No sensor readings from Aeon HEM v1


I received my Aeon HEM v1 from Amazon, paired it with my ST v2 hub, but have not successfully gotten ANY readings out of it consistently.

I plan to use it for washer and dryer notifications, so I have primarily tried “dual clamp” DTHs which support reading current from each sensor individually. I have also tried jscgs350’s DTH, as it seems like the most frequently updated, although I am unsure if supports reading clamps individually.

Here is a Gist link showing the DTHs that I have attempted to use. Not trying to avoid giving credit to those who developed code, but without using GitHub integration, the API makes it difficult to track where the DTH originally came from:

I have tried the troubleshooting techniques that I have read about in existing threads:

  • All DTH generally behave the same – No readings from either clamp sensor
  • I have tried battery and AC and have used with the black button other than for the initial pairing.
  • I have also not connected it to a PC for firmware updates.
  • In the API’s “List Events”, all I have seen are “configure” requests, battery/AC transitions, and the occasional “0 watts” from clamps.
  • On one single occasion, I did get a reading of 3.5W, but I think it was a fluke.

As far as I can tell, the connectors for the clamps are fully seated. I have unplugged and re-plugged the connectors as well. I have not tried using any SmartApps – just DTHs.

Do I have a dud? Should I ask Amazon for an exchange? Or is there some crucial setup piece that I missed?

Thanks for reading,

P.S.: DTHs present two buttons to SmartThings but I only see the one under the battery cover. Anyone know what the other button is?

Where do you have it installed? If it’s on a cable for your washer or dryer then the hot and neutral must be separated in the cord and a clamp goes around one wire only otherwise you get a cancelled-out reading of zero.

And if you have an electric 220V dryer then see here for more help:


The washer and dryer are both 110V. Thanks for the 220 links. I hadn’t considered the point you made about the hot/neutral conductors.

How do folks typically have these sensors configured? Is best practice to buy a short 1-2 foot extension cable to take apart and expose the hot wire?


You don’t expose the wires!!! However the hot and nuetral must be separated.
So yes if you are putting the clamps around both of the wires, you will be getting a 0 reading.

I put mine in the fuse box on the hot black wire as designed

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Best option if you can. In my case there is not enough room in my panel on the individual breaker circuits to get a clamp on the wire. No problem on the main legs in - I just can’t use the HEM on any individual circuit.

I started to go for a HEM on the washer and dryer and ended-up using smart outlets with energy monitoring instead. Looks a bit cleaner too.

For 110 V you can get a small extension cord like this and carefully separate one wire
Cord Extension AC 14/3spt-3x3ft Beige

Thanks for the responses.

I believe the panel option won’t allow for monitoring the washer and dryer individually, as they are on the same circuit.

Call me paranoid, but I try to avoid smart outlets for anything but the occasional floor lamp. Somehow the idea powering large appliances via non-UL devices makes me nervous.

I realize that I already have one of these $3 flat 3-foot “appliance extension” cords:

Similar Walmart option:

I will try to carefully separate (but not expose) the hot or neutral from it. If it works well, I will grab another. I haven’t found one of these higher than 14 AWG but am curious if anyone does.

Thanks again.

Update: Even with a proper wiring setup, I am still having problems.

I carefully separated the neutral wire from the grounding and hot on an extension cord. Then I attached one clamp around neutral, and the other around grounding and hot.

Then I plugged in a lamp via a Kill-A-Watt device to check the current draw. Here is a photo:

I plugged in and re-paired the device, tapped configure a few times, and haven’t seen any readings except for an initial 0 Watts in two hours.

Is there anything else to try?

Should I be concerned that the Device page in the API says “No Data?”

The device page says I have firmware 3.60. Should I update to 3.64? I have not done so already because I read one post criticizing the update and I’m not sure if you can roll back.

Are the two wire bundles too close together?

On a side note, I heard about these today:

More expensive than a $3 extension cable, but it is for the exact functionality we need, and is UL listed.

Can you take a screen shot of the device type you have for your HEM clamps on your graph ide? Trying to see which device handler you are using

Try dth here:

Best laundry alerts for stackable units? see if that works

Thanks for the help smartphi. I saw your post about that dth recently and happen to be using that one at the moment.

Main screen:

Gear/Settings page
(Note: I appear to have lingering variables from other DTHs. Not sure which are needed or if unused ones cause trouble)

And Recent activity. For my recent tests, I labeled Sensor 1 and 2 as “lamp” and “light” – easier than playing with wires behind the washer and dryer.

This is likely your problem. You have both ground and hot in the same clamp so they are cancelling each other out. 1 wire per clamp. 1 clamp on the hot wire and 1 clamp on the neutral.
I only use these on 220 circuits, but that is how I have hooked up every one. The read separately for washer and dryer with the same HEM DTH, you put 1 clamp on the hot for washer and 1 clamp on the hot for dryer.

Thank you for the response. I still have not solved this issue.

I will be happy to be wrong, but neutral/white/groundED and hot/black in the same clamp will “cancel” but green/groundING and either should not, because (unless there is a short) no current flows in it to cancel anything.

In any case, this is a “dual clamp” DTH that reads each clamp independently, and only one clamp has two wires (black/green). The other (white only) should be producing its own reading.

I appreciate the help. Does anyone have any other suggestions?

Have you ever looked inside your electric panel?
The green/bare ground and the white neutral both go to the same lugs. So either with the black or red hot will complete the circuit.
Time to spend some time on YouTube or hire yourself an electrician before you get hurt.

Ok, but shouldn’t the clamp around only neutral be independent with the DTH that Smartphi linked, and provide its own reading?

Have you tried ??

This how i hooked up my fridge and microwave.

After changing to the new Device Type Handler, did you press the CONFIGURE tile? This programs the Aeon HEM v1 to report each clamp’s reading independently. Also, you are using the USB power, correct?

@Smartphi - I have tried that DTH too. Same result with either. Thanks for the pics. Do you use the MikeMaxwell (first one you linked) or the Jmtyra/BarryBurke DTH? Do both work for you?

Could I trouble you for a screenshot of your gear/settings page? I am wondering if one of the values is hosing me.

Last question: Have you updated to firmware 3.64? My device is reporting that it has 3.60.

@ogiewon - Thanks for the help. Indeed I have pressed configure after switching DTH and I am running on USB power. At one point I was also using batteries but I have since removed them, with no change in behavior.

Are you running firmware 3.64 or 3.60? How quickly should I see a sensor reading on the app? Within 1 minute? I see that some DTH have settings to poll every 15 or 30 seconds, but maybe this doesn’t mean what I think it does.