@ZeLordz We used a sigma-delta ADC to digitize the signal, and reconstructed it with a 3rd-order CIC (also known as a sinc3) digital filter on the FPGA.
Yes, most of us are engineers at National Instruments by day. Only at night do we make these strangely fun projects. Luckily, National Instruments is quite tolerant of our antics, even if we are ghostriding a Buick around their parking lot, steered with an iPhone.
@WaterlooLabs Yes I knew these guys freshman year! I was an engineering major, but it wasn't my calling. I'm going to be hospital pharmacist however! All the best to you guys.
Hunter, Chris, and Barron have degrees in Electrical and Computer Engineering. Will has a degree in Electrical Engineering. Stephen and Doug have degrees in Mechanical Engineering.
@Izidv That's a great question! I was wondering if anyone would be curious about that. There are three reasons:
1) I originally designed the circuit as an EEG to measure brainwaves, with a gain of 1500. I dialed back the gain a lot to make an EOG, but I didn't know how much it would be until we actually started fiddling with it, so I left all of the amplifiers in and just dropped the gain. We're still playing with the EEG.
2) The amplifier right after the high pass filter needed to have large resistors to cancel the bias current being drawn by the shunt resistor in the high pass filter. If I made the gain too high, the resistors would be too big & add thermal noise.
3) I also designed in an optional potentiometer to null any offset voltage from the amplifiers, so I chose the gain of each one so I could adjust to the full range of our ADC: +- 320mV, but that turned out not to be necessary.
over 3000 volts!!!! no... OVER 9000!
legotransformersonic 9 months ago
@ZeLordz We used a sigma-delta ADC to digitize the signal, and reconstructed it with a 3rd-order CIC (also known as a sinc3) digital filter on the FPGA.
VitalSigns84 1 year ago
What type of converters did you guys use? Sigma-delta, flash, pipelined, SAR, ...???
zeLordz 1 year ago
@zeLordz
If you're interested in the full specs of our isolated sigma-delta ADC, you can find them on analog devices website.
VitalSigns84 1 year ago
you guys work for NI don't you...
legion2 1 year ago
@legion2
Yes, most of us are engineers at National Instruments by day. Only at night do we make these strangely fun projects. Luckily, National Instruments is quite tolerant of our antics, even if we are ghostriding a Buick around their parking lot, steered with an iPhone.
VitalSigns84 1 year ago
hey does anyone know how to add cusom graphics to a PCB in ultiboard?
Spydamonky1 1 year ago
He's wearing a Baylor shirt underneath FTW! Go Baylor Engineering!
SearchForTruth1 1 year ago 3
@SearchForTruth1
Chris and Hunter are Baylor Engineering Alumni. Sic 'em Bears!
VitalSigns84 1 year ago
@SearchForTruth1 Two of the engineers on this project came from Baylor engineering! Sic Em' Bears!
WaterlooLabs 1 year ago
@WaterlooLabs Yes I knew these guys freshman year! I was an engineering major, but it wasn't my calling. I'm going to be hospital pharmacist however! All the best to you guys.
SearchForTruth1 1 year ago
@WaterlooLabs i do notice a GT/ Georgia Tech Banner as well :)
daltonsbadboy 9 months ago
que?
lilfredd1393 1 year ago
\the sweet chica again.... the reason i watched this...
visquex 1 year ago
3:13 that was hilarious! but not 120 v..lol
TechnoFarmboy 1 year ago
Those videos are so freaking awesome but actually you guys are engineer in what?
mathieu1881 1 year ago
@mathieu1881
Hunter, Chris, and Barron have degrees in Electrical and Computer Engineering. Will has a degree in Electrical Engineering. Stephen and Doug have degrees in Mechanical Engineering.
VitalSigns84 1 year ago
Nice explanation! Btw why did you use two amplifiers with a gain of 3, and not one with a gain of 9?
Izidv 1 year ago
@Izidv DID U ACTUALLY UNDERSTAND THIS?!?! ^_^
jtmazing 1 year ago
@Izidv That's a great question! I was wondering if anyone would be curious about that. There are three reasons:
1) I originally designed the circuit as an EEG to measure brainwaves, with a gain of 1500. I dialed back the gain a lot to make an EOG, but I didn't know how much it would be until we actually started fiddling with it, so I left all of the amplifiers in and just dropped the gain. We're still playing with the EEG.
VitalSigns84 1 year ago
@VitalSigns84 Thanks for your clear reply!
Izidv 1 year ago
@Izidv
2) The amplifier right after the high pass filter needed to have large resistors to cancel the bias current being drawn by the shunt resistor in the high pass filter. If I made the gain too high, the resistors would be too big & add thermal noise.
3) I also designed in an optional potentiometer to null any offset voltage from the amplifiers, so I chose the gain of each one so I could adjust to the full range of our ADC: +- 320mV, but that turned out not to be necessary.
VitalSigns84 1 year ago
@Izidv
I guess maybe for noise shaping,, noise decorrelation of the signal? Or something...
zeLordz 1 year ago
this is unintentionally funniest thing ive ever seen
terminatristik 1 year ago 2
Wtf did I just watch?
QuestionMarkPeriod 1 year ago 5