4 ms·

Again, we've been able to do this with four photodiodes for something like 30 years. Of course it worked the first time they turned it on - they were using 4 p

Again, we've been able to do this with four photodiodes for something like 30 years. Of course it worked the first time they turned it on - they were using 4 photodiodes. The "AI" and "computer vision" is just to get funding and hype. I'm going to start taking solved problems and applying BS "AI" to them to get funding, sheesh.

digitalengineer 7y ago
So (to quote Woz): “a lot of Artificial and not a much Intelligence”?
jws 7y ago
A sun angle sensor is great for pointing at the sun. Heliostats need to bisect a ray to the sun and one to the target. Installation requires somehow setting the angle to the target. Then you immediately become aware of how much the ground heaves throughout the day, so you have to make a foundation that goes well down into the earth. Now you have a $200 heliostat on a $1000 foundation with a $100 calibration operation. Using $50 of computer and camera to steer instead of photodiodes and analog controller (presumably in a splayed viewport configuration) lets you lose the $1000 foundation and simplify the calibration. It’s no longer a precision operation, just a pointing out the target.
- analognoise 7y ago
  No, with the photodiodes you can still steer the mirrors. The mirror part doesn't change. Nothing about the installation changes, except you throw out the "AI" and "computer vision" hype.
  - jws 7y ago
    How do you know where the target is? That's the part where a computer helps. You don't need to see to know where the sun is given a frame of reference, that's just math and a clock. Your frame of reference is initially unknown and varies slightly, but significantly, with time. Training a computer vision system to look for "insanely bright rectangle subtending <1° of space elevated on a stick" is just the thing computer vision is becoming good at. It's even easier than asking my phone to "show me my pictures of goats" (111 hits, zero false positives (assuming sheep are goats)). Of course, a tall skinny field tech should think twice about wearing a short, bulky, white jacket.
anonuser123456 7y ago
I somehow doubt Gates gets fooled by hype. Do you think he just stumbled his way to success? Maybe there is a little more complexity to the problem than you anticipate.
- analognoise 7y ago
  There isn't. "Bill Gates is smart, therefore he can't be fooled or wrong" is not a strong argument.
  - agumonkey 7y ago
    Actually being smart would be leveraging all the hype for maximum coverage, granted the actual product has actual value/benefits.
- deepnotderp 7y ago
  Even Einstein was wrong about some things, that is no argument. But yes, fiducial marks probably don't work well here due to too many variables.
rrss 7y ago
I tried to ask this the last time Heliogen was on HN, but still don't understand the solution, so I'll ask again: You have four photodiodes surrounding the target, and 1000 mirrors aligned to reflect the sun toward that target. One of the 1000 mirrors goes out of alignment, and your photodiodes tell you so. How do you know which mirror needs to be adjusted?

digitalengineer 7y ago

So (to quote Woz): “a lot of Artificial and not a much Intelligence”?

jws 7y ago

A sun angle sensor is great for pointing at the sun. Heliostats need to bisect a ray to the sun and one to the target. Installation requires somehow setting the angle to the target. Then you immediately become aware of how much the ground heaves throughout the day, so you have to make a foundation that goes well down into the earth. Now you have a $200 heliostat on a $1000 foundation with a $100 calibration operation. Using $50 of computer and camera to steer instead of photodiodes and analog controller (presumably in a splayed viewport configuration) lets you lose the $1000 foundation and simplify the calibration. It’s no longer a precision operation, just a pointing out the target.

analognoise 7y ago
No, with the photodiodes you can still steer the mirrors. The mirror part doesn't change. Nothing about the installation changes, except you throw out the "AI" and "computer vision" hype.
- jws 7y ago
  How do you know where the target is? That's the part where a computer helps. You don't need to see to know where the sun is given a frame of reference, that's just math and a clock. Your frame of reference is initially unknown and varies slightly, but significantly, with time. Training a computer vision system to look for "insanely bright rectangle subtending <1° of space elevated on a stick" is just the thing computer vision is becoming good at. It's even easier than asking my phone to "show me my pictures of goats" (111 hits, zero false positives (assuming sheep are goats)). Of course, a tall skinny field tech should think twice about wearing a short, bulky, white jacket.

anonuser123456 7y ago

I somehow doubt Gates gets fooled by hype. Do you think he just stumbled his way to success? Maybe there is a little more complexity to the problem than you anticipate.

analognoise 7y ago
There isn't. "Bill Gates is smart, therefore he can't be fooled or wrong" is not a strong argument.
- agumonkey 7y ago
  Actually being smart would be leveraging all the hype for maximum coverage, granted the actual product has actual value/benefits.
deepnotderp 7y ago
Even Einstein was wrong about some things, that is no argument. But yes, fiducial marks probably don't work well here due to too many variables.

rrss 7y ago

I tried to ask this the last time Heliogen was on HN, but still don't understand the solution, so I'll ask again: You have four photodiodes surrounding the target, and 1000 mirrors aligned to reflect the sun toward that target. One of the 1000 mirrors goes out of alignment, and your photodiodes tell you so. How do you know which mirror needs to be adjusted?