Emerging signs of life

A project log for Heartbeat Logger

A portable device that logs a snippet of your heart at the push of a button.

Ole Andreas UtstumoOle Andreas Utstumo 01/16/2016 at 00:550 Comments


That's what my multimeter read on the analogue front end's output signal after I got the vital parts soldered up. A little touch on the 2.5mm jack socket for the electrode leads and the readings went flying, only to return to 1.63V. Exactly the reference voltage. I got no oscilloscope, but things are looking promising! The micro is up and running, talking to the debugger and Atmel Studio, toggling a LED and powering the front end.

Here's the most recent pic of the circuitboard. Yes, the soldering is terrible, I realised 0603 wasn't as easy without a microscope -- some of the components are completely botched. Since I'm no longer a student, I kinda don't have access to a lot of essential equipment. I guess I need to step up a notch on component size :)

No anti static mat :O

Also, another mistake that became apparent is footprint pad size. Yes, most of the footprints that Altium's CircuitMaker will retrieve for the components aren't suitable for hand soldering at all. The pads should really offer a couple of millimeters extra outside the actual component for the tip of the soldering iron.

The next step is getting those sweet, sweet ADC readings going and throw them onto the memory card.