Modular Multicopter Core Flies in Multiple Orientations

[Ioannis Kedros] claims to be rather new to the game of building multi-rotor drones. You’d never know it looking at his latest creation. Yes, we’re talking about the quadcopter seen here, but it’s the core of the machine that’s so interesting. He came up with a PCB hub that allows multiple orientations to be used with the same board. These include tri-copter, and quadcopter with different strut angles for different applications.

multicopter-hub-pcbThe silk screen of the PCB has dotted lines showing the different angles possible for one pair of motor supports. One set makes a perfect “X” for traditional quadcopter flight. Another reduces the angle between front and back struts for higher-performance quad flight, while the last set is intended for a tricopter setup.

We’d recommend taking a look at [Ioannis’] project writeup whether this particular application interests you or not. His design techniques go through all possible manner of checks before placing the PCB order. There is no substitute for this process if you want to avoid getting burnt by silly mistakes.

Continue reading “Modular Multicopter Core Flies in Multiple Orientations”

Upgrading a Laminator for Toner Transfer PCBs

If you need a circuit board now, you’re probably looking at a toner transfer process; all you need to make a PCB is a copper clad board, a laser printer, some special paper, and the usual etching chemicals. The quality of these boards is highly dependant on the quality of transferring toner to the copper, and getting the process right is as much an art as it is a science. A clothes iron is the easy way of transferring the toner to the board, but if you’re looking for repeatability, you’ll probably want a laminator.

Laminators, too, also vary in quality. The king of toner transfer laminators is the Apache AL13P. With four heated rollers and a steel chassis, it’s enough to do some serious heating. [mosaicmerc] came up with an amazing mod for his Apache laminator that takes all the guesswork out of the settings, and does it all in one pass for maximum repeatability and PCB quality.

The Apache laminator in question is a beast of a machine that drives four rollers with a synchronous motor and also has a ‘reverse’ button that sends the laminations out the front end of the printer. Stock, a toner transfer PCB would require dozens of passes through the Apache, but [merc]’s mod takes care of everything for you.

The addition that makes this possible is a small board with a PIC12 microcontroller. This microcontroller connects the motor driver board and the display interface together, triggering the reverse button to move the board 5/8″ forward and 1/2″ back, giving the laminator an effective speed reduction of 12:1. This method also has the bonus of not tampering with the motor or control circuitry, and allows for multiple passes in the same run.

With this modification, the Apache AL13P becomes the perfect solution to transferring toner to a piece of copper, with the ability to transfer 10mil traces on 1oz copper. The board also offers some other features like thermal sensor failure shutdown and a cool-down mode that overrides the heater. If you’re looking for an easy way to step up your toner transfer PCBs, you can’t do much better than this mod.

Make Flexible PCBs with Your 3D Printer

The last few years have seen great strides in budget printed circuit board manufacturing. These days you can have boards made in a week for only a few dollars a square inch. Flexible PCBs still tend to be rather expensive though. [Mikey77] is changing that by making flex circuits at home with his 3D printer. [Mikey77] utilized one of the properties of Ninjaflex Thermoplastic Elastomer (TPE) filament – it sticks to bare copper!

The TPE filament acts as an etch resist, similar to methods using laser printer toner. For a substrate, [Mikey77] lists 3 options:

.004″ thick “Scissor cut” copper clad board from Electronics Goldmine

.002″ thick pure copper polyester taffeta fabric from lessEMF.com

<.001″ Pyralux material from Adafruit, which is one of the materials used to make professional flex PCBs.

A bit of spray adhesive will hold the Flex PCB down on the printer’s bed. The only issue is convincing the printer to print a few thousandths of an inch higher than the actual bed level. Rather than change the home position on his Z axis, [Mikey77] used AutoDesk 123D to create 3D PCB designs. Each of his .stl files has a “spacer bar”, which sits at the bed level. The actual tracks to be printed are in the air a few thousandths of an inch above the bed – exactly the thickness of the substrate material. The printer prints the spacer bar on the bed, then raises its Z height and prints on the flexible PCB material. We’re sure that forcing the printer to print in mid-air like this would cause some printer software to throw errors, but the system worked for [Mikey77] and his Makerbot.

Once the designs have been printed, the boards are etched with standard etching solutions such as ferric chloride. Be careful though – these thin substrates can etch much faster than regular PCB.

Guitar Pedal Hack via Manufacturer’s Shortcut

There seems to be no shortage of manufacturers that cut costs by using similar components across a wide range of products. This isn’t necessarily a bad thing though, since it makes it easier for someone with some know-how to quickly open up the product and figure out how to get more use out of it. [Lewin] noticed some peculiarities on the PCB of his EHX Screaming Bird guitar pedal, and used a manufacturer’s shortcut to turn this treble-boosting pedal into a flat booster.

Once [Lewin] removed the case, he noticed that there were some unpopulated pads on the PCB. Additionally, the potentiometer was labelled as 10k, but a 100k was actually installed. These were indications that something was awry, so after poking around on the internet, [Lewin] now believes that the same PCB was used to make at least three different effects pedals with similar internal structures.

The Screaming Bird pedal was a little harsh for [Lewin]’s taste, so he changed out some capacitors on the board to get it closer to the flat booster. There are some other things that could be changed, but now he has a pedal that suits his needs much more appropriately, thanks to the manufacturer making only minor changes across a range of similar products. Historically, guitar pedals are pretty easy to modify, but it’s nice that the manufacturer of these has made it so much simpler!

The Joys Of Shipping From China

A few months ago, news of a new PCB fab service headed up by [Ian] over at Dangerous Prototypes leaked onto the Internet. It’s extremely cheap – $14 USD for a 5cm square board with free worldwide shipping. [Ian] admits the boards aren’t the greatest quality, that’s not the point; the site’s motto is simply, ‘No bull, just crappy PCBs.’

What began as an internal website to handle all of DP’s PCB orders was now on the Internet, and orders were flying in. At first, shipping a few dozen PCBs around the globe every week was easy, but since Dirty PCBs hit the big time, customers rightfully or not, started freaking out because of the oddities of Chinese shipping and logistics companies.

[Ian] is using Espeed Post for all their shipping, and if you’ve ever ordered anything from China off of Ebay, it’s possible you’ve had something shipped through Espeed before. Because of the oddities of shipping, and the fact that Shenzhen and Hong Kong are right next to each other, even the people at Dangerous Prototypes don’t know which countries your PCBs will go through on the trip from the fab house to your front door. This has caused much consternation with DirtyPCB customers that don’t seem to realize they’re getting custom PCBs for under two dollars a board, shipped to them across the world in a week for free. Some people’s children, huh?

Things get significantly, ahem, dirtier, when Chinese holidays are taken into account. China has a lot of them, and they’re long. They’re just wrapping up the National Day holiday, 10 days in the first week of October. Everyone is backlogged, and the China/Hong Kong border is the mess of trucks seen above.

If a holiday isn’t bad enough, the new President of China is cracking down on corruption. 500 officials were fired at the largest land border with Hong Kong, due in no small part to vans full of meth and tons of counterfeit currency. Every package leaving China is inspected individually, and shipping times have exploded.

To deal with this, Dangerous Prototypes has posted a big red warning on the dirtypcb site, but experience in dealing with people on the Internet tells them this won’t be a viable solution. They’re now dealing directly with DHL, and are apparently getting priority clearance through customs. It’s not fun, as DP will now have to figure out how to work with DHL’s API. It’s a lot of work and a lot of trouble, but DP still has a few tricks up their sleeve – they’re working on an online schematic entry and PCB layout site and the extremely interesting DirtyCables – custom cables shipped to your door.

The Hackaday Prize Semifinalist Update

There are only a few more days until The Hackaday Prize semifinalists need to get everything ready for the great culling of really awesome projects by our fabulous team of judges. Here are a few projects that were updated recently, but for all the updates you can check out all the entries hustling to get everything done in time.


Replacing really, really small parts

accThe NoteOn smartpen is a computer that fits inside a pen. Obviously, there are size limitations [Nick Ames] is dealing with, and when a component goes bad, that means board rework in some very cramped spaces. The latest problem was a defective accelerometer.

In a normal project, a little hot air and a pair of tweezers would be enough to remove the defective part and replace it. This is not the case with this smart pen. It’s a crowded layout, and 0402 resistors can easily disappear in a large solder glob.

[Nick] wrapped the closest parts to the defective accelerometer in Kapton tape. That seemed to be enough to shield it from his Aoyue 850 hot air gun. The new part was pre-tinned and placed back on the board with low air flow.

How to build a spectrometer

spec

The RamanPi Spectrometer is seeing a lot of development. The 3D printed optics mount (think about that for a second) took somewhere between 12 and 18 hours to print. Once that was done and the parts were cleaned up, the mirrors, diffraction grating, and linear CCD were mounted in the enclosure. Judging from the output of the linear CCD, [fl@C@] is getting some good data with just this simple setup.

Curing resin and building PCBs

uv[Mario], the guy behind OpenExposer, the combination SLA printer, PCB exposer, and laser harp is chugging right along. He finished his first test print with a tilted bed and he has a few ideas on how to expose PCBs on his machine.

You don’t need props to test a quadcopter

bladesGoliath, the gas-powered quadcopter, had a few problems earlier this month. During its first hover test a blade caught a belt and bad things happened. [Peter] is testing out a belt guard and tensioner only this time he’s using plywood cutouts instead of custom fiberglass blades. Those blades are a work of art all by themselves and take a long time to make; far too much effort went into them to break in a simple motor test.

SMT and Thru-Hole Desoldering

My introduction to electronic manufacturing was as a production technician at Pennsylvania Scale Company in Leola PA in the early 1980’s. I learned that to work on what I wanted to work on I had to get my assigned duties done by noon or thereabouts. The most important lesson I had learned as a TV repairman, other than not to chew on the high voltage cable, was to use your eyes first. I would take a box of bad PCB’s that were essentially 6502 based computers that could count and weigh, and first go through inspecting them; usually the contents were reduced 50% right off by doing this. Then it was a race to identify and fix the remaining units and to keep my pace up I had to do my own desoldering.

Desoldering with IR System
Desoldering with IR System

It worked like this; you could set units aside with instructions and the production people would at some point go through changing components etc. for you or you could desolder yourself. I was pretty good at hand de-soldering 28 and 40 pin chips using a venerable Soldapulit manual solder sucker (as they were known). But to really cook I would wait for a moment when the production de-soldering machine was available. There was one simple rule for using the desoldering station: clean it when done! Failure to do so would result in your access to the station being suspended and then you might also incur the “wrath of production” which was not limited to your lunch bag being found frozen solid or your chair soaked in defluxing chemicals.

Continue reading “SMT and Thru-Hole Desoldering”