This is a lovely concept, and I’m really glad someone spent the time to commercialize it.
https://en.wikipedia.org/wiki/Knocker-up
Good things:
- It wakes me up. It’s quite difficult to sleep through.
In the very beginning, it makes me feel like I’ve had a heart attack, and jolts me awake with enough gusto and adrenaline that I actually get up.
I am comfortable setting it very early in the morning without being too concerned that I will disrupt the people around me with an alarm going off for 30+ minutes.
- The basic state machine of how an alarm clock works actually needs a bit of care. I don’t like the functionality of some alarm clocks.
This one I do like. The silence button silences it for the day, you don’t need to actively remember.
I have a few gripes.
That said, this is also an assistive device, to be used with people who may have limited sensory function (deafness, deafblindness) - it’s sold on many assitive-dvices stores.
I’m not super chuffed at how barrel plugs were used; I’d prefer something latching for this application, where the wire.
It’s not a super inexpensive unit? The prices seem to have come down very recently, but I spent
I’d like to see some rigidization - the ribbon cables could use some hot-glue to keep them breaking if it falls of your nightstand.
there’s a big weight to stop it falling over.
The bottom has a big scary “electrocution risk!” warning, which is bollocks - I suspect this used to be mains-powered, and they just switched to an external double-insulated wall wart at some point.
The big problem
Because the bedshaker is put on the bed, there is a wire going from the bed sheets to the alarm clock.
They recommend putting the shaker under the mattress, but my bedframe is open, and I don’t see how that could work. I put it under my pillow.
(in fact just putting the shaker on the ground was enough to wake me up).
Something sheets are known for is to cause static sparks. The alarm is not hardened against electrostatic discharge. Just shuffling around in the sheets was enough to cause latch-up the alarm clock in a clearly destructive way; the display would show random values, and various lights would be dimmed indicating weird current paths and mosfets being operated in the linear regime.
Worse still, this fails-silent. I woke up once to find the alarm had latched-up and was having a bad time, presumably after I tossed and turned and built up a nice triboelectric charge - and it wouldn’t have vibrated to wake me.
When this happens, it’s not enough to just unplug the power cord; to clear the latch-up, the 9V backup battery needs to be removed, and then you have to re-program the thing. This makes me grumpy.
This alarm clock occupies a pretty critical part of someone’s life; if it doesn’t work, they could get fired. (there are examples on reddit!). I try to keep redundant and staggered alarm clocks, and have one not be powered by the wall (i.e. battery powered, like a phone), in case of power outage.
It’s kind of interesting to think about how such a little device occupies such an important role in someone’s life.
[!info]
I don’t understand why the bedshaker module is rated for 12V, but the power supply is 9V.
I’m also a little curious about the longevity of this thing - I’m sure it’s just a plain cheapo brushed DC motor, but it’d be nice if it were brushless.
[!success]
The best part of this system is the bedshaker module, and this part can be bought seperately for cheap.Someday, I’d love to build an open-source control module for the bedshaker itself that I’m a little happier with.
Some functions that would be great to have:
Detect if you’ve gotten up, by some means. Could be a weight switch under the bed, or integration with some phone.
More than 2 vibe alarms, with different patterns, “exponential backoff-like” progressively aggressive.
The solution
I installed a TVS diode, a Littelfuse Inc. SNF16A, across the output going to the vibe motor.
I scratched a + where the high-side of the vibe power is. This is a unidirectional TVS; the line on the diode is facing +.
This doesn’t do anything about EMC from sparks nearby, common-mode ESD, or ESD transients coming in through the buttons.
But it seems to have done the trick reasonably enough; I tried make it latch up again, and it hasn’t done so.