3 ms·

A radio compared to an ARM chip with a display for gaming are not in the same hemisphere of power needs. You simply cannot power a system like that through a cr

A radio compared to an ARM chip with a display for gaming are not in the same hemisphere of power needs. You simply cannot power a system like that through a crank.

twobitshifter 5y ago
It clocks in at 2.74 Wh (740 mAh @ 3.7V). https://www.ifixit.com/Teardown/Playdate+Teardown/143811 https://www.ifixit.com/Teardown/Playdate+Teardown/143811 Assume 75% usable charge that’s about 2Wh. Ads say 8 hour active time so you’d need to make 0.25 W to power it. Say the crank is about 0.1m and you turn it at once per second, 6 radians per second, your force needs to be roughly half a newton when accounting for losses. Half a Newton is about the weight of two AA batteries. So it’s perfectly achievable to keep it running, but we’d have to really think about how much you can output with a hand crank. You wouldn’t want to crank it and try to play at the same time, so you’d be cranking to charge and then play. I found here many crank chargers useful for charging phones and some with as high as 20W output. The ones that are small and cheap can do 1A, 4W, but that would be plenty. 15 minutes of cranking would give 4 hours of play time. https://housegrail.com/best-hand-crank-generators/ https://housegrail.com/best-hand-crank-generators/
- danachow 5y ago
  > 15 minutes of cranking would give 4 hours of play time. Ok that doesn't sound fun at all. But here are the bigger problems: > https://housegrail.com/best-hand-crank-generators/ https://housegrail.com/best-hand-crank-generators/ Those things are fucking huge -- you are comparing some junk ass Ali Express device to proposing actually integrating in the product. Could you find a cheaply and readily available mass produced motor/dynamo that would fit in this 9mm thick form factor and still produce enough power? And at the end of the day the only reason that a device like this is possible for them is they can basically build around easily sourceable, highly integrated parts - The only thing really custom on this is the shell/mechanicals - and that probably blew the majority of their design budget. Spending 10s of thousands for a custom micro dynamo for a dumb feature doesn't seem like well placed priorities. Also, you would have to integrate this without interfering or degrading the primary function of the crank.

A radio compared to an ARM chip with a display for gaming are not in the same hemisphere of power needs. You simply cannot power a system like that through a crank.

twobitshifter 5y ago

It clocks in at 2.74 Wh (740 mAh @ 3.7V). https://www.ifixit.com/Teardown/Playdate+Teardown/143811 https://www.ifixit.com/Teardown/Playdate+Teardown/143811 Assume 75% usable charge that’s about 2Wh. Ads say 8 hour active time so you’d need to make 0.25 W to power it. Say the crank is about 0.1m and you turn it at once per second, 6 radians per second, your force needs to be roughly half a newton when accounting for losses. Half a Newton is about the weight of two AA batteries. So it’s perfectly achievable to keep it running, but we’d have to really think about how much you can output with a hand crank. You wouldn’t want to crank it and try to play at the same time, so you’d be cranking to charge and then play. I found here many crank chargers useful for charging phones and some with as high as 20W output. The ones that are small and cheap can do 1A, 4W, but that would be plenty. 15 minutes of cranking would give 4 hours of play time. https://housegrail.com/best-hand-crank-generators/ https://housegrail.com/best-hand-crank-generators/

danachow 5y ago
> 15 minutes of cranking would give 4 hours of play time. Ok that doesn't sound fun at all. But here are the bigger problems: > https://housegrail.com/best-hand-crank-generators/ https://housegrail.com/best-hand-crank-generators/ Those things are fucking huge -- you are comparing some junk ass Ali Express device to proposing actually integrating in the product. Could you find a cheaply and readily available mass produced motor/dynamo that would fit in this 9mm thick form factor and still produce enough power? And at the end of the day the only reason that a device like this is possible for them is they can basically build around easily sourceable, highly integrated parts - The only thing really custom on this is the shell/mechanicals - and that probably blew the majority of their design budget. Spending 10s of thousands for a custom micro dynamo for a dumb feature doesn't seem like well placed priorities. Also, you would have to integrate this without interfering or degrading the primary function of the crank.