Makita (JDM) Vacuum Remote Start - Page 1
Forum section: electronics / projects

author: Bakafish
author_rank: Contributor
timestamp: September 09, 2020, 09:50:12 am
content: I live in Tokyo and have a Japanese domestic market (JDM) shop vacuum. It has a very useful feature where a corded tool, when plugged into the provided power receptacle on the front, will start the vacuum and then it will shut itself down after a 5 second delay. I use several cordless tools though, and although the newest tools from Makita use a ridiculously overpriced Bluetooth system to emulate this behaviour, this vacuum and the tools I use (primarily a Festool Tracksaw which supports an incompatible Bluetooth system anyway) do not have any support for this.The Goal:Use a cheap Chinese wireless dongle to remotely start and stop the Vacuum.The Challenge:Internally the circuit board that governs the entire operation including the current sensing system is completely potted, so I can't just tap into the existing trigger circuit as I had hoped. All external wiring from the board to the switches and outlet are at line voltage and carry full current. I want to avoid using some kind of switched main outlet as the vacuum can draw as much as 20A when it is supplying power to my bigger saws, and it's just inelegant.The Proposal:The outlet on the front (Tokyo is 100v/50Hz) that does the current sensing is live when in the "automatic" mode. It requires ~10-20 watts of current draw before the vacuum will turn on, it turns off after a 5 second delay when the load is removed (this is intentional as it completes the dust extraction.) My thinking is that if I create a dongle that:1) Plugs into the automatic outlet which provides power2) When triggered by the remote, puts a purely resistive load, just enough to trigger the vacuum3) After creating the load required to start the vacuum, it goes open circuit (no load) for ~4 seconds before again drawing current to keep the vacuum onMy thinking is this switching avoids drawing a continuous load and all the heat and safety issues that would result from that.The Resources:A Chinese wireless key fob and 4-12vdc based board with small relay (7A @ 120v, would prefer it to be running low voltage...)A potted 12vdc 0.45A power supply that is low enough draw to not trigger the vacuum when plugged into the automatic outletMultimeters, Oscilloscope, soldering station and everything required to make a circuit board.Easy access to Akihabara for partsThe Request:I'm a bit of a newb, I understand a lot of the fundamentals but I don't like playing with line voltage without some adult supervision (it really is 100v here, not 110 or 120 here if that matters as far as design.)My expectation is that there would be a straight forward design that uses a transistor capable of handling 100v that gets switched on by the relay from the remote to drive a simple circuit that shorts across a large current limiting resistor, while a timer (maybe a capacitor?) modulates that connection so it is very momentarily engaged every 3 or 4 seconds. The short across the resistor would be fused so if something went wrong it would just blow 'open' rather than create a smoking ball of death...Is there something 'off the shelf' that does this, or is there a better approach given the conditions outlined above? I'm hoping to get some help with the design, and learn some basic solid state switching of 'high voltages' along the way. Any of you able to advise?

author: Bakafish
author_rank: Contributor
timestamp: September 12, 2020, 10:02:05 am
content: I have a circuit designed around a 7555 timer that pulses a half second (10% duty cycle) every 5 seconds. Will wire that to a small 4A solid state relay tied to a 500 Ohm 50W power resistor. Targeting a 20 watt load every 5 seconds. Will update with a schematic and total cost after the parts come and I verify it works.Again, any pitfall avoidance advice would be appreciated.

author: Renate
author_rank: Super Contributor
timestamp: September 12, 2020, 11:32:42 am
content: I would not switch in a fake load to activate the current sensing.I would get a big solid state relay and wire that into the vacuum circuit too.Even with your load idea you still have to switch AC.If the thing with the Bluetooth is the bulk of your problem I would make this work with Bluetooth.A Raspberry Pi Zero W can handle the Bluetooth at the cost of $15 or so.Yes, you will have to figure out the protocol of what's coming out of the Bluetooth tool.If you have other things and you want to use a clicker, you could work with that Bluetooth connection too.Quote from: Bakafish on September 09, 2020, 09:50:12 amI'm jealous.

author: Bakafish
author_rank: Contributor
timestamp: September 12, 2020, 12:27:44 pm
content: I've avoided the whole Bluetooth scam. They use a proprietary protocol, a ridiculously expensive (~$50) dongle, only some tools support it, etc...Festool tools at least trigger off of the batteries themselves, but like cordless batteries, all these manufacturers maintain walled garden profit centers instead of agreeing to a universal standard and interface. I can't blame them, but it is customer hostile.As far as wiring into the vacuum circuit, I can hook up a big relay on the mains, but it actually doesn't help with my current workflow. It would need to be set to the "On" mode and the corded tools wouldn't trigger it (or even work until it was switched on.) Currently, the vacuum stays in "Auto" mode and my corded tools share a Festool cord with a "Plug It" bayonet connector. It makes it really easy to grab a tool, plug in the AC quick connect and the hose, then just get work done. Putting an additional switch in front of that is ugly and is just trading off one inconvenience for the other. As of now when I switch to a cordless, I need to go switch the vacuum to manual (which sucks), but if my device works as I proposed I can in-line it with the Festool quick change electrical cord and the vacuum will trigger off of a corded tool, or the remote, all without any direct intervention.Obviously this is a small nuisance, but reducing friction in workflows really makes the job more pleasant. A new Festool vacuum that does both current sensing and a remote fob start is about $2000 here in Japan, so a few hours and $100 to mod my little Makita to do the same job is a win in my book. (To be complete, Makita sells a $200 Bluetooth based retrofit device in the US that is similar to what I'm trying to build, but they do not make a pure Remote Trigger fob, you need to buy the $50 modules for your tools, againifthey support the feature. I assume they know people would just buy one fob and not spend hundreds of dollars on their stupid transmitters.)

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 12, 2020, 12:53:19 pm
content: Most likely it's sensing current rather than power, so a motor run capacitor (10uF gives about 30VA) will make a nondissipative "load" to trigger it. Add a 100k or so resistor across it to avoid surprises and use a zero cross SSR to switch it in.

author: Renate
author_rank: Super Contributor
timestamp: September 12, 2020, 12:58:00 pm
content: No, I'm suggesting wiring in the new SSR in parallel with the potted blob switch for automatic.You can reverse engineer the Bluetooth protocol.It can't be rocket science, probably just GATT.I've done that with the iRig BlueBoard foot switch which only has user software for Apple so I can do Android.

author: Bakafish
author_rank: Contributor
timestamp: September 12, 2020, 01:19:13 pm
content: Quote from: NiHaoMike on September 12, 2020, 12:53:19 pmIf I understand you correctly, the main advantage to this would be a smaller resistor as it would just be draining the cap between pulses. My concern is that in my testing, it takes a sustained (~20W) load for at least a half second (it may be a full second, I will know when I actually build the circuit and start testing it.) A single 10w bulb isn't enough, but 2 of them will trigger it. If I blip the load too fast it will not trigger, so I think a cap charging will not give a long enough draw to work.The resistor and SSR can both handle a continuous 20 watt load, assuming I manage the heat (based on the photos I've seen of the Makita version I mentioned above, I think they are just switching in a constant load and dissipating the heat), but if I can pulse it with the timer circuit I can reduce the continuous load on the SSR/resistor, limit the heat generation and hopefully improve reliability.

author: Bakafish
author_rank: Contributor
timestamp: September 12, 2020, 01:23:29 pm
content: Quote from: Renate on September 12, 2020, 12:58:00 pmThe CN remote relay unit was $9... I do not want the complexity of Bluetooth at all, none of my units have the transmitters, I do not want to buy them. I want a button on the hose that I can push to make it suck, this achieves that goal.

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 12, 2020, 03:34:12 pm
content: Quote from: Bakafish on September 12, 2020, 01:19:13 pmA capacitor connected to AC will draw current like a resistor does, but at 90 degrees out of phase so it doesn't dissipate power.

author: Bakafish
author_rank: Contributor
timestamp: September 13, 2020, 02:21:20 am
content: Quote from: NiHaoMike on September 12, 2020, 03:34:12 pmUnderstood. But you need to drain that charge with a resistor to 'reset' it for the next cycle, right? And unless I'm using some seriously massive (and expensive) cap, I can't imagine it will draw current for the ~500ms required to trigger the sensor. So the only advantage I see is that I can spec a smaller resistor to dissipate the energy stored in the capacitor over the 90% downtime of the duty cycle, but you add an expensive capacitor. As the power resistor I'm using was about $4, and I will be able to adjust the duty cycle using the 555 to ensure it triggers, I still think my design may be preferable. I'm new to this stuff though, so if I'm missing something obvious let me know.

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 13, 2020, 03:11:30 am
content: Quote from: Bakafish on September 13, 2020, 02:21:20 amThe capacitor is constantly charging and discharging when connected to AC. The only purpose of the high value resistor across it is to discharge it when disconnected so it doesn't unexpectedly hold a charge to to zap you when you work on it. Also, motor run capacitors are cheap.

author: kripton2035
author_rank: Super Contributor
timestamp: September 13, 2020, 06:22:06 am
content: some ideas here :http://kripton2035.free.fr/master-slaverepo.htmlit's for european 220v system but should be easily transposed.

author: Bakafish
author_rank: Contributor
timestamp: September 13, 2020, 09:00:45 am
content: Quote from: NiHaoMike on September 13, 2020, 03:11:30 amOh! I didn't realize that a cap discharges when left in (an AC) circuit, makes sense I guess. I think you are saying that I can just switch a motor capacitor 'in circuit' using the SSR and it will present a load that triggers the sensor. No need for a timer circuit as it will happily stay under load without excessive heat as long as I'm likely to need. Can you give me a suggested Farad rating? I have some big caps I pirated from an old AC I just replaced, I believe they were there for the compressor and cooling fan motors.

author: Bakafish
author_rank: Contributor
timestamp: September 13, 2020, 09:17:56 am
content: Quote from: kripton2035 on September 13, 2020, 06:22:06 amThe current sensing circuit is already built into the vacuum, unfortunately it was totally potted so I can't fiddle with it. I'm trying to create a safe way to remotely trigger it without having to replicate all that functionality. That linked circuit is a really handy design though!

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 13, 2020, 12:48:11 pm
content: Quote from: Bakafish on September 13, 2020, 09:00:45 amWhich values do you have? 7.5uF would be close to the minimum needed for it to work (so I would say you want at least 10uF) and the maximum would be limited by the maximum current of the circuit, far larger than common motor run capacitors. Do make sure it's a motor run capacitor, since motor start capacitors are not rated to withstand voltage for an extended time. (Post a picture if you're not sure.)

author: Renate
author_rank: Super Contributor
timestamp: September 13, 2020, 01:13:29 pm
content: The capacitor idea is really clever, but I hate it.I don't want to put big capacitors across a power line.We used to do that with electrolytics for fun.Heck, I don't even want to put resistors across a power line.

author: Monkeh
author_rank: Super Contributor
timestamp: September 13, 2020, 01:49:44 pm
content: Quote from: Renate on September 13, 2020, 01:13:29 pmPutting big capacitors, resistors, and inductors across a power line is what you do every time you use any appliance. Get used to it.

author: Bakafish
author_rank: Contributor
timestamp: September 14, 2020, 02:58:13 am
content: Quote from: NiHaoMike on September 13, 2020, 12:48:11 pmI have 2Nichicon360μF (350μF tested) 85° 250 working voltage units and a singleMarconCE62W 1000μF (950μF tested) 85° 330vdc capacitor. All appear to be electrolitic. My littlePeak LCR45tester could only check their capacitance using DC, they were all under 5% of their indicated values.From the research you inspired I believe these are intended to be used as 'start' (and filtering) capacitors.

author: Bakafish
author_rank: Contributor
timestamp: September 14, 2020, 03:14:38 am
content: I believe that this (or equiv) is the kind of unit you are suggesting?https://americas.rsdelivers.com/product/kemet/c274ac35100sa0j/kemet-10%ce%bcf-polypropylene-capacitor-pp-470v-ac-5/3778920

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 14, 2020, 04:50:26 am
content: Quote from: Bakafish on September 14, 2020, 03:14:38 amThat's one kind, but it's also common to find the kind that's in a metal can, for example this one:https://smile.amazon.com/MARS-Motors-Armatures-Capacitor-Micro-Farads/dp/B00CD75IPU/

author: Bakafish
author_rank: Contributor
timestamp: September 19, 2020, 06:31:58 am
content: I can confirm the motor run capacitor (Kemet 15μF，±5% C878BF35150SA0J) triggered the auto sense outlet asNiHaoMikepredictedBased on that result, I will create a much simpler setup that utilizes the 7A relay of the chinese remote module.Once built and tested I will upload a schematic and parts list for Googlers looking for a similar solution.

author: Bakafish
author_rank: Contributor
timestamp: September 19, 2020, 02:09:18 pm
content: Quote from: Philip Green on September 19, 2020, 10:22:27 amWill using the 7A mechanical relay provided by the remote module cause some issue if it isn't engaging/disengaging at the zero cross point? I'm trying to keep things simple, I have a zero-cross SSR, just seemed redundant if the mechanical relay is already over spec'ed for the purpose. My understanding is that a motor run capacitor should be able to deal with being switched in and out of circuit at any point of the waveform. Am I missing something important?

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 19, 2020, 02:16:57 pm
content: 15uF is tiny compared to the filter capacitors found in modern power supplies, so the relay shouldn't have any problem with it. If you really want to play it safe, add an inrush limiting NTC in series.

author: Bakafish
author_rank: Contributor
timestamp: September 25, 2020, 09:15:12 am
content: The Motor Run Capacitor being driven by the built in relay of the commodity Amazon sourced wireless switch module is working well so far. The final design is rather trivial, but I provide it here for anyone who wants to emulate it (do so at your own risk obviously.)I did try it with a small NTC I had in my scrap parts bin, but I think the current draw was too small to quickly get it up to temperature and it didn't seem to allow the cap to draw current, so I removed it from the system.Electrical Components:Kemet 15μF，±5% Motor Run Capacitor (C878BF35150SA0J)1W 37KΩ Resistor1A FuseGeneric Wireless Relay Remote Control Key Switch Receiver + Transmitter Fob12VDC-AC adaptorThe key variables are going to be the amount of current you need to simulate in order to trigger the auto-switch on your vacuum and the voltage/frequency of your country. The capacitor I list above works for my particular circumstances 100v/50Hz, which is not standard. An online "Capacitor Impedance Calculator" can be used to select an appropriate value for your needs. As has been emphasized multiple times in the thread, you must use aMotor Run Capacitorthat is designed to handle being continuously connected to line voltage. Do not substitute a motor start, or other type of capacitor, as they will likely fill your room with nasty smoke or other bad things™.The AC adaptor doesn't need to be 12V as these wireless switch modules seem to take a broad range, just make sure it is compatible.The resistor can also be changed, I used a beefy looking salvaged one I had, it needs to be able to handle the current and voltage of the capacitor you use. As stated earlier in the thread, it is there to drain the cap when it is not in use, so you don't get a nasty surprise should you somehow be exposed to it.I 3D printed a nice sturdy enclosure that integrated an inline (unswitched) outlet so my wired tools can still utilize the same automatic port without having to mess with disconnecting anything.I appreciate all the help and ideas from the community!

author: goldserve
author_rank: Contributor
timestamp: December 23, 2020, 11:46:45 pm
content: Im looking to make something similar for my Festool Midi vac here in the US. I bought the capacitor to try to see if it will activate the vacuum. Now i'm looking for an outlet box that has 2 outlets and ample room inside to capacitor and other electronics. Has anyone got any good leads on an outlet box with a short cord?

author: Renate
author_rank: Super Contributor
timestamp: December 24, 2020, 01:55:05 am
content: Get a 4" square electrical box with a single duplex outlet cover, a duplex outlet, a 1/2" knockout cable clamp, a 3' extension cord (that you chop the female off).P.S. I hate that capacitor idea, but don't let that stop you.

author: Bakafish
author_rank: Contributor
timestamp: December 24, 2020, 02:24:11 am
content: Quote from: goldserve on December 23, 2020, 11:46:45 pmDoesn't your Festool Vacuum have built in (or optional) Bluetooth module? Even at the cost, I think going the factory route makes more sense in your case. The Festool's are designed to have a remote, my solution is for vacuums that are not.Even if you want to make your own remote, I think it is much more likely that there is a convenient low voltage place where you can trigger the vacuum on that model since they likely have provisioned it to do so. IIRC there is a port on them for where the bluetooth module goes that should have low voltage relay terminals of some kind. Festool tends to be more open with parts access and schematics than other manufacturers, I would suggest posting more details about what you actually have and get some knowledgeable suggestions on how to solve your specific needs.Quote from: Renate on December 24, 2020, 01:55:05 amAs an update, mine has been working fine so far. I will of course update this thread if anything funky happens. I added some LED's to indicate line power and on/off state as the vacuums built in 5 second delay when turning off made it feel unresponsive and gave me more confidence in what it was doing. The key thing is to really use the right type of capacitor as stated many times before (as I shared your initial discomfort), and so I say again, if someone isn't 100% clear on what to use, they should not be doing this.

author: goldserve
author_rank: Contributor
timestamp: December 24, 2020, 03:57:54 am
content: I have the festool midi old version that doesn’t have by built in. I figured if I got the bt module and hacked a box together, I can reuse the module if I upgrade to the ct model vacuums later on.

author: Bakafish
author_rank: Contributor
timestamp: December 24, 2020, 04:44:14 am
content: Quote from: goldserve on December 24, 2020, 03:57:54 amI see. So your plan is to buy the current Festool Bluetooth receiver module and transmitter, and use those to switch in the motor run capacitor to the vacuums existing triggered AC outlet?I'd again recommend you tell us theexact modelof Vacuum you have so we can double check if there is a more direct path. If the controller on your vacuum is not encapsulated in epoxy you will likely have a lot better way of triggering this than the method I outlined.

author: goldserve
author_rank: Contributor
timestamp: December 24, 2020, 06:31:42 am
content: Yes, I have the older CT/CTL MIDI (pre-2019 with no BT module or expansion module). I do agree that accessing the low voltage control is easier to I took a quick peak inside the control panel area and it is quite well potted. There is also no room for me to drill a hole and install the BT button so the next step is to try to present a load like you did and make an external dual-output outlet that can also be triggered by the manual BT remote or the BT enabled batteries.I found this site which details the output of the Festool 202097 BT module (https://github.com/jenskueper/festool-ctl-sys-bluetooth). I will scope out how the signal differs between an ON vs OFF and I full expect to program some simple micro to switch in the motor run cap using a 5V relay. I already have a little 120V to 5V VDC module that is fully encapsulated that would be perfect for this.Thanks!

author: Bakafish
author_rank: Contributor
timestamp: December 24, 2020, 07:01:16 am
content: Okay, yeah it seems like your situation is the same as what I was solving. Any chance you can put the make and part number of your motor run Capacitor here so we can double check it won't release the angry pixies?

author: goldserve
author_rank: Contributor
timestamp: December 24, 2020, 07:21:43 am
content: Bought the same Kemet one you listed from Digikey. I actually got a 10uF and 20uF to see if the vac will activate or not. From quick calculations, the impedance is around 132-265 ohm @ 60hz.

author: Bakafish
author_rank: Contributor
timestamp: December 24, 2020, 07:29:10 am
content: Excellent! I had trouble with my first DC converter. It was a beefy looking unit, rated for 500ma but it kept flapping under load, which combined with the vacuum's 5 sec delay made figuring out what the issue was very frustrating. I ended up using one of my endless supply of tiny Apple iPhone chargers. They are really well built, have good output and are easily sourced.

author: goldserve
author_rank: Contributor
timestamp: December 30, 2020, 01:56:51 am
content: Just to give an update, I ordered the following from DigiKey for this project.27KWCT-ND FMP100JR-52-27K RES 27K OHM 1W 5% AXIAL102-PSK-5W-5-T-ND PSK-5W-5-T AC-DC, 5 W, 5 VDC, SINGLE OUTPUT1528-1738-ND 3191 POWER RELAY FEATHERWING1528-2126-ND 3403 FEATHER M0 EXPRESS ATSAMD21G18399-13892-ND C878BF35200SA0J CAP FILM 20UF 5% 470VAC RADIALFestool:202097I used a plastic enclosure from a previous project measuring 186mm x 146mm x 86mm and judging from things, I think all the components will fit very well. I already cut a hole in the top cover for the outlet but not pictured here.Progress so far:

author: goldserve
author_rank: Contributor
timestamp: January 01, 2021, 01:33:40 am
content: I finished the build and the video can be seen here:https://youtu.be/6hmbjQUKAuAThanks again Bakafish!

author: Bakafish
author_rank: Contributor
timestamp: January 01, 2021, 03:20:26 am
content: Good work!I like the clear cover, and a operational video is nice too. I didn't show internal or assembly shots of mine because it was an overpacked mess that would only confuse people. I made my case as small as possible with each component locking in the previous one and it was like Tetris getting it all assembled.