# Key Insights from #hplusroadmap IRC Discussion

• Participants explored DIY flow cytometry and cell counting methods for applications like yeast fermentation, discussing technical approaches including optical methods, impedance spectroscopy, and Coulter counters that can detect cell properties at different frequencies (500 kHz-20 MHz).

• Nick Johnson from Arachnid Labs shared his work on Direct Digital Synthesis (DDS) chips and Arduino libraries for signal generation up to 150MHz, with the group later discussing higher-end options like the AD9958 (500MHz with built-in PLL) and affordable AD9850 modules available on eBay.

• The conversation included detailed technical exchanges about microcontroller options for lab-on-a-chip applications, comparing AVR limitations (80-250 ksps ADC) with faster options like the LPC4370 processor chip with an 80 MSPS ADC.

• Signal processing techniques were extensively discussed, particularly heterodyning and downconversion, explaining how multiplying sine waves of similar frequencies produces sum and difference components that can extract information from high-frequency signals.

• Nick Johnson mentioned his work on an ultra-fast high-speed LED flash capable of 1 million lumens for 500 nanoseconds, which is short enough to stop a bullet without motion blur in photography.

• The group discussed microfluidic chip requirements for cell-flow monitoring experiments, including mixing chambers, backflow prevention valves, and optical clarity for microscope integration, sharing a catalog resource (microfluidic-chipshop.eu).

• Participants shared research on transcranial direct current stimulation (tDCS), discussing how neurons experience "bimodal polarization" with voltage differentials across cells, potentially explaining why pyramidal neurons with soma at the bottom are affected by current flow.

• The conversation touched on neuroscience research showing how dopamine affects time perception, noting that dopamine receptor activation speeds up time perception while antagonists slow it down, with examples from Parkinson's patients experiencing time perception deficits.