Bench Power Supply Constant Current EZ-SET

March 5, 2014 by Todd Harrison 17 Comments

Here is a nice hack you may find very useful if you have a cheaper bench power supply that supports constant current limit protection (CC mode) and the only way to set or check your max current limit is to disconnect your circuit, short the power supply outputs and then check or set your limit. Yes, what a pain! [Ian Johnson] was enduring this pain with a couple of Circuit Specialist bench power supplies and decided to do something about it. After finding a download of the circuit diagram for his CSI3003X-5 supply he was able to reverse engineer a hack that lets you press a new button and dial-in the max current setting. Your first guess is that he simply added a momentary button to short the power supply outputs, but you would be wrong. [Ian’s] solution does not require you to remove the load, plus the load can continue running while you set your current limit. He does this by switching the current display readout from using 0–3 volts off an output shunt resistor to using the 0-3 volts output from a digital potentiometer which is normally used to set the power supplies’ constant current limit anyway. So simple it’s baffling why the designers didn’t include this feature.

Granted this is a simple modification anybody can implement, however [Ian] still wasn’t happy. A comment by [Gerry Sweeney] set him on the path to eliminate the tedious multi-button pressing by implementing a 555 momentary signal to switch the circuit from current load readout to current set readout. This 2nd mod means you just start pressing your up-down CC set buttons and it momentarily switches over the display to read your chosen max current and a few moments later the display switches back to reading actual load current. Brilliant! Just like the expensive big boy toys.

[Ian] doesn’t stop with a simple one-off hack job either. He designed up a proper PCB with cabling and connectors, making an easy to install kit that’s almost a plug-in conversion kit for Circuit Specialist bench power supplies (CSI3003X-5, CSI3005X5, CSI3003X3, CSI3005XIII). It is not a 100% plug-in kit because you do have to solder 3 wires to existing circuit points for signal and ground, but the video covering that task seemed trivial.

This hack could very well work with many other power supplies on the market being Circuit Specialist is just rebadging these units. For now, only the models listed after the break are known to work with this hack. If you find others please list in the comments.

After the break we will link to all three progressive mod videos incase you want to learn how to mod your own power supply or you could just order a prebuilt kit from [Ian].

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Make Your Electronics Lab In A Box

March 5, 2014 by James Hobson 27 Comments

Unless your lucky enough to have a big personal workshop where you can have dedicated stations for all kinds of different tools, you’re probably like most of us here at Hack a Day — lots of projects, but never enough space.

[McLovinGyver] lives in a small flat, and finds setup and cleanup time often take longer than the project itself — so he’s come up with this handy dandy Electronics-Lab-in-a-Box (trademark pending).

The guide is really more of a series of pictures of his process of building the portable lab, but he shows off some great ideas of things you might want to include in your own personal version of it. The first step is deciding what tools you need in the lab. In general, your power supply unit, soldering iron, hot air re-flow and fume exhaustion are going to dictate the general size and shape of your lab — from there, it’s just a matter of filling in the gaps with the rest of your small tools.

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Monster 100W LED Flashlight For Under $10!

March 5, 2014 by James Hobson 63 Comments

What would you do if you came across a 100W, 7500 lumen LED diode for under $10? Probably something like this.

It’s actually quite amazing how cheap LEDs are getting. [Julian Ilett] found this 2″ x 2″ LED on eBay for only £4.79 (<$10 USD). It’s rated for 32-34V with a current draw of 3000mA, which works out to about 100W. Its brightness? 7500 lumens. That’s brighter than most home theater setups.

At that price, [Julian] had to try playing with one. The problem with these higher power LEDs is that they typically need a rather expensive LED driver, due to the less common voltages they operate at — and of course, the concern of over-driving them and burning them out. Not interested in finding a suitable driver, [Julian] decided to try something a bit less conventional — wiring a pair of 18V drill batteries in series.

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Russian Man Builds A Chainsaw Out Of A Grinder

March 4, 2014 by James Hobson 67 Comments

Ready for another ill-advised tool hack we definitely do not recommend you try at home? Why not take a gander at this man’s home-made chainsaw… made out of a grinder! (translated)

What this (Russian?) man has done is modified his large electric grinder — into a chainsaw. He’s added a weld plate, some mounting locations, and now it can accept either grinding wheels, or after a few minutes of assembly, a full length chainsaw blade attachment. He’s probably pretty proud of himself, but we really hope he doesn’t end up losing a finger… or worse.

Anyway, we’re not even going to point out the lack of safety guarding in this video, because it is such an obvious bad idea in general. That being said, it actually works in the demonstration!

Stick around — don’t sweat too much though, no one gets hurt. There is one thing that can be said about this project though… It’s most definitely a hack.

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The Stepper Driver Driver

March 2, 2014 by Brian Benchoff 16 Comments

KONICA MINOLTA DIGITAL CAMERA

The Stepstick and Pololu motor drivers are the heart of just about every Reprap electronics board, but they can go bad. The usual way of testing these things is to rig up a microcontroller on a breadboard, grab some cables, and wire something up. [Ken]’s Easy Stepper Motor Controller is a much simpler solution to the problem of testing these drivers and could, with a bit of practice, be constructed on a single-sided homebrew PCB.

The Easy Stepper Motor Controller is a very simple board with connections to a motor, a power supply, and headers for a single Pololu or Stepstick motor driver. Two buttons and a pot control the rotation of the motor with the help of an ATtiny10, and jumpers for up to 16x microstepping are right there on the board.

There’s a video after the break showing what this stepper motor driver driver can do. It’s not much, but if you’re just testing a driver, it’s all you need.
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BRAIGO – A Lego Braille Printer

February 24, 2014 by Eric Evenchick 11 Comments

Accessibility devices tend to be prohibitively expensive, and it’s always nice to see a hacker apply their skills to making these devices more affordable. BRAIGO is a low cost braille printer by [Shubham Banerjee]. He built the printer using parts from the LEGO Mindstorms EV3 kit, with a few additions. This LEGO kit retails for $349, and a standard braille printer costs over $2000.

The BRAIGO print head uses weights and a pin to punch holes in standard calculator paper rolls. LEGO motors are used to feed the paper and align the head for accurate printing. It takes about 5 to 7 seconds to print each letter, which are entered on the Mindstorms controller.

While this is a great prototype, [Shubham] intends to continue development with the goal of creating an affordable braille printer. He’s a bit swamped with media requests right now, but is working on releasing BRAIGO as an open source project so others can contribute. It’s an impressive project, especially for a 12 year old student. After the break, watch the BRAIGO do some printing.

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An Arduino Programmable Load

February 24, 2014 by Brian Benchoff 31 Comments

Having a big block of hot to dump current into is a very useful thing to have if you’re testing batteries, power supplies, high power LEDs, electroplating, or any thing else that would normally require a huge resistor. [Jakub] found himself in need of an electronic load, and instead of a transistor and a pot, decided to make something more automatic: a programmable load built around an Arduino shield.

The idea behind this load is pretty simple: connect a device to a FET and shunt resistor to measure current. Drive the gate of the FET with an op-amp that maintains either constant current or constant voltage. Control everything with a DAC, and you have a programmable load controlled by an Arduino.

With such a small form factor, getting rid of all that heat was bound to be a problem. For this, [Jakub] is using a 50×50 mm BGA style heat sink with a 5V fan. If it’s good enough for a big CPU, it should be able to handle dumping 70 Watts into a FET. There’s also a conservative application of thermal paste and a very small thermistor underneath the FET that’s able to be read by the Arduino. It might slowly heat up your room, but it’s not going to catch fire.

With the Arduino sketches [Jakub] wrote for his load he was able to characterize a pair of Idea batteries and figure out how much charge a three-year-old recyclable battery had. It’s a great piece of work, and if [Jakub] is willing to go through the hassle of a Kickstarter, it would make a fine crowdfunded product.