. Basic parameters for each style can be tweaked by the user, such as feature sizes and number of facets. He mentions the lack of OpenSCAD customizers in his script — this can easily be added as shown in the following example (this section of the User Manual on customizers explains the syntax). Note that you can’t make the slider generate real numbers, only whole numbers, which is why the scaling factor is multiplied by 10.

Adding Parameter Customization Sliders is Easy

These fancy globes can be used as night lights and possibly outdoor lighting, if you can make a good seal with the base. Custom chandeliers, anyone? Indicator lamps for very large panels? Any other ideas? If you want to explore the LED lifetime issue further, inveterate tinkerer Ted Yapo wrote a deep dive into the mythical 100,000 hour LED bulb. Thanks to [Cliff Claven] for the tip.

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LEDs From Dubai: The Royal Lights You Can’t Buy

[Clive] had an interesting video about LED lights from Philips. You can’t buy them unless you live in Dubai. Apparently inspired by the ruler of Dubai, Sheikh Mohammad Bin Rashid Al Maktoum, who wanted more efficient and longer-lasting bulbs. The secret? A normal LED bulb uses an LED “filament” at 1 watt each. The Dubai bulbs run at about a fourth of that which means they need more LEDs to get the same amount of light, but they should last longer and operate more efficiently.

After exploring the brightness and color of different lamps, [Clive] tears one up and finds some surprises inside. The LEDs get over 200V each and the driver circuit has a lot of pairs of components, possibly to keep the size small for the high voltages involved, although it could be to improve reliability, [Clive] wasn’t sure.

By reducing the power, [Clive] was able to count that each LED strip contains 21 LEDs. He also notes some of the oddities in construction that appear to be for reliability and ease of manufacturing. We aren’t sure how that compares to the construction of conventional bulbs. The circuit includes a bridge rectifier and a linear current regulator using a MOSFET.

The bulbs cost a bit more, but if you factor in the probable long life, their total cost over time should be reasonable. Overall, it is interesting that a nice design came from what amounts to government regulation. Of course, there is a price: in exchange for the development of the bulbs, Philips has the exclusive right to make and sell the bulbs for the next several years. They expect to sell 10 million lamps by the end of 2021, although they are only available, currently, in Dubai.

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Custom Firmware For Cheap Smart Bulbs Is A Cinch To Tinker With

It’s the end of another decade, and while we don’t have real hoverboards, flying cars, or affordable dental care, we do have multicolored lightbulbs you can control over WiFi. [Don Howdeshell] picked up a couple of cheap Merkury branded units in a Black Friday sale, and quickly set about hacking them.

By and large, many of these bulbs are manufactured by various companies and rebranded for whoever happens to place an order. The bulbs tend to use the Tuya IOT ecosystem. Based on the ESP8266, reflashing the bulbs with custom firmware is simple, thanks to the Tuya Convert project. Using a Linux computer with a WiFi card running in Access Point mode, it spoofs a server that tricks the Tuya product into downloading a firmware update. From there, the bulb is an open book, ready to do your bidding.

One of [Don]’s attempts didn’t go so swimmingly, however. Flashing the firmware failed and the bulb was non-functional. [Don] elected to to a teardown, photographing it for our perusal, before hooking up to the ESP8266 directly over its serial interface. From there, it was simple to reprogram the bulb with Tasmota firmware, getting it back up and running.

Security alone is a great reason for running your own firmware on IoT devices. It never hurts to know what you’re connecting to your network!

A Magic Light Bulb For All Your Bright Ideas

[Uri Shaked]’s lamentation over the breaking of his smart bulb was brief as it was inspiring — now he had a perfectly valid excuse to hack it into a magic light bulb.

The first step was disassembling the bulb and converting it to run on a tiny, 130mAh battery. Inside the bulb’s base, the power supply board, Bluetooth and radio circuits, as well as the LED board didn’t leave much room, but he was able to fit in 3.3V and 12V step-up voltage regulators for the LiPo battery.

[Shaked]’s self-imposed bonus round was to also wedge a charging circuit — which he co-opted from a previous project — into the bulb instead of disassembling it every time it needed more juice. Re-soldering the parts together: easy.¬† Fitting everything inside a minuscule puzzle-box: hard. Kapton tape proved eminently helpful in preventing shorts in the confined space.

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Retrotechtacular: The Aerolux Light Corporation

The humble incandescent lightbulb is an invention just about anyone born in the 20th Century is more than familiar with. But it’s not the be all and end all of lighting technology – there are neon lights, compact fluorescent bulbs, and even LEDs are finally being adopted for interior lighting. But with the endless march forward, there are vintage throwbacks to the past – how many hipster cafes have you been to lately with great big industrial-looking filament bulbs hanging from the ceiling?

Even when switched off, they have a striking appearance.

However, that’s not all history has to give us. These gas discharge bulbs from yesteryear are absolute works of art.

The bulbs contain delicate floral sculptures in metal, coated with phosphor, and the bulbs are filled with neon or argon gas. Applying mains voltage to the electrodes inside the bulb causes the phospor to fluoresce, creating a glowing flower that is hauntingly beautiful.

These bulbs were manufactured by the Aerolux Light Company, from the 1930s to the 1970s. Once upon a time, they could be had for as little as 20 cents a bulb – nowadays you’re likely to pay over $50 on eBay or Etsy. The bulbs work by the glow discharge effect, not at all dissimilar to garden variety neon lamps.

While it’s not easy, it is possible to make your own vacuum tubes. Maybe it’s time to order some phospor powder and a tank of neon and get to work? Be sure to document your attempt on Hackaday.io.

Thanks to [Itay Ramot] for the tip!