nictinkers

> For any embedded development, or HDL stuff, OS X will not be a nice experience.

My day job is embedded electronics and I prefer to use macOS. I recognise this limits some of my choice of tools but also makes tools available that aren't options for my Windows-using colleagues. Comfortable access to Mac-like tools (OmniGraffle, Acorn, various office suites and code editors) and unix-like tools (gnuplot, LaTeX, simulation and scripting languages) makes up for the fact that I have to run a VM for the accounting software (MYOB) and the occasional Windows-only configuration utility or firmware uploader. Thankfully the business uses the cross-platform Eagle for schematic & PCB work. I've been and Apple guy all the way back to the Apple II so to me, it's nicer to use an OS that I grew up with and suffer the occasional trip to a VM.

That Geckodrive product appears to connect via a standard parallel port. I don't believe Geckodrive has a USB breakout board. You're possibly using the SmoothStepper from Warp9, the KFLOP board from Dynomotion, or one of a couple of Chinese products of widely varying quality.

Once upon a time, the upper end of the market used expensive dedicated hardware for CNC motion control. The low end of the market used commodity PCs ruining the signals out the parallel port.

Nowadays, the high end of the market is using PCs to do complex motion control (with computer vision etc) and the low end is using variants of Arduino boards with firmware like GRBL. With GRBL, the G-code itself is fed out the USB in a serial stream and the hardware does the motion calculations. Having the motion control in dedicated hardware is much nicer than having it on a PC with an operating system that can interrupt the fast timing loops and as hobby electronics gets more capable, you're going to see this set up more and more.

I worry that this circuit has been presented without the relevant warnings. There's no isolation here, so you're exposing people who may go and build this circuit to live mains.

Think about the pot, for example. If somebody built this, and stuck a normal potentiometer on the front of a box to adjust the voltage, they may not think to use a pot that has a high insulation rating between the handle and the wiper. You could get a nasty crack of line voltage DC through the pot handle via your squishy internals and down to ground.

The pictures are also a bit concerning - the big metal heatsinks are almost certainly live as transistor tabs are usually connected to one of the pins and you don't seem to have isolating washers and grommets. I wouldn't want to thread a screwdriver down between live heatsinks to get to the adjustment pot.

This sort of regulator is okay if it and everything it powers is sealed away so nobody can touch it, or if it's powered via an isolating transformer. It's an unusual configuration and it'd be unusual for people to know what must be done to be safe when building this circuit. That unusualness along with the nasty consequences of mistakes means you've got a moral obligation to take care to warn potential builders of some to these issues when presenting this circuit.

> rMBP owners: Please do share your insights into the mean level of abuse your units have handsomely survived.

A week or so ago, I was riding my bicycle on the comute from work and had to avoid a psychopath in a car. I'd forgotten to close the straps over the rMBP and it went flying off the back of the bike, skittered along the bitumen for a couple of metres and smashed into a gutter. It's not quite as handsome as it was, but despite landing on the screen corner everything still lines up perfectly, opens and closes perfectly and works perfectly.