2024 Business Card Challenge: Adding Some Refinement To Breadboard Power Supplies

May 26, 2024 by Bryan Cockfield 6 Comments

For small electronics projects, prototyping a design on a breadboard is a must to iron out kinks in the design and ensure everything works properly before a final version is created. The power supply for the breadboard is often overlooked, with newcomers to electronics sometimes using a 9V battery and regulator or a cheap USB supply to get a quick 5V source. We might eventually move on to hacking together an ATX power supply, or the more affluent among us might spring for a variable, regulated bench supply, but this power supply built specifically for breadboards might thread the needle for this use case much better than other options.

The unique supply is hosted on a small PCB with two breakout rails that connect directly to the positive and negative pins on a standard-sized breadboard. The power supply has two outputs, each of which can output up to 24V DC and both are adjustable by potentiometers. To maintain high efficiency and lower component sizes, a switch-mode design is used to provide variable DC voltage. A three-digit, seven-segment display at the top of the board keeps track of whichever output the user selects, and the supply itself can be powered by a number of inputs, including USB-C or lithium batteries.

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LiPo Replacement Keeps Portable Scanner In The Action

November 21, 2023 by Dan Maloney 8 Comments

If there’s anything people hate more than being locked into a printer manufacturer’s replacement cartridges, it’s proprietary batteries. Cordless power tools are the obvious example in this space, but there are other devices that insist on crappy battery packs that are expensive to replace when they eventually die.

One such device is the Uniden Bearcat BC296D portable scanner that [Robert Guildig] found for a song at a thrift store, which he recently gave a custom LiPo battery upgrade. It came equipped with a nickel-cadmium battery pack, which even under the best of circumstances has a very limited battery life. Using regular AA batteries wasn’t an option, but luckily the space vacated by the OEM battery pack left a lot of room for mods. Those include a small module with BMS functions and a DC-DC converter, a 2,400 mAh 4.2 V LiPo pillow pack, and a new barrel connector for charging. With the BMS set for six volts and connected right to the old battery pack socket, the scanner can now run for seven hours on a one-hour charge. As a bonus, the LiPo pack should last a few times longer than the NiCd packs, and be pretty cheap to replace when it finally goes too. There’s a video after the hop with all the details.

If you’re looking at a similar battery replacement project, you might want to check out [Arya]’s guide to everything you need to know about lithium-ion circuitry.

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Building An Electric Scooter That’s Street Legal, Even In Germany

October 23, 2018 by Dan Maloney 48 Comments

Sometimes a successful project isn’t only about making sure all the electrons are in the right place at the right time, or building something that won’t collapse under its own weight. A lot of projects involve a fair amount of social engineering to be counted as a success, especially those that might result in arrest and incarceration if built as originally planned. Such projects are often referred to as “the fun ones.”

For the past few months, we’ve been following [Bitluni]’s DIY electric scooter build, which had been following the usual trajectory for these things – take a stock unpowered scooter, replace the rear wheel with a 250 W hub motor, add an ESC, battery, and throttle, and away you go. Things took a very interesting turn, however, when his street testing ran afoul of German law, which limits small electric vehicles to a yawn-inducing 6 kph. Unwilling to bore himself to death thus, [Bitluni] found a workaround: vehicles that are only assisted by an electric motor have a much more reasonable speed limit of 25 kph. So he added an Arduino with a gyro and accelerometer module and wrote a program to only power the wheel after the rider has kicked the scooter along a few times – no throttle needed. The motor stops after a bit, needing another push or two to kick it back on. A brake lever kills the motor, as does laying the scooter on its side. It’s quite a clever design, and while it might not keep the Polizei at bay, you can’t say he didn’t try.

[Bitluni] has quite a range of builds, from software-defined television to bad 3D-scanners to precision wine glass whacking. You should check out his stuff. Continue reading “Building An Electric Scooter That’s Street Legal, Even In Germany” →

Hybrid Lab Power Supply From Broken Audio Amp

June 18, 2018 by Ben James 9 Comments

The lab power supply is an essential part of any respectable electronics workbench. However, the cost of buying a unit that has all the features required can be eye-wateringly high for such a seemingly simple device. [The Post Apocalyptic Inventor] has showed us how to build a quality bench power supply from the guts of an old audio amplifier.

We’ve covered our fair share of DIY power supplies here at Hackaday, and despite this one being a year old, it goes the extra mile for a number of reasons. Firstly, many of the expensive and key components are salvaged from a faulty audio amp: the transformer, large heatsink and chassis, as well as miscellaneous capacitors, pots, power resistors and relays. Secondly, this power supply is a hybrid. As well as two outputs from off-the-shelf buck and boost converters, there is also a linear supply. The efficiency of the switching supplies is great for general purpose work, but having a low-ripple linear output on tap for testing RF and audio projects is really handy.