From Robin Kearey on Hackaday:

The electrical signals emitted by the human body tell us a lot about what’s going on inside. But getting those signals inside your microcontroller is not straightforward: the voltages are too small for most ADCs, and the ever-present 50 or 60 Hz mains frequency makes it hard to discern subtle changes. Over at Upside Down Labs, [Deepak Kathri] developed a universal biosensor interface called the BioAmp EXG Pill to make all this a lot easier.

Its name refers to the fact that it can be used for several different bio-electrical sensing applications: ECG, EMG, EOG and EEG, which deal with signals coming from the heart, muscles, eyes and brain, respectively. To enable such flexibility, the board has connectors for two or three electrodes, as well as solder pads to mount resistors and capacitors to adjust the gain and bandwidth. An instrumentation amplifier increases the strength of the desired signal while rejecting noise and interference.

The form factor allows easy connection to electrodes on one side and a data acquisition system on the other. Measuring just 25.4 mm long and 10 mm wide, it should be easy to integrate into any type of biosensing gizmo you can come up with. [Deepak] has made several demo setups, showing him using the Pill with an Arduino to measure his heart rate, detect eye blinks, and even control a robot arm using his own arm muscles!

The EXG Pill is an evolution of an earlier EMG-only project. We’ve seen several great ECG and EEG projects before, but is the first time we’ve seen one amplifier that can do them all.

Our newest sticker features OreSat,

Our newest sticker 0x1F honors OreSat:

Small educational satellites called CubeSats have been launched by dozens of universities and countries around the world. But so far Oregon has yet to fly our very own artisanally hand-crafted CubeSat. We’re changing that!

We currently have two satellite missions in the works. Both rely on the fully open source “OreSat” bus which we’re offering as an inexpensive (for a satellite!) “DIY” platform for designing and building your own CubeSat.

We’re based out of the Portland State Aerospace Society (PSAS) at Portland State University, but we have collaborators at most other Oregon universities! Here’s a bit more about us.

Here’s how to get involved. You can also follow our development progress on github; OreSat is a completely open source project.

Finally, please also consider donating to support Oregon’s first satellites!

Oskitone has launched the Scout, an Arduino-compatible, monophonic, square wave synth:

• 17 keys
• Custom PCB and 3D-printed hardware
• Satisfying “clicky” tactile switches
• Built-in amplifier, speaker, and output jack
• Powered by 3 AAA batteries
• Open-source and ready to be hacked. Re-programmable with FTDI cable (not included)

Be it the ever shrinking size of components, the miniscule size of the printing on such pieces, or the steady march of time that makes visits to the optometrist an annual ritual, many of us could use some assistance when things start getting fuzzy at the workbench. Arm-mounted LED magnifying lenses can be a handy helper. Zooming in on a macro photo on a smartphone is also a common option that we’ve used many times.

[Timo Birnschein] started down a similar path when he realized that his iPad Pro comes with an app called simply “Magnifier”. A 12” iPad isn’t exactly the most convenient device to hold while trying to solder small parts, so he spent some time designing and 3D printing a specialty iPad stand that he calls a “Quick and Dirty High Performance EE Microscope.” We call it a magnificent tool hack!

Rotating the iPad diagonally so that the camera is closest to the subject leaves plenty of room to work and makes great use of the available screen space. [Timo] reports that at 50% magnification the 12” screen makes even 0603 SMD parts easy to read. Now he rejoices to have more to do with his iPad than watching YouTube and reading Hackaday- although we don’t know why you couldn’t do both.

The STL files have been released on Thingverse for your experimentation. [Timo] notes that he’d like to add an LED ring to brighten things up, and a fume extractor to protect the delicate lens on the iPad. We have to wonder if some plastic wrap over the lens might produce the same effect at almost no cost. Whatever [Timo] decides to do, we’re sure it’ll be brilliant.

Read more on Hackaday…

Saar Drimer writes about an interesting PCB technique:

When I ran the Boldport Club, I arranged a few community pub meets. It was a great way to meet people from the larger community and to see and hear what they’d been working on. In one of those meets, I serendipitously told Mike Harrison about what I’d been designing: an object that required interconnecting pieces of PCBs. Mike, with his extensive electronics installation experience, gave me a wonderfully effective tip: add small ridges along the slots on both pieces that are meant to be put together.

Getting the thicknesses of PCBs right is tricky. Firstly, PCBs normally have a 10% thickness tolerance and another tolerance for the slot/cutout routing. Secondly, the actual thickness depends on the design and on what’s at the surface of where it matters ─ copper, plating, finish, soldermask, silkscreen. So the variation in thickness from ‘nominal’ (0.8 mm, 1.55 mm, etc.) can be significant. We can’t keep experimenting until we get it right either; it’s expensive and somewhat pointless because of the tolerances. Adding ridges allows us to hedge our bets with a single go.

Read more…