Altoids Tin Network Analyzer

February 9, 2015 by Brian Benchoff 16 Comments

Network Analyzers are frequently used for measuring filters, making them extremely valuable for building radios and general mucking about with RF. They are, however, extremely expensive. You can, however, build one in an Altoids tin with an Arduino Nano, a small screen, and an AD9850 frequency synthesis module picked up on eBay.

The basic idea behind a network analyzer is to feed a frequency into a device, and measure the amplitude coming out of the device, and plot this relationship over a frequency. [Bill Meara] has been a human network analyzer before, changing frequencies and plotting the output of devices under test by hand. [DuWayne] (KV4QB) build a device to automate the entire process.

The block diagram is easy enough – an AD9850 sends a signal to the device, and this is measured by the Arduino with a small amplifier. The signal is measured again when it comes back from the device under test, and all this is plotted on a small display. Simple, and [DuWayne] is getting some very good readings with a lowpass filter and crystal filter made on a small solderless breadboard.

Watt Meter Build Walks You Through Power Measurement Basics

February 7, 2015 by Anool Mahidharia 27 Comments

You almost never hear of a DC Watt Meter – one just does some mental math with Volts and Amps at the back of one’s head. An AC Watt Meter, on the other hand, can by pretty useful on any workbench. This handy DIY Digital AC Watt Meter not only has an impressive 30A current range, but is designed in a hand-held form factor, making it easy to carry around.

The design from Electro-Labs provides build instructions for the hardware, as well as the software for the PIC micro-controller at its heart. A detailed description walks you through the schematic’s various blocks, and there’s also some basics of AC power measurement thrown in for good measure. The schematic and board layout are done using SolaPCB – a Windows only free EDA tool which we haven’t heard about until now. A full BoM and the PIC code round off the build. On the hardware side, the unit uses MCP3202 12 bit ADC converters with SPI interface, making it easy to hook them up to the micro-controller. A simple resistive divider for voltage and an ACS-712 Hall Effect-Based Linear Current Sensor IC are the main sense elements. Phase calculations are done by the micro-controller. The importance of isolation is not overlooked, using opto-isolators to keep the digital section away from the analog. The board outline looks like it has been designed to fit some off-the-shelf hand-held plastic enclosure (if you can’t find one, whip one up from a 3D printer).

Although the design is for 230V~250V range, it can easily be modified for 110V use by changing a few parts. Swap the transformer, change the Resistive voltage divider values, maybe some DC level shifting, and you’re good to go. The one feature that would be a nice upgrade to this meter would be Energy measurements, besides just Power. For an inside look at how traditional energy meters work, head over to this video where [Ben Krasnow] explains KiloWatt Hour Meters

A DIY Pick And Place You Can Build Right Now

February 6, 2015 by Ethan Zonca 32 Comments

There have been quite a few DIY pick and place projects popping up recently, but most of them are limited to conceptual designs or just partially working prototypes. [Juha] wrote in to let us know about his project, LitePlacer, which is a fully functional DIY pick and place machine with working vision that can actually import BOMs and place parts as small as 0402 with pretty good accuracy.

While some other DIY pick and place setups we’ve featured use fairly exotic setups like delta bots, this machine is built around typical grooved bearings and extruded aluminum. The end effector includes a rotating vacuum tip and a camera mounted alongside the tip. The camera provides feedback for locating fiducials and for finding the position of parts. Instead of using feeders for his machine, [Juha] opted to pick parts directly from pieces of cut tape. While this might be inconvenient if you’re placing large quantities of a single part, it helps keep the design simple.

The software that runs the machine is pretty sophisticated. After a bit of configuration it’s able to import a BOM with X/Y information and start placing within seconds. It also uses the camera to calibrate the needle, measure the PCB using the fiducials, and pinpoint the location of cut tape sections.

If you want to build your own machine, [Juha] published detailed instructions that walk you through the entire assembly process. He’s also selling a kit of parts if you don’t want to source everything yourself. Check out the video after the break to see the machine import a BOM and place some parts (all the way down to 0402).

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DIY SMD Twofer: Manual Pick-and-Place And The Beak

February 5, 2015 by Elliot Williams 23 Comments

Populating a board with tiny SMT parts can be really tricky, and we’ll take all the help we can get. If you’re in the same boat, [vpapanik] has two devices you should check out.

First up is the manual pick-and-place machine. Wait, what? A manual pick-and-place? It’s essentially an un-driven 2-axis machine with a suction tip and USB inspection microscope on the stage. The picker apparatus is the “standard” needle-plus-aquarium-pump design, and the rails are made from angle aluminum and skateboard bearings.

Yeah, yeah, yeah. It’s not a robot. But sometimes the right jig or tool makes all the difference between a manual procedure being fiddly and being graceful. And we couldn’t help but laugh at the part in the video where he demonstrates the “machine” moving in a circular pattern.

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REFLOW CHÂTEAU

February 2, 2015 by Brian Benchoff 29 Comments

[Will] had a few reasons for turning a toaster oven into a reflow oven – he needed a project for an ECE lab, the lab’s current reflow oven was terrible, and the man is trying to keep [Will] down by not allowing toaster ovens in dorm rooms. What was born out of necessity actually turned into a great project – a reflow oven with touchscreen controls.

The toaster oven used for this build is a model [Will] picked up at Sears. It’s actually pretty unique, advertised as a ‘digital toaster’. This isn’t marketing speak – there’s actually a thermistor in there, and the stock toaster is closed loop. After disassembling the toaster and getting rid of the guts, [Will] whipped up a PCB for a Teensy 3.1 and the Adafruit capacative touch shield.

With the Teensy and touch screen, [Will] came up with an interface that looks ten times better than anything you would find on a Chinese auction site. It’s a great build, and since it’s kept in the electronics lab, will certainly see a lot of use.

Give Your Multimeter A Wireless Remote Display

February 1, 2015 by Adam Fabio 27 Comments

Multimeters are one of the key tools in a hardware hacker’s bench. For 90% of us, the meter leads are perfect for making measurements and looking over at the results. Sometimes you need a bit more distance though, and for that, [Ken Kaarvik] has created the Multimeter remote display. Remote displays are pretty handy when you want to measure something several feet away from your bench. They’re also great if you need to check something in an enclosed space, like a server rack or a refrigerator. Fluke actually sells multimeters with wireless displays, such as their model 233.

The key to this project is the FS9721 LP3 chip by Fortune Semiconductor. (PDF link) The FS9721 is essentially a system on chip (SOC) for multimeters. It contains a digital to analog to digital converter, an LCD driver, and a microcontroller. It also can send data out over a 2400 baud serial link. Two of [Ken’s] multimeters, the Digitek DT-4000ZC and a Fluke 17B, both have this chip. The Digitek has a 1/8″ plug for connecting to the outside world, while the Fluke requires some simple hardware mods to enable data output.

Since this was his entry for the Trinket EDC contest, [Ken] connected the serial output of the FS9721 to an Adafruit Pro Trinket. The Trinket formats the data and sends it to an nRF24L01+ 2.4GHz radio module. The receiving end has an identical radio, and another Pro Trinket. [Ken] actually built two wireless displays. One is a dual-boot Game Boy advance which has a really slick background on the color display. The other receiver utilizes a 128×64 OLED. The trinket, nRF24L01+ and display all fit neatly inside an Altoids tin.

Click past the break to see both wireless remote displays in action!

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Emergency Power Based On Cordless Drill Batteries

January 31, 2015 by Mike Szczys 56 Comments

[Don Eduardo] took matters into his own hands after experiencing a days-long power outage at his house. And like most of us have done at least one, he managed to burn his fingers on a regulator in the process. That’s because he prototyped a way to use power tool batteries as an emergency source — basing his circuit on a 7812 linear regulator which got piping hot in no time flat.

His next autodidactic undertaking carried him into the realm of switch-mode buck converters (learn a bit about these if unfamiliar). The device steps down the ~18V output to 12V regulated for devices meant for automotive or marine. We really like see the different solutions he came up with for interfacing with the batteries which have a U-shaped prong with contacts on opposite sides.

The final iteration, which is pictured above, builds a house of cards on top of the buck converter. After regulating down to 12V he feeds the output into a “cigarette-lighter” style inverter to boost back to 110V AC. The hardware is housed inside of a scrapped charger for the batteries, with the appropriate 3-prong socket hanging out the back. We think it’s a nice touch to include LED feedback for the battery level.

We would like to hear your thoughts on this technique. Is there a better way that’s as easy and adaptive (you don’t have to alter the devices you’re powering) as this one?

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