Afrotechmods

As an EE, trying to understand what this was about fried my brain.

I have a couple of videos that talk about individual components and their critical parameters e.g.

https://www.youtube.com/watch?v=bXEyCf1P0UU

https://www.youtube.com/watch?v=cyhzpFqXwdA

but it sounds like you are looking for content that explains line by line what every parameter means for that component. I definitely understand why you'd be curious about that stuff (I definitely was) but after years of working in the field I came to learn that most of the parameters in a datasheet aren't actually useful or relevant to most designs. For example when picking a MOSFET the datasheet might have 40 lines worth of parameters, but only 5 of them are of actual interest to a designer in 99% of cases. So that's why I chose to produce content that directs the viewer's attention to the most important stuff rather than overwhelming them with edge case scenarios.

Back when this first started Meredith built a "prototype" in a couple of days which, to a layperson, would appear impressive. There was a function generator with an amplifier sending out ultrasound via an array of transmitters and about a meter away there was an array of receiving transducers that picked up the utlrasound. Then the output from those receiving transducers was rectified with a few diodes to get DC. In this demonstration she had a multimeter showing the voltage at the receiving side, and when she tweaked things just right, she received 5 volts on the receiving side. 5 volts is the standard voltage you'd use to charge a phone, or any other USB powered device, so it was reasoned that she had created a viable system that could charge phones wirelessly.

The problem is that any idiot can get 5 volts out of thin air. You can literally hang up a long bare wire and rectify ambient radio waves and get 5 volts. The trick is getting 5 volts and being able to supply significant amounts of current at the same time i.e. receiving useful amounts of _power_. Power = Volts x Amps and Meredith and her investors simply did not understand the importance of this equation that a freshman in engineering would understand. FOMO kicked in and they threw millions of dollars at her thinking it was going to be the next big thing.

1) This is the blog by the former VP of Engineering that the article references: https://liesandstartuppr.blogspot.com/search/label/ubeam

2) Does anyone know if she ever apologized for this awful speech? https://youtu.be/ukgnU2aXM2c?t=240

3) This uBeam shit is literally one of the reasons why I created a beginner's course in wireless power. It drives me nuts that investors have gotten ripped off so many times in this industry and the degree to which the media has been complicit in the hype train. If Mark Cuban or any other VCs happen to be reading this, please watch this course before putting any more money into wireless power. I created a coupon so you can watch it for free.

https://www.udemy.com/wireless-power-to-the-people-wireless-...

I used this phenomenon to build a laser tachometer a while back. https://www.youtube.com/watch?v=RfitqGLPCUY

Thank you. I will surely upload more stuff in future but it won't be on any sort of regular schedule.

Shameless but possibly relevant plug... Here's my introduction to electronics series of tutorial videos: http://afrotechmods.com/tutorials/category/tutorials/beginne...

It's about an hour's worth of material and it is very concise.

Also here in Youtube playlist format: http://www.youtube.com/watch?v=8gvJzrjwjds&list=PLzqS33DOPhJ...

Thank you for sharing your story. If you want to dig deeper into the "why" I would recommend researching spectrum analyzers and how to use them to characterize electromagnetic interference. Example: http://www.youtube.com/watch?v=ctynv2klT6Q You could ask a friend to generate plots for you of the emissions of your laptop, PS2, and the DVD player then figure out if there are specific frequencies that may be causing you problems.

If you are feeling brave you could purchase an RF signal generator and a wideband antenna, and generate pure signals at different frequencies and see which ones cause you problems. A regular function generator may be a cheaper method too as I'm inclined to believe any fields that may be affecting you would be under 1MHz.

It would also be interesting to investigate whether alternating electric fields or magnetic fields affect you more.