It’s not everyday that we review software around here, but the folks at Adafruit recently put together an iOS app that I figured might be of interest. Their iPad/iPhone compatible application is called “Circuit Playground”, and it includes all sorts of handy electronics reference tools. For the context of this review, it should be noted that I paid for the application myself, and that I have had no communication with the Adafruit team regarding my assessment of the app.

As you can see from the main screen, the app currently features eight different tools, not counting the “Deals @ Adafruit” entry, since I consider that to be more of a marketing strategy than a real tool. The rest of the items are pretty standard reference fare, in an easy to use and understand package.

The Resistor Value tool is pretty straightforward, allowing you to specify resistance in two ways. You can select the color bands of your resistor and view the resulting value, or enter the resistance to see what color resistor you should be looking for. It supports both 4 and 5 band resistors as you would expect, and features a simple “Instruction Page” (as do all the tools), accessible via the small information icon on the bottom left corner of the screen. One thing I would love to see implemented is the ability to photograph components and display their resistance. I think it would be a very helpful addition for makers whose eyesight isn’t what it used to be.

The Multiple Resistor and Multiple Capacitor tools are similar in function, showing you the resultant resistance/capacitance of various series and parallel component setups. They both support up to 9 items apiece, and let you select the capacitance and resistance values for each component one at a time. This is both good and bad, as it gets pretty tedious entering each value manually after a bit. One other item that I thought could use improvement here was the functionality of switching between series and parallel configurations or adding/removing components. Any time a change is made to the configuration, all of the values are reset – this means that if you add another resistor to your 8-resistor diagram, you must re-enter each and every value.

The LED Resistor Calculator does exactly as its name suggests, much like many online calculators that have come before it. This handy feature lets you pick your LED color from a pre-determined list, populating the forward voltage and current fields automatically, based on some common/standard values. Once you specify a supply voltage and quantity of LEDs, the application returns the exact resistance required to meet your specs, along with the value of the nearest standard resistor. While the tool is certainly helpful when calculating resistors for LEDs in series, it lacks any sort of ability to do the same for parallel configurations. If the folks at Adafruit included that functionality along with the ability to customize the default LED list, I would be thrilled. I do have to point out however, that this tool does retain the LED count and supply voltage when changing LED colors, which is something I was glad to see after playing around with the Multiple Resistor tool.

The Ohm’s Law calculator is a simple tool that is great for allowing me to carry out quick sanity checks of the math I have done in my head. Simply enter two values in the triangle, and Circuit Playground spits out the third. The Power Calculator is a similarly straightforward tool, which takes in two of four values (Power, Voltage, Current, Resistance), calculating the rest for you. Neither tool is overly complicated, but then again they don’t need to be.

The final calculator that the app provides makes number conversions dead simple. Given one number, the converter will give you its representation in binary, decimal, hexadecimal, octal, and ASCII notation. While it might not be something that I’ll use every day, it certainly is a very helpful reference tool. I personally think that this tool would benefit from the ability to convert strings of characters/numbers rather than one at a time, but perhaps that is something they are looking to add in a forthcoming release.

One of Circuit Playground’s features that is not as prominent as the others on the main menu is the built-in datasheet viewer. It uses a lightweight interface to help search through and view PDF files located in the iPhone’s document store. I don’t have anything of the sort stored on my phone so I can’t truly test this portion of the app – let us know in the comments how it works for you.

A few data persistence nitpicks aside, I think that Circuit Playground is a solid app with a lot of potential. At $2.99 it sits at the higher end of the App Store pricing structure, so whether or not these tools are worth it is ultimately up to you. Adafruit does say that anyone who purchases the app gets $3 off their next order in their online store, which essentially makes the app free if you are a regular customer.

While it’s not designed for your seasoned Electrical Engineer, it is definitely a great resource for the part-time tinkerers out there. At the moment, it is an iOS-only offering, but Adafruit says that they will be releasing an Android version at some point in the future. In the meantime, they suggest giving ElectroDroid a try, as it is currently the best app on that platform.

What do you do when you’ve got three broken function generators? Build your own, obviously. Since your workshop has already gone through three of these bad boys, you might find yourself repairing your build. Better not use any fancy ICs and go with a transistor only build.

When [Miroslav] sent in his ‘guerilla homebrew’ square wave generator, we were really impressed. With a relatively simple schematic that uses parts that could be salvaged from old radios, this is a real MacGyver build.

The generator is based around a simple astable multivibrator. It doesn’t provide sine waves, but it’s the easiest circuit to get working. The build started off with a quartet of 2N4401 transistors, but according to the datasheet and the venerable Tektronix 502A, these had a very bad rise time compared to 2N3904s.

[Miroslav]‘s project generates square waves up to 2.22 MHz and pulses with a variable duty cycle from 1-49% and 51-99%. Output is either 5 Volt TTL levels or an adjustable 0-3.38 level. The generator is exactly what [Miroslav] needed, so that makes it a great tool in our book.

[msuzuki777] is a self-proclaimed “Lazy Old Geek” with way too much free time on his hands. He recently picked up a laser cross and figured that he would use some of that time to make a laser tripod for various projects around the house.

He pulled out an old camera tripod, and modified an unused CD jewel case so that it could be screwed onto the traditional camera mount. He added three bolts to the platform, on which he mounted another CD case, letting him adjust both the laser platform as well as the tripod.

He put together a simple power supply for the laser, and then mounted it on a pair of CDs sandwiched on top of one another. The CD platform was then popped onto the guts of an old CD player, allowing him to spin his laser pointer in any direction without having to re-level it.

The laser cross tripod certainly looks a bit complicated, but [msuzuki777] says it works a treat, allowing him to easily hang pictures and the like. He also mentions that he wants to throw an Arduino at it to automate the leveling process, which is something we’d love to see.

Students in the BASTLI lab at the Swiss Federal Institute of Technology Zurich had been stuck using underpowered and unreliable saws for quite some time. The saws often got stuck while cutting through PCBs and were generally a drag to use. When group member [Mario Mauerer] came across a big and powerful brushless motor in his basement, he decided it was time to upgrade the lab’s cutting tools.

Along with fellow student [Lukas Schrittwieser] he built a test rig to see how powerful the motor really was, and satisfied with the results, the pair set off to build their own table saw. The enclosure was wrapped up pretty quickly, leaving the pair to source a power supply. Rather than purchase one, they built a 700w monster switching PSU to power their saw.

As you can see in the video below the saw chews through most things with the greatest of ease, but the students added a “boost button” to the saw just in case they need to run it at full tilt.

While we can’t exactly overlook the lack of finger and eye protection in their demonstration, it does look like a great little tool to have around.

When working in hard to reach areas, magnetized tools can mean the difference between wrapping things up quickly and spending way too much time blindly grasping for dropped screws. [Damir] wrote in to share a handy little contraption he built which allows him to magnetize and demagnetize his tools as needed.

While rubbing a magnet against the tip of a screwdriver will impart a weak and temporary magnetic field, he felt that a stronger more permanently magnetized tool was far more useful. It is pretty well known that subjecting metal to a direct current magnetic field will magnetize the item, and an alternating magnetic field will demagnetize the same object. [Damir’s] wand will perform either task with the simple flip of a switch.

He salvaged the motor coil from a broken washing machine and mounted it in a project box, along with a single-pole changeover switch. A small diode is used to perform rectification on the AC input, providing the DC current required for magnetizing his tools.

Every once in awhile we find the need for magnetized tools, so we think this would be great to have around the workshop.

Check out a quick video demo of the magnetizing wand after the jump.

A while back, [Windell] from Evil Mad Scientist Laboratories wrote up an article for Make Magazine detailing how he built a one-ton, servo-controlled scissor jack for under $100. He dropped us a line to let us know that the project details have been released for free at Make Projects, so we stopped by to take a look.

The project starts out by pulling apart an electronic scissor jack to get access to the solder pads for the up and down buttons. Once wires are added there, a servo is the next victim. [Windell] recommends using an old servo with a busted motor, but you can use a good one just the same. The servo’s pots are replaced with 10 turn pots, and then wired up to a controller board, to which the jack is also connected. Then, to provide feedback to the servo, a string is looped around the top of the jack, which is used to turn the pots added in the previous step.

[Windell] says that the setup works quite well, though we imagine the duty cycle might be a bit short before adjustments are required. Regardless, it’s a quick way to get a heavy load lifted with servo precision.

Who needs a Fluke high voltage detector when you’ve got one of these things?

Actually, we still recommend a professional high voltage detector for serious work, but you’ve got to like this electric field detector that [Alessandro] recently put together.

The detector works by using a JFET to detect the high impedance electric fields that are generated by high voltage lines. The JFET amplifies the signal while dropping the impedance in order to drive a pair of NPN transistors which are used as a threshold amplifier. Once the voltage hits 3V, an LED is lit, indicating the presence of high voltage near the detector’s probe. A wire-wrapped resistor does double-duty serving as the probe while providing a high impedance path to ground, ensuring that stray charge does not accumulate on the JFET’s gate, causing false readings.

It’s a neat project, and something that can be constructed in no time, making it perfect for beginner electronics classes.

Keep reading to see a quick video of the HV detector in action.

[Will] had a cheap power supply sitting around, and decided to turn it into a full-featured benchtop PSU. Inspired by some of the other benchtop supplies we have featured in the past, he decided that he wanted his PSU to be more than just a simple-looking box sitting on his work bench. Taking some cues from PC case modding, he put together a unit that is not only very useful, but also quite sharp looking.

The frame of the case was crafted from aluminum angle, while all of the other flat surfaces were made using black polycarbonate. He installed the standard 12v, 3.3v, and 5v terminals you would expect from any benchtop PSU, complete with an LCD display showing the voltages provided by each rail as measured by an Arduino stationed inside the case. Additionally, he installed a variable terminal capable of providing 1.3v-30v, along with its own LCD display. The most unique feature is the multimeter embedded in the front of the case, which makes it virtually impossible to lose.

The case is finished off as you might expect, if you have seen any of his previous work. It features LED lighting on the inside, large fans on either side of the case for optimal air flow, and a pair of machined aluminum handles.

Be sure to check out the quick video below of the PSU being powered on.

[Alex] knows his strippers.

By his estimation, he has stripped millions of wires over the years, and he has seen his fair share of wire strippers come and go. That cheap set of wire strippers you have with the graduated holes, or that adjustable stripper you squeeze as you pull the wire through? They just stress the insulation as well as the wires you are trying to strip – he says you might as well just use them in your tackle box.

His favorite style of wire stripper is the automatic kind that grip the wire, then cut and remove the insulation just by squeezing the handles. His issue with this particular tool is that it’s difficult to get a uniform length of stripped wire when working in volume.

Since [Alex] needs uniformity in his line of work, he modified a set of automatic wire strippers to include an adjustable wire stop. He determines the length of wire he needs, adds or removes some washers from his wire stop, and off he goes. It’s a very simple yet very useful hack, depending on your application. We bet it is probably one of the most accurate ways to get uniform length, this side of a fully automatic wire stripper.

[Erich aka VK5HSE] performs quite a bit of solder reflow work, but has always been concerned about bumping his circuit boards once the solder has liquified and is ready to be removed from the heat source. He says that removing workpieces from toaster ovens often results in the unintentional jarring of a circuit board full of components sitting on molten solder, and he wanted to find a solution.

Using some off-the shelf components from a local hardware store, he built a rig that fits on top of a hot plate, allowing him to move hot circuit boards away from the heat source in a smooth controlled motion. The rig is pretty simple, not only preventing unwanted workpiece movement, but also making it easy to regulate the amount of time a circuit board is allowed to heat.

He suggests that his design is not absolutely ideal, and that it can easily be improved upon in several ways without adding significant cost to the project.

We didn’t believe this hack at all when we saw it, or rather heard it. Surly a guitar made out of a shovel couldn’t sound decent. But the video (after the jump, skip to 2:40 for the jam) to our untrained ears sounded pretty rad. Could be the supremely well done wood work, proper use of tools, high tech pickups, or maybe Russian magic, we don’t know.

In fact, if you continue the video it doesn’t stop there. The creators also made a 2 string bass and a few other instruments from shovels. Do I smell a new shovel hero?

Related: Guitars made out of things that should not be guitars.

[Thanks Paul]

A few weeks ago we held a preorder for the Bus Pirate universal serial interface tool. We split the preorder into two parts due to a shortage of PIC 24FJ64GA002-I/SO chips. The first preorder is arriving worldwide now, the second preorder has a longer lead time. Here’s everything we currently know about preorder 2, it’s subject to change, but we wanted to keep you up to date.

Preorder 2 contains orders for 563 Bus Pirates. Seeed Studio noticed an error in our quality control testing routine that misclassified about 50 preorder 1 Bus Pirates as defective. We updated the test and passing units will ship immediately to preorder 2 participants on a first come, first serve basis. Another 500 PICs are scheduled to arrive after August 1, which should take care of most remaining orders.

A special thanks to the fantastic engineers at Microchip who took the time to peruse the Bus Pirate code, and immediately gave the correct solution to our quality control problem. Great job Microchip, thank you!

We released an updated version of the Bus Pirate firmware package. The firmware is exactly the same, we just changed a speed setting in the P24qp.exe quick programmer utility for MS Windows. During development we increased the baud rate of the quick programmer to make development faster, and we forgot to change it back to a safe speed for normal use.

A decent drill press is a crucial tool for an electronics lab. We use our drill press to make holes in our own circuit boards, and tap or break traces on existing circuit boards. We’ve used a lot of tools to drill circuit boards — power drills, power drills in “drill press stands”, and high-speed rotary tools — but when we started doing projects on a schedule, it was time for something more reliable.

We first spotted the Proxxon TBM115/TBM220 drill press in the window of a local shop.  Its tiny size and adjustable speed seemed ideal for drilling circuit boards. At $200, this is one of the pricier tools in our lab, but quality bearings and smooth drilling action aren’t cheap.  Read about our experience with this tool below the break.

This drill press is tiny, less than a foot tall. It’s easy to tuck away in a closet or under a bed. Despite it’s size, it has all the typical drill press functions like adjustable height and drill depth.

An adjustable drive belt connects the drill head to the motor. The belt moves to different positions on internal pulleys to create three combinations of speed and torque; 1,800, 4,700 and 8,500 rpm. It’s a bit of a pain to adjust the belt, and the instructions for proper tightness are a bit vague.

If the drill is left for long periods, the belt should be loosened so it doesn’t warp. We think our drill press was over-tightened and stood in a hot shop window for more than a year. Now it sometimes suffers excessive vibration and noise after long periods of drilling. This was ameliorated to some extent by the previously mentioned vague adjustment procedure, but we probably need a new belt. While this is a problem specific to our drill, it’s something to consider if you have similar problems, or if you have the opportunity to buy a new belt when you get the drill.

The drill came with 6 collets of various diameters, but no chuck. We bought the collet-compatible drill bit in the photo at the local electronics store for about $10. Reconditioned drill bits are much cheaper on eBay and we’ve also had Drill Bit City recommended to us.

We usually use cheap 0.8mm bits that don’t fit in a collet, so we bought the optional chuck. As you can see in the photo, after a couple years we still haven’t taken it out of the package. The drill is so smooth and straight that the first bit we purchased has lasted through two years of medium-duty use.

Proper safety is imperative when working with high-speed drills and tiny bits. You must wear safety glasses. Every bit will break, it’s just a question of when. A broken bit will usually stick inside the circuit board, but sometimes they shoot out like shrapnel and stick in the woodwork. Not wearing safety glasses while using a high-speed drill almost guarantees you’ll eventually lose an eye. We also wear a dust mask, not just to protect the lungs from fiberglass dust, but to shield the face from broken drill bit debris.

Like our soldering station, this is another tool that we absolutely love. It’s the prefect size for working with circuit boards, and worlds better than any high-speed rotary tool we’ve had the displeasure of using. The drilling action is very smooth, and the motor has tons of speed and torque. The biggest difference to us, migrating from a cordless drill on an old drill press stand, is the steadiness of the drilling head. It drills super sharp holes with no wobble or rough edges. This is one of the most important tools in our lab, and one of our favorites.

The 115volt North American model (TBM 115) is available here for about $200, a search shows several other outlets. The 220volt EU/AUS/world model (TBM 220) is available from here, and a number of online shops. You can also contact Proxxon to find nearby brick and mortar outlets.

We’re big fans of surface mount parts. SMD components are cheaper, take less board space, and don’t require drilling; all the coolest new parts are only available in SMD packages.

Smart Tweezers are an advanced multimeter tool specifically designed to test and troubleshoot SMD circuits. It automatically identifies resistors, capacitors, and inductors, and displays the relevant measurements. Advanced Devices sent us a pair of Smart Tweezers to review. We used them while building our last few SMD projects, read about our experience with this tool after the break.

Tool overview

Smart Tweezers are a multimeter that measures resistance,  capacitance, inductance, and voltage with tweezer-like probes. The probes are shaped to hold loose SMD components, or test components already soldered to a PCB. Measurements are displayed on a small graphic LCD that reverses for left or right hand use. If you’ve ever tried to measure SMD components with a typical multimeter, the value of the tweezer profile is immediately apparent.

Starting at $300, this tool is intended for professionals who regularly debug, test, or repair SMD electronics. It’s a bit out of reach for a hobbyist who just wants to salvage SMD parts.

Using it

We tested the Smart Tweezers while developing three recent SMD projects: the DIY digital picture frame, the Bus Pirate version 1, and an upcoming ethernet device. It’s a real headache to debug an SMD circuit with typical multimeter probes: balance the probes on the correct pins, ensure that the probes don’t create momentary contacts that aren’t due to soldering, and then hold this position long enough to get a good measurement. This only gets worse if you have to repeat several times. The Smart Tweezers test SMD components with a quick single-handed squeeze.

The Smart Tweezers’ graphic menu is navigated with a simple jog wheel. The tool turns on with a press of the jog wheel, and turns off automatically after an adjustable timeout. The default auto-measurement mode attempts to detect the type of component and chooses the best properties to display, but auto-mode is a bit slower than setting a specific measurement mode.

Resistance

Every multimeter measures resistance, a typical multimeter has several test ranges that are toggled manually. The Smart Tweezers measure resistor values between 0.1Ohm and 5MOhms, without manual range adjustments. In the photo we’re measuring a 390ohm, 1% resistor.

Capacitance

Capacitance measurement is a feature that’s found on some high-end multimeters. The Smart Tweezers measure capacitance between 10pF and 499µF. In the photo we’re measuring a 27pF, 5% capacitor commonly used in a crystal oscillator.

A measurement taken from a single capacitor shows its value. A measurement taken from a circuit board shows the total capacitance of all connected components and of the PCB itself.

Inductance

Inductance measurement is rarely found on a multimeter. The Smart Tweezers measure inductance between 1µH and 1H. We didn’t have an SMD inductor to measure, but we tried a through-hole inductor coil from a switch mode power supply.

Voltage

The Smart Tweezers also measure up to 8volts AC or DC. After navigating to the voltage mode, the Smart Tweezers beep until you flip a small, recessed switch in the side of the case. The switch is too recessed to flip with a fingernail, so we used a through-hole resistor lead.

In the photo we’re doing a quick check to make sure that a tiny SOT-23 LTC2631a digital to analog converter is properly soldered to an adapter board and receiving power.

Continuity/Open Test

The Smart Tweezers have a continuity checking mode that beeps to verify connections between parts. This is an easy way to make sure every leg of a large SMD chip is properly soldered, or to hunt for broken/damaged components.

Current

The Smart Tweezers don’t directly measure current consumption, but it’s easy to calculate using voltage and resistance measurements with the equation Ir=Vr/R.

A look inside

As with any tool, we can’t help but take it apart and see what’s inside.

The batteries are replaced by removing three screws and the front cover of the device. This view reveals the batteries, the LCD screen, a small piezoelectric speaker, and the back of the circuit board.

A single screw in the back of the case holds the circuit board in place. We removed the screw to expose the front of the circuit board. The Smart Tweezers are powered by a Texas Instruments MSP430F135 microcontroller and a half-dozen analog chips. The MSP430 line is well-known for low power consumption, and it’s a logical choice for a portable device. Most of the passive support components are size 0402 or smaller.

Conclusion

The Smart Tweezers saved us a lot of time constructing and debugging three surface mount electronic designs. A simple squeeze and test is much faster and easier than awkwardly probing tiny parts with our cheap multimeter. It’s so much easier, in fact, we could hold the Smart Tweezers with one hand and take all the photos in this article with the other; try that with a normal multimeter.

We think two small changes could make the tool even easier to use. First, a larger button would make it easier to switch to voltmeter mode without a wire or screwdriver.  Second, it would be really nice if it could be turned-on by squeezing the tweezers together, rather than pressing the jog wheel.

We really liked the automatic component detection and auto ranging, and the measurement speed is excellent. We appreciate that the tweezer tips are replaceable because we’re really hard on our tools.

If you’re a professional or student who does a lot of work with SMD electronics, a pair of Smart Tweezers can save you time by reducing awkward multimeter measurements to a simple squeeze. This fairly expensive tool is probably overkill for all but the most hard-core hobbyists, but if you derive income from electronics, like we do, Smart Tweezers can be really handy.

Those of you that live in snowier climates will drool over the I-Shovel, a battery powered robot that shovels the snow off your driveway, saving you countless hours of backbreaking labor over the course of a single winter. Its inventors claim that, despite its relatively underpowered motor, it keeps the driveway clear even in heavy snowfall; the trick, apparently, is that the robot constantly monitors the amount of snow on the driveway and springs into action whenever a significant but manageable layer has built up. Unfortunately, the I-Shovel is still a prototype, but with any luck you’ll be able to actually buy one soon. If you’re impatient, of course, you could always try building your own.

[via Toolmonger]