Easy To Make Automatic Load Sensing Switch 

Project build article: ibuildit.ca/projects/simple-load-sensing-automatic-switch/ Previous version: ibuildit.ca/projects/automatic-load-sensing-switch/ Please note that this switch will not work for small tools like a sander. It was made specifically for bigger tools that draw more power, like a table saw or miter saw. See the build article for details. Ways you can help support this channel: Patreon: www.patreon.com/user?u=865843&ty=h Project plans for sale: ibuildit.ca/plans/ More videos on my second woodworking channel: ru-vid.com My home reno channel: ru-vid.comHome My "Scrap bin" channel: ru-vid.com Website: ibuildit.ca/ Facebook: facebook.com/I-Build-It-258048014240900/ Instagram: instagram.com/i_build_it.ca/

It’s a FUUULLL BRIGE RECTIFIERRR!!!!

Very nice, John. Viewers: take note of his soldering technique. First he makes a mechanically solid connection. Then he heats up the joint with the soldering iron. Then he feeds in solder and lets it wet the joint. Then he pulls away the solder and the soldering iron and lets the joint cool without touching or moving it. That's how you get a clean, shiny, strong solder joint. This is literally the first time I have seen this done correctly on RU-vid.

Hey John, I advice you to not tin copper strands that go inside a screw terminal (like that mains plug). The tin will compress, making a loose connection that will spark. Especially because here are no springs in this type of connection. Better to crimp wire end bushes over those strands if you're worried of damaging them.

I've always wanted to turn on my drill press with a heatgun!

That's a cool Drill Press remote control :-)

John I only became a sub a short time ago and didn't know you did cool electrical and electronics projects too. This was awesome. Thank you for taking the time to describe what you were doing so clearly!!! I just had a look at the build page and I note you say that the current from the transformer is too low for smaller loads to drive the relay. Could you use a small amp circuit there - perhaps a linear reg + mosfet based between the relay and the rectifier? Could a cap on it's input then also help with the delay on turn the relay off? Anyway I'm not an expert in these things so take what I say as an question rather than a suggestion.

Really cool John! 👍👊

Voy a publicar mi propia versión de esto, mejor? No lo se

Nice job. I do like the electrical box better than the pvc.

Nice work! I've thought about building your previous version for a while, but this one seems like the better option for my needs.

I can use this in the shop and with the RE system. Thanks John, cool video!

Very cool, well done, as always! I'm lucky I was able to buy a Makita shop vac here in Tokyo that has this function built in, and it does work on my sander, tracksaw and hand held router, very nice to have. Cheers from Tokyo!

Find it unreasonably funny that your test is turning on a drill press with a heat gun... since that is a use case that happens all the time.

Pretty neat indeed, John. Great video! Off to read the article.

That's awesome John and I'm not just talking about the Van Halen tshirt 👍🏼👍🏼👍🏼

Pretty spiffy, John!! I use a couple of shop vacs with remotes at each of the main stations I need dust collection. My problem is remembering to turn on the freaking dust collection with the remote. I guess I need a way to ring a bell so this old dog will use that as a tirgger or cue to hit the remote and call it Pavlov's Dust Collection... lol

Next step. "Hey Google, Turn on the dust collection" Nice work!

Very neat :) Used to be able to buy one of these for $20 at Sears but looks like its discontinued and now the options are $40+ so this DIY version does seem worthwhile

Great job. I think a shop with a dedicated vacuum at every large tool would be great.

John, you have some pretty impressive skills their there! Great video and very interesting.

As an electrician. You did a fantastic job.

And to think I was just going to build a toggle switch for my vacuum. This is much more useful.

Thanks. This is a very useful idea, and the explanation/howto is good.

Thanks for sharing. I wish to give it a try but there is no schematic for me to look at in the article. The picture of the circuit diagram has been replaced with a 2500Hz Linkwitz-Riley crossover filter. Not sure if it is a glitch or was intentional. 🙂

So now you can heat your part while drilling it ! =P

You made me google Current Transformers :P very interesting! I wonder if a large value capacitor across the input of the solid state relay would work to hold it on for a little longer, for those people that want that function?

Now you can automate all safety guards! :D Cool video John, as always.

Excellent project! A little heat sink compound on the back of that relay will really help extend it's life. Your use of the box lid as a heat sink was a wise choice. For those thinking about building one, just be aware of the failure modes of an SSR and what that could do to certain types of loads.

That is really nice man. Keep up the good work.

Very pro - great video for your blue channel

i was lucky enough to get a shop vac with this device built in. but if i hadn't i would make one because it helps speed up your work flow and also you never forget to turn the vac on so your lungs will thank you. good work John

Just FYI, the SSR is a knockoff Fotek and probably isn't actually 25A rated, but running on 6-10A may be ok. protosupplies.com/inferior-counterfeit-fotek-ssr-25-solid-state-relays-on-the-market/

I really enjoyed the pov for this video, worked really well

Schematic? John, thank you for sharing. Your ibuildit page for this switch shows the schematic (schematic.png) for your speaker crossover (and the schematic for the crossover is blank Schematic.png). Dave.

Fantastic build. Thanks for sharing.

Nice design and video. I’m having trouble getting the parts list and schematic. I couldn’t find the link on your website… do I have to sign up in I build it? Cheers. Simon

I haven't researched part numbers yet (having just finished watching the video), but Omron makes a number of fixed and/or programmable delay relays. I've had to use several of them at my job, over the years, for a variety of applications. Available, I'm sure, from Digi-Key....or Mouser if D-K doesn't have them. Elegantly simple, efficient design, which I like much better than your original! Great video...Thanks! :-)

I’m excited about this. If this video does well, could you do more electronics videos?

My concern as an electrician is the current draw through that outlet to power both tools - Saws are generally north of 1500W, up to somewhere about 2000W, vacuums anywhere from 800W to 400W so 2300/120 = 19.17Amps best case, worst case 4400/120=36.67 Amps Breakers have a tolerance, they are fired either by a thermal trip - for overload protection or a magnetic strip for short circuit protection, essentially a 20amp breaker won't "trip" immediately on passing its rating, for example a 20amp breaker will run near indefinetely at 22 amps, In the UK / Europe where we use 60898 breakers, that a Type B will within 0.4s trip at 3 to 5 times its rating, a Type C at 5 to 10, and a Type D at 10 - 20. In home / domestic fuse boxes/ panels you generally can only get Types B & C, there is no type A to avoid confused with Amperes. Type C and D are both used to deal with inductive loads to handle their inrush current. For example my dad has a table saw rated at 2000W running on 240V in the UK, the inrush current will trip a 16A Type B breaker, so said breaker has been swapped (after doing all the tests and checks to ensure its safe to do so) with a 20A Type C In your case it may be fine for the short run times of both, won't like lead to any serious cable heating but on a large project with long run times and the saw cutting through hardwoods, the cabling may come close to or exceed its temperature rating due to the current draw.

Just letting you know the schematic for this project on your website is wrong. That schematic is actually of a loudspeaker crossover. BTW I really like the refocus of your channel. Keep up the good work!

Great video. However the schematic on your webpage is not of the auto switch, but of a Linkwitz-Riley filter for a 2-way loudspeaker system. Please check it out.

Great device! Could you list ALL the parts you used? Specifically, the male/female quick-connects are the ones I'm curious about. Also, this can handle a line voltage of 240 V, correct? Thank you!

I've been using this, TrickleStar 7 Outlet Advanced PowerStrip, that I bought on Amazon for 16 bucks. It's a power strip that turns all your components on when it senses your TV turn on. I've been using it for my shop vac for 2 years now without any problems.

Great project! In the build article you have links to Digital-Key for some of the components but not the solid state relay. I’d love to build one of these. Is there a Digi-Key part for the relay that you’d recommend for this project? Thanks!

Wish there was a tutorial like this that would show how to turn on a vent fan automatically whenever my wife turns on the oven or the stove. Since the stove is 240v and the fan is 120v, I'm wondering if there's any solution?

Been watching your channel for a while, been a subscriber for some time, this is fantastic! I’m going to have build a few for my shop, save me a few hundred bucks!

Does this setup work with 230v dust collector? Or better question is how do I get it to work with 110v machines and the odd 230v duster in my shop? I have 230v single outlet for the duster.

Great Project, so useful. I am definitely going to build one based on your design. I have seen ones with arduinos to control the on/off delay, but that would add to many components and increase complexity. I think a hefty capacitor after the rectifier in parallel with the Solid State Relay, would adequately delay the vacuum or auxiliary on/off time. Not necessarily for sucking up any remaining saw dust, but reducing the chance of tripping the breaker, when using a tool like a mitre saw and table saw because of the initial power spikes on start up.

Great project, thanks...... The electronic components for this are dirt cheap! The box, plugs and clamps etc make up most of the cost. Thanks again, one of these is in my future.

Very good! take a doubt; my relay is 220v input so this would work? Of course I eliminating the transformer and point rectifier?

I built this using the exact same parts. It works using my 10Amp heat gun, to turn on my shop vac or drill press (like John's example). However, my miter saw will only turn it on for a few seconds and then the shop vac cuts off. I have learned that it is likely because when cutting something or the fact that when you first turn on a tool it is drawing more current. After a few seconds or when not cutting, the saw draws less amps which makes it no longer turn on this circuit. Since, I didn't realize this until after I spent the money to make 3 of them, I am really hoping that there is something simple I can change to make it work given that my saw is just short of drawing enough amps (even though it is rated at 15 Amps). I was told that it is not uncommon for a 15 Amp saw to draw as little as 8 amps at times. Can I use a different transformer, bridge rectifier or solid state relay to make this work given I'm apparently just a smidgen short of pulling enough amps?

Based on your schematic, you need an electrolytic filter capacitor (about 470uf or better) on the output of the bridge rectifier. This is because the unfiltered DC will have a large noise component that can shorten the life of the SSR.

If you connect it to a vacuum, the vacuum should be turned off after the power tools being turned off. Probably 3 seconds I guess. So you may want to improve it :)

Optionally, if your circuit can't handle both loads (like a table saw and dust collector) you can simply have the relay line voltage plug into a different outlet that is fed by another circuit. The relay doesn't "know" where the line voltage is coming from anyway.

Great video. No need to tin wires for cord cap connections and in crimp terminals. Great build. I am planning on building me some of these. My chop saw is far from my other dust creation tools (L-shaped garage) so I'll be putting a shop vac under the chop saw bench using one of these. I could see combining multiple of these for my jointer, planer, and table saw to trigger my dust collection and even open gates that are normally closed. I'm thinking of using plastic outdoor boxes that will be cleaner for long term dust exposure.

Love your vids but your drillpress is not safe it should not automatic switch on when the power is shut down. With a save drillpress you must after shut down press on ''ON'' again to drill again.

I can definitely see using something like this for some wonderful April Fools' Day pranks.

Hi, does this setup work for 230v dust Collector? I can visualize it... connect the duster into your invention and that connects to the wall?

If your like me and don't have skills to build one. You can just buy one. Then plug anything into it.

nice work...i did something similar for my dust collector but added a off delay timer cube inline with relay to hold open 5 more seconds for that "line clearing" action. Always love to see how other people think along the same lines. Youve got me thinking about switching to solid state relay now LOL.

This seems much more streamlined than Matthias's. Will it work ok in the UK with different voltages?

Very cool! I need an automatic switch that will trigger from a 240 VAC load and operate a 120 VAC device. I need this for a clothes dryer vent booster.

I know it's dangerous but can you show us how it trips and how to reset it? Also I know it's dangerous but if it isn't too dangerous can you show us what it looks like when it shorts out. I watch so many videos about everything going perfect and when one tries to duplicate it there are so many problems it just kills the project and frustration leads to making huge holes in the wall with a hammer or fist.

Nice shirt, project looks useful as well.

And another one bites the dust. After 5 years still wasting our time with a wrong diagram

Thank you for the updated version. I saw your original when you made it too. Good shows.

Now you have a press drill heater ! : )

What would this connection be like for a 110v 220v relay?

If I wanted to make one for lower current devices (sanders), would it just be a matter of a different transformer? Or is it not that simple?

I wish the video showed more... didn't see anything after u explained u was attaching all the to the yellow board and showed us u screw that to the post screws but didnt get to see how any of the wire work is needed to be completed.

Neat and simple. So hard to buy this simple kind of switch in the UK.

Awesome build! Way above my skill level (most things are lol) but awesome!

Great build John, thank you for sharing and for the web article

You dont find that your breaker trips running a 10a vac plus another 12 to 15a tool?

may be the vacuum is connected to ‘normaly closed’ port of ssr and the other tools connected to the relay trigger so when the tools turn on it will cut the current to the vac and as soon as the tools turn off it will turn on the vacuum and suck the dust.., may be :)

We do not solder the soft wires (0:54), but we use tubes. Because of the behavior of a solder, they lose good contact over time.

Hit the thumbs up as soon as I saw the Van Halen shirt \m/ Then, the content was awesome too! Thanks, John!

Nice clean build John. Thanks for sharing.

Great project John! that looks very handy to have in the shop.😎👍JP

Just the best thing ever, superuseful! Thanks so much!

I thought you hooked up a Klondike bar to a cable for a second.

At least you didn't use Axle grease as the heat sink compound as it is better to do without than use that.

“What the hell is going on?!” - Me every time I see someone wiring up something

Could use an off delay relay to keep the vac on a little longer depending on the length of hose attached to it

you are not supposed to tin wires going into screw terminals, it tends to cold flow and get loose over time

John you are on smart cookie I think I'm going to try this. Thank You

660 : Pretty cool, simple design!

Nice shirt mister Heisz, you sent me on a Van Halen binge.

Thought the thumbnail was a klondike bar

Man I miss van halen. Not with Sammy though.

Awesome build John!

Pretty neat. Also, nice shirt.

I'm an electronics person, and I am surprised at how dead simple this is. Great job! If people want to make it run a little longer, they could probably add a small capacitor across the SSR inputs.

I love the MacGyver style music.

The best greentings from Argentina

Nice. Thanks for the video.

This is just plain great. Thanks!

Very cool! I have a 4-outlet box on my work table. Could I somehow chain your device to it so powering on anything plugged into it would triggering the vacuum or would it be simpler to just use it alongside the current box - using one of the 4 plugs to power the relay and plugging the vacuum into the other side?

Nice John BUT I built it and it works just fine if I use a heat gun as the draw but my Dewalt table saw only has enough draw when it initially starts, the vacuum runs, but after 30 seconds or so the vac turns off. I tried other tools such as a miter saw, router all with the same result. But if I use a common hair dryer, not a heat gun, every thing works just fine. My conclusions is that the tools only draw enough current on start up but after stabilizing the current draw is not enough for that transformer to energize the relay. I'm searching for another transformer that will trip at say 7 amps draw. Any thoughts?