3 ms·

Interesting, I’ve always run pis from wall power. Is the pi hardware incapable of similar power optimizations to coral, or is this a problem of a lack of softwa

Interesting, I’ve always run pis from wall power. Is the pi hardware incapable of similar power optimizations to coral, or is this a problem of a lack of software support for power management on pi? (I assume from your mention of external hardware to manage power that it’s not just a software issue.)

dgacmu 2y ago
I'm really mixing two things and wasn't very clear about it. The pico can kinda deep sleep but it requires an external wakeup trigger. It can't deep sleep from its own clock. Even so its deep sleep is pretty high power compared to most embedded chips. The zero (w) and zero 2 w don't have the equivalent of suspend-to-ram with a low sleep current. I'm not sure if that's a limitation of the SOC or the driver or both, but rpi was fairly clear it wasn't in the cards: https://github.com/raspberrypi/linux/issues/1281 https://github.com/raspberrypi/linux/issues/1281
rcxdude 2y ago
I'm pretty sure it's the hardware. The SOCs they use in the mainline pi products are generally targeted at applications which aren't battery powered, so they don't focus on fast sleep support and similar power optimisations (which make the system design much more complex). Unfortunately if you want that you generally need to go with phone SOCs which are generally incredibly NDA-bound, very hard to buy even if you're as big as the rpi company, and have short availability windows which runs counter to requirements of large parts of the SBC market segment.
michaelt 2y ago
A typical battery-powered IoT device like the Ring video doorbell will last ~2 months on a ~6000mAh ~3.3v battery. An average power draw of about 14 milliwatts. This is quite low - a power LED can use more than 14 milliwatts. Of course some products have power consumption even lower than that, right down to the tens-of-microwatts level. Meanwhile a raspberry pi, when idle, consumes ~3 watts [1]. That's 200x more than the video doorbell. Getting the power consumption down requires (a) that your hardware draws very little power when it's in sleep mode, and (b) that it spends as much time as possible in that sleep mode. Hardware and software have to work together to achieve this, and the software changes can be extensive. [1] https://www.jeffgeerling.com/blog/2024/new-2gb-pi-5-has-33-smaller-die-30-idle-power-savings https://www.jeffgeerling.com/blog/2024/new-2gb-pi-5-has-33-s...

dgacmu 2y ago

I'm really mixing two things and wasn't very clear about it. The pico can kinda deep sleep but it requires an external wakeup trigger. It can't deep sleep from its own clock. Even so its deep sleep is pretty high power compared to most embedded chips. The zero (w) and zero 2 w don't have the equivalent of suspend-to-ram with a low sleep current. I'm not sure if that's a limitation of the SOC or the driver or both, but rpi was fairly clear it wasn't in the cards: https://github.com/raspberrypi/linux/issues/1281 https://github.com/raspberrypi/linux/issues/1281

rcxdude 2y ago

I'm pretty sure it's the hardware. The SOCs they use in the mainline pi products are generally targeted at applications which aren't battery powered, so they don't focus on fast sleep support and similar power optimisations (which make the system design much more complex). Unfortunately if you want that you generally need to go with phone SOCs which are generally incredibly NDA-bound, very hard to buy even if you're as big as the rpi company, and have short availability windows which runs counter to requirements of large parts of the SBC market segment.

michaelt 2y ago

A typical battery-powered IoT device like the Ring video doorbell will last ~2 months on a ~6000mAh ~3.3v battery. An average power draw of about 14 milliwatts. This is quite low - a power LED can use more than 14 milliwatts. Of course some products have power consumption even lower than that, right down to the tens-of-microwatts level. Meanwhile a raspberry pi, when idle, consumes ~3 watts [1]. That's 200x more than the video doorbell. Getting the power consumption down requires (a) that your hardware draws very little power when it's in sleep mode, and (b) that it spends as much time as possible in that sleep mode. Hardware and software have to work together to achieve this, and the software changes can be extensive. [1] https://www.jeffgeerling.com/blog/2024/new-2gb-pi-5-has-33-smaller-die-30-idle-power-savings https://www.jeffgeerling.com/blog/2024/new-2gb-pi-5-has-33-s...