# How Does my Blender Detect if lid is on? **URL:** \ **Category:** Factual Questions\ **Created:** [May 8, 2022, 11:00pm UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161 "2022-05-08T23:00:50Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![edwin\_klockars](https://avatars.discourse-cdn.com/v4/letter/e/a9a28c/32.png) [@edwin\_klockars](https://boards.straightdope.com/u/edwin_klockars)\ **Post date:** [May 8, 2022, 11:00pm UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/1 "2022-05-08T23:00:50Z")
I’ve often wondered how the safety feature works on my Blendtec blender which causes the machine not to turn on unless the plastic lid ([Latching Lid – Blendtec](https://www.blendtec.com/products/latching-lid-1) ) is securely on the jar. I am pretty sure there are no sensors in the plastic, so how does it know? In case it matters, here is my blender: [Total Blender Classic | Blendtec](https://www.blendtec.com/products/total-blender-classic) ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [May 9, 2022, 12:16am UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/2 "2022-05-09T00:16:35Z")
I see nothing that would indicate the blender can know that the lid is on. My Cuisinart food processor has a mechanism that prevents the machine from working with no lid on but I do not see anything like that on the Blendtec. ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [May 9, 2022, 12:29am UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/3 "2022-05-09T00:29:32Z")
Probably a photoelectric switch. The lid blocks the light and triggers the switch. It would be in the base of the blender. The lens would be the only thing visible. It might be half the size of a dime. ---
**Author:** ![edwin\_klockars](https://avatars.discourse-cdn.com/v4/letter/e/a9a28c/32.png) [@edwin\_klockars](https://boards.straightdope.com/u/edwin_klockars)\ **Post date:** [May 9, 2022, 12:37am UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/4 "2022-05-09T00:37:00Z")
This is a cool theory! I will try to google and see if there’s any reference to such a thing. Meanwhile, in case it’s helpful, here is a photo of the jar and lid, note that there’s just no where that could conceivably hide a switch, so the photoelectric idea makes sense: [Imgur: The magic of the Internet](https://imgur.com/a/kPUyjvR) ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [May 9, 2022, 12:47am UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/5 "2022-05-09T00:47:40Z")
Hmm. I have what I think is an identical blender and it has no such safety feature. It blends with the lid off or even without the jar. Is yours very new? Mine is less than 4 years old. I’m not sure how a photoelectric system could be reliable. How would it see through the contents of the jar? I suppose it could make use of total internal reflection–using the clear plastic of the jar as some kind of lightpath, and detecting a difference that way–but that doesn’t seem reliable to me. ---
**Author:** ![Kedikat](https://avatars.discourse-cdn.com/v4/letter/k/ed655f/32.png) [@Kedikat](https://boards.straightdope.com/u/Kedikat)\ **Post date:** [May 9, 2022, 12:52am UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/6 "2022-05-09T00:52:03Z")
Does the lid actually have to be in place, or just near. I am thinking maybe some sort of RFID scheme. But that would not be very precise to know the lid was actually in place. ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [May 9, 2022, 12:58am UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/7 "2022-05-09T00:58:54Z")
My last blender would run without the lid. It was my fault if the contents splashed the counter. A mechanical switch would get dirty. That’s why I thought a photoelectric could be used. The lens can be wiped off. Positioning it to work reliably is a concern. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [May 9, 2022, 12:58am UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/8 "2022-05-09T00:58:59Z")
I could not find that feature listed for any Blendtec blender or any mention of this in trouble shooting instructions. The number of ways any such system could fail would prevent it’s implementation. ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [May 9, 2022, 1:13am UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/9 "2022-05-09T01:13:11Z")
The feature is satisfied at 0:34 when the lid is rotated a Tab aligns over the handle. A magnetic switch has to be in it. You’d see the lens of a photoelectric switch. [![](https://img.youtube.com/vi/IMrE1-QoEPs/maxresdefault.jpg "BINATONE Blender - Safety Lid Lock System - How To Guide") ](https://www.youtube.com/watch?v=IMrE1-QoEPs) ---
**Author:** ![edwin\_klockars](https://avatars.discourse-cdn.com/v4/letter/e/a9a28c/32.png) [@edwin\_klockars](https://boards.straightdope.com/u/edwin_klockars)\ **Post date:** [May 9, 2022, 1:15am UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/10 "2022-05-09T01:15:20Z")
It needs to be fully ‘pressed in’ to the top of the jar, if it is just loosely on top it won’t work. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [May 9, 2022, 1:18am UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/11 "2022-05-09T01:18:14Z")
Those have an opaque handle that likely contains a lightpath of some kind, and a lid with a tab that slides up to the top of the handle. So yes, probably a photoelectric system in that case. The Blendtec just has a rubber lid, with no tab, and the jar is all clear plastic with no obvious place for an additional mechanism. And on mine, the base does not have any kind of obvious sensor. It’s all the same black plastic. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [May 9, 2022, 1:18am UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/12 "2022-05-09T01:18:24Z")
Is that the same company? ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [May 9, 2022, 2:22am UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/13 "2022-05-09T02:22:50Z")
> [@aceplace57](#): > > Probably a photoelectric switch. > > The lid blocks the light and triggers the switch. That would be defeated just by the room it’s in being too dark or the operator casting a shadow on it. ---
**Author:** ![Kedikat](https://avatars.discourse-cdn.com/v4/letter/k/ed655f/32.png) [@Kedikat](https://boards.straightdope.com/u/Kedikat)\ **Post date:** [May 9, 2022, 6:42am UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/14 "2022-05-09T06:42:05Z")
Have you tried to detect a magnet embedded in the lid? Can’t see how it would work, but might give a clue. If you have a compass it should detect it. Some stainless steel won’t be attracted. ---
**Author:** ![Kedikat](https://avatars.discourse-cdn.com/v4/letter/k/ed655f/32.png) [@Kedikat](https://boards.straightdope.com/u/Kedikat)\ **Post date:** [May 9, 2022, 6:43am UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/15 "2022-05-09T06:43:32Z")
Near the printing on the jug. Are there extremely small wires running up each side of the printed area? ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [May 9, 2022, 12:00pm UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/16 "2022-05-09T12:00:01Z")
I know where you’re going with that and I don’t think it would work. It would just take a little bit of food or soap scum or oxidation or the lid not being not being 100% fully seated to break the connection. Also, that’s 4 contact points (2 from the base to the container and two from the container to the lid), any one of which could cause a problem. OP, just so we’re all on the same page, have you tried turning the blender on without the lid? Even looking at the directions I didn’t see anything about any such safety feature. Even the troubleshooting section called “My Blender Won’t Turn On” didn’t mention anything about making sure the container and lid were both on and properly seated. Unrelated, but I find it funny that they say it’s “commercial quality” but also “Not for commercial use”. I get it, but at the same time, if it can’t stand up to being used multiple times a day, every day, for years without breaking down, it’s very much not commercial quality. ---
**Author:** ![Kedikat](https://avatars.discourse-cdn.com/v4/letter/k/ed655f/32.png) [@Kedikat](https://boards.straightdope.com/u/Kedikat)\ **Post date:** [May 9, 2022, 2:22pm UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/17 "2022-05-09T14:22:49Z")
Actually I am wondering if there might be a fine wire loop in the jug. And somehow. I do not know how. Inductively coupled, such that some passive in the lid is detected. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [May 9, 2022, 2:28pm UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/18 "2022-05-09T14:28:35Z")
I suppose if there was a wire around the top edge, looped enough times to act as a metal detector, and the lid contained metal, that could do it. I assumed you were thinking the wires would go straight up to the lid, something on the lid would bridge them, creating a circuit and telling the blender that the lid and container are on and properly seated. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [May 9, 2022, 2:47pm UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/19 "2022-05-09T14:47:13Z")
It’s not clear what blender he is talking about. Some other make or model with a locking lid lever makes sense. Something on the blender linked in the OP does not. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [May 9, 2022, 2:50pm UTC](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161/20 "2022-05-09T14:50:30Z")
> [@TriPolar](#): > > It’s not clear what blender he is talking about. > [@edwin\_klockars](#): > > In case it matters, here is my blender: [Total Blender Classic | Blendtec](https://www.blendtec.com/products/total-blender-classic) > [@TriPolar](#): > > Something on the blender linked in the OP does not. I assume that’s why a few people, myself included, have questioned as to whether or not the OP has actually tested out this feature to see if it’s implemented on their specific blender since it doesn’t look like it from the pictures and the directions make no mention of it. [Next page](https://boards.straightdope.com/t/how-does-my-blender-detect-if-lid-is-on/964161.md?page=2)