Bench Supply Built In A Power Strip

June 26, 2012 by Mike Szczys 16 Comments

Back in his college days [Print_Screen] grew tired of always building a power supply on his breadboard. To make prototyping quicker he came up with the bench supply that is build into a power strip. This one is using linear regulators for power, and create much less noise on the lines than a supply made from a switch-mode PSU.

First thing’s first, he needed to step down from mains voltage and rectify the AC into DC. He gutted the smallest adapter he could find and managed to fit it into the gutted power strip. It puts out 15V which will work perfectly for the regulators he’s chosen. Each one gets its own slot where an outlet is on the case. The ground hole has been plugged by a toggle switch which routes power to the free-formed regulator/capacitors/heat sink modules. There is a slot for 15V (coming directly off of the converter), 10V, 5V, 3.3V, and two variable regulators which are controlled by the knobs above the outlet. We’ve never seen anything like this and find it most excellent!

[Thanks OverFlow636 via Reddit]

Building A Bench Supply Without Altering The ATX Psu

June 26, 2012 by Mike Szczys 27 Comments

[FozzTexx] has been using a bench supply he made from an AT PSU for years. He put a lot of work into that one, removing unnecessary wires, mounting banana plug jacks on the metal case, and adding an on/off switch and labels. But if it ever dies on him it will be a major pain to do all that work again in order to replace it. When he set out to build another bench supply from an ATX PSU he decided to do so without altering the PSU. This way he can easily swap it out for a different one if he ever needs to.

The hardest part of the hack was sourcing connectors. But with the parts in hand he’s able to just plug the faceplate into the stock connector. This gives him access to all of the voltages, and provides an on/off switch and indicator light. He might also want to add the option of resetting the unit if the over-current protection kicks in.

Toaster Oven Reflow Project Goes Way Overboard

June 18, 2012 by Mike Szczys 29 Comments

This project may take the cake on high-end reflow retrofits. It’s a HUGE project which uses a toaster oven to reflow surface mount circuit boards. And the fact that it bursts with features makes us giddy.

So what parts have we come to expect on these devices? Obviously a heat source which usually comes from a reused toaster oven. Then you need a way to switch the heating elements on and off based on feedback. Since solder profiles have precise timings and temperatures a clock is usually involved. All of this can be done with a temperature probe on a multimeter and a smartphone as the timer. But what we have here is full-automation and then about a thousand more features.

The driver above has a full user interface. It’s got its own PID routines which help to ensure proper holding temperatures and accurate ramping when going from one temperature to the next. The cable exiting the controller below the red buttons is providing feedback via a thermocoupler. So program in your solder profile and let it go. But wait, don’t you want to record and graph what actually happened during this reflow run? Well that’s what the serial connection is for. In fact, you can even load new profiles and control all aspects of the device from a PC interface.

Switching for the toaster oven is done in a different way as well. Instead of just switching mains power, the circulation fan and the heating elements have been electrically separated. This way the fan can run whether the elements are on or not.

Fast And Easy Solder Paste Stencils

June 18, 2012 by Brian Benchoff 12 Comments

If you’re making your own boards with SMD parts, you might want to get a solder paste stencil. Usually made of laser-cut mylar or extremely thin steel, these stencils allow you to squeegee solder paste onto your board’s pads and make assembly a whole lot easier. [Rochey] needed a stencil for a board he was working on, and lacking a laser cutter he turned to what he had available – a few bits of plastic and a CNC machine.

[Rochey] began making his stencils out of laminating pouches and an xacto knife. This worked well, but it was time-consuming, and a bit fiddly when cutting 1 mm square holes. To speed up the process, [Rochey] put one of these laminating pouches on his CNC machine, exported the ‘Top Cream’ layer in Eagle to the CNC software of his choice, and had his machine attack the plastic with a 1 mm drill bit.

To [Rochey]’s surprise, everything went as planned; in five minutes, he had a stencil with perfectly accurate holes that masked off everything but the SMD pads.

Thanks [Fabien] for sending this one in.

BattMan II: The Charger Your Batteries Deserve

June 17, 2012 by Caleb Kraft 13 Comments

When your radio controlled device batteries are drained, you’ve got no better option than to call on BattMan II. This device is packed full of features for cycling and charging various types of batteries. It is computer controlled via your parallel port (yeah, remember those?) and has companion software that allows you all kinds of control and data.

The writeup is rather extensive and includes schematics so you could build your own. There’s also a step by step breakdown of how each section functions as well as an explanation of each different charging method. Great work [Stefan]

if you just want a peak at the lengthy feature list, keep reading.

Continue reading “BattMan II: The Charger Your Batteries Deserve” →

Multimeter Add-on Lets You Measure Tiny Resistance Values

June 15, 2012 by Mike Szczys 15 Comments

This multimeter add-on is called the Half Ohm. It allows you to measure small resistance values, and can be used to track down shorts on a PCB.

The board acts as a pass-through for both probes. When your meter is set to measure voltage and nothing is connected to the probes the display will read out the level of the coin cell that powers the add-on. When you are probing, the value in millivolts is actually showing the resistance in milliohms. This works for any measurement less than one Ohm. Interestingly enough, it will help you zero in on a solder bridge. By probing the two shorted tracks you can find the issue by following the falling resistance values.

[Jaanus] published several posts leading up to the final version of the board. Check out this category link for his blog if you’re interested in reading through them.

Making Giant Wooden Balls

June 13, 2012 by Brian Benchoff 37 Comments

One day, we hope, we’ll be as awesome as [Keith Holaman]. He makes humongous wooden balls with a chainsaw, crane, and a truck-mounted lathe.

[Keith] got his start making wooden balls on a small lathe at home. For some reason he always wanted to make a bigger wooden ball, but his equipment at the time couldn’t handle this size in [Keith]’s imagination.

To make his gigantic wooden balls, [Keith] skulks around his local forest looking for downed trees and stumps. After getting these huge logs home, he roughs out the sphere with a chainsaw, mounts a chuck on the log with huge bolts, and attached it to a diesel motor.

Because the logs are so huge, he can’t turn the log very fast. to remove a whole lot of wood very quickly, [Keith] spins his tool head at a few thousand RPM.

There aren’t many build details or even an indication of how big these wooden balls are. We’d guess they’re easily over a meter in diameter. If anyone knows where we can see these balls in person, drop a note in the comments.