I tried this approach.. Two major flaws in it to be aware of. The Multipurpose sensors literally chew through batteries when the accelerometer is active. And the second. probably because our washer is stainless steel, the dan things would fall off every few days.
Wound up using a combination of power monitoring to kick off the start of the automation, and IFTTT & THinQ to trigger the end.
The new SmartThings sensors are really small, you could just use double sided tape to attach them to the side
The back probably isn't stainless and 3M Command strips would stick? Also, hot glue a string to the sensor, and secure the end so when it does fall off, it dangles conveniently, and it isn't an hours log rescue mission. 
I can’t see any vibration attributes to the new SmartThings contact sensors, they just get added as Generic Zigbee contact sensors. Doesn’t seem to be a multipurpose driver?
I'm still using the now deprecated ST Washer Monitor app along with a couple of the prior gen ST multisensors . Along with ActionTiles and the Logitech integration it is the only remaining use for my SmartThings hub. Aside from the 6 month battery life this works well (every time I change the batteries in these things I'm reminded of what pieces of junk they are, with their retention tabs seemingly designed to break off with the next battery change). And they have a convenient low battery alert feature; thoughtfully triggering the "laundry cycle has completed" gong and speech track on my Aeotec Doorbell in the middle of the night when the battery gets low.
Heavy-duty ("Extremely Strong") plastic velcro style 3M strips stick to the sides; that's the only part of my washer/dryer that vibrates enough-- the back is too rigid). The app uses settings for 'fill time' and minimum cycle time; these allow fine tuning so the app won't trigger during a cycle pause or when you slam the door after emptying..
So I was having a problem getting my Xiaomi vibration sensor to pickup on the running dryer. Quick modification with an old spiral notebook and a couple of suction cups and BAZINGA. My rendition of a Xiaomi Vibration Sideways BobbleHead! Works like a CHARM! 
Hmmm ... you would think that the spring would act as a damper, but, as you said, it works.
At first glance at the pic, I thought your dryer was broken, LOL ...
As long as it passes the WAF test... 
I just upped my WAF points and am detecting the dryer being on so that in addition to a washing machine done alert, my wife wants a reminder 20 minutes later if the dryer isn't on. Easy implementation and so far, so good.
That's the name of the game...WAF Test! Keep 'em happy or they'll threaten to rename it to WIFEitat.
You should get the Hubitat Award for Creativity! That is awesome!
I live in California and I think a similar setup would be a great earthquake detector. Of course, the house shaking and rattling is a good indicator too.
awesome
Yeah, I got a good laugh out of that spring mount. It needs some googly-eyes, though.
Ooooh....maybe I'll break into Wifey's craft stuff and decorate the sensor. Haaaa!!
How would you write a rule that would not arm until it has vibrated for a set time. For me, I was thinking that if it vibrates for a minute, that should arm it, then if it doesn't vibrate for 5 minutes, that should trigger the wash complete notification but I have no idea how to write that rule. I'm willing to live with a 6 month battery swap.
"A Rule" <-- that's a bad starting point 
In Hubitat, Rules are free. Start with a rule per state and THEN see if you can reduce.
You'll need a Rule to measure the Arming. That will be tested in the 2nd Rule.
Ok, how would I write a rule to measure the arming? I can see when acceleration is active but I have no idea how to tell when it has been active for 1 minute.
The Vibration sensor hasn't triggered since the last wash, so the False Action has occurred, thus the 'other rule' is disabled by virtue of the Private Boolean.
Once the vibration triggers, it must run for 120 seconds continuous. Any 'false starts' and it gives up, waiting for vibration to start again. When it does run for 120 seconds, the 'other rule' is enabled by virtue of the Private Boolean.
The 'other rule' is dead until the Private Boolean gets True. Once True it waits for vibration to end, continuously for 5 mins, and then sends a message (in this example.)
The "arming" rule waits 5 mins 30 seconds of no vibration to disable the 'other rule.'
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At the bottom of this Rule, inside Restrictions is a switch for the Private Boolean that needs to be on:
Thank you. I haven't gotten the hang of private booleans yet. I thought it through and came up with these two rules. Can you take a look and tell me what the advantages and disadvantages are for each approach... And also is there a way to do push notifications instead of sms?
In this case you are using a Virtual switch device in place of the Private Boolean. Potato / Tomato 
Absolutely. Visit https://pushover.net and create an account for yourself. It's free for a week. $5 for the rest of your life. Completely worth it and you can send 7500 notifications per month, no extra charge.
Next, create a Virtual device and set it to use the built in Pushover driver. You'll need to paste the two 'keys' from the account created to the Device page [Pushover API Key, Pushover User Key] and the name you gave your phone.
Now instead of sending a SMS you just pick that virtual device and Bob's your Uncle.
So there are no advantages or disadvantages to either method... And seeing up pushover now, got a hubitat icon?
Download the Hubitat app
