[HN Gopher] Hardware Is Hard?
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       Hardware Is Hard?
        
       Author : prdpx7
       Score  : 7 points
       Date   : 2026-04-18 19:34 UTC (3 hours ago)
        
 (HTM) web link (prdpx7.github.io)
 (TXT) w3m dump (prdpx7.github.io)
        
       | cooldk wrote:
       | Hardware is slow
        
       | Neywiny wrote:
       | Thoughts as a computer engineer:
       | 
       | 1. The motor demo didn't work for me (Firefox on Android). Nice
       | to say it was made by Claude.
       | 
       | 2. Voltage isn't like gravity. It's literally called potential.
       | Voltage is the water being high up on the mountain. Gravity is
       | the gravity, which was kinda the point of the analogy, no?
       | 
       | 3. A Tesla has thousands not hundreds of 18650s. But I guess
       | that's a superset.
       | 
       | 4. For motor speed, I would use P = I x V. It shows the way the
       | two work better, and the resulting P = I^2 x R = V^2 / R.
       | Resistance is constant.
       | 
       | 5. PWM wasn't explained right here. You can most certainly vary
       | the voltage without PWM, and it's not just any old modulation you
       | want. You want a binary output so your transistors don't go
       | linear, and you can control the average power. PWM is easy for
       | linear scaling. But you could presumably use other modulations.
       | 
       | 6. It's important to understand what the H bridge is doing, why
       | it matters, and what it offers. Shoot through and dead time are
       | important. Understanding that the microcontroller outputs X
       | current at Y voltage, and the motor needs J current at K voltage.
       | You could drive a small enough motor directly.
       | 
       | 7. Could maybe do a 2-cell charger with balance leads as a
       | usability upgrade.
       | 
       | I think this is a good start and always kudos to those who learn,
       | even more to this trying to teach others. Hopefully there's a
       | part 2 going into more very simple theory. Especially a
       | comparison vs the L298N.
        
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       (page generated 2026-04-18 23:01 UTC)