Home > Electronics, HealthMonitor > 3rd build of pulse oximeter – milled PCB

3rd build of pulse oximeter – milled PCB

November 9th, 2007

img_0001.jpgSo my thought is that we’ll have to try a number of configuration for the pulse oximeter, and it will take too long to iterate through a PCB house, so I decided to make the boards in-house using our Sherline 2000 CNC mill. One comment : IT SUCKS. The damn OS crashes every 5 minutes, it takes 20 minutes to reboot because it wants a network connection, and the application run so slowly that it’s hard to tell if it’s frozen or it’s still drawing the next dialog screen. And when it does work, it throws random errors midway and forces you to start over again. Not to mention the device itself. It’s unstable and the whole platform will rock messing up the z-axis.

Ok, enough of the ranting. After 3 broken end mills, 5 hours over 2 days, and dozens of PC boards, I have successfully milled out a transimpedence amplification circuit based on the OPA380 which is supposed to be the dog’s bollox of tranimpedence amps. The white thing is the backside of the PIN photodiode. I didn’t have a 10MOhm 0805 SMD resistor on hand (I only stock up to 2MOhm, so I went with a through hole resistor).

I might test it out tonight after a few beers, else I’ll test it out in the morning.

Electronics, HealthMonitor

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