Parts Ordered for Internal, APP ON/OFF, Four USB Ports at 5.2 vdc, 3a!

[wkburkert]

I just ordered parts to take 24vdc from the P1S internal power supply to power four USB ports, each USB port 5 vdc, 3a. The 24vdc will be switched controlled using the AP board LED light connection and the OEM LED light will move to one of four USB ports. I will also add a new touch screen and riser LED’s and still have one USB available.

I think I have ordered all the parts and have wire, ferrules, and terminals but haven’t physically opened and look at anything but thought it might be a good time to see if anyone has some good reasons to not do it or if I missed something. While writing this I think maybe a fuse on the 24vdc line to protect the OEM power supply. Comments and questions are welcome.

[Olias]

This is similar to something that has been on my P1P bucket list. I look forward to seeing how you make out.

But I would also point out that your approach is fraught with peril not to say, about 5X more expensive than using a simple USB hub.

From the AP Board Wiki Page, that connector you’re point to is the DC Input connector for the AP board. Are you suggesting that you’re going to splice into it? I would consider that unwise.

Let’s be candid, all you’re building here is a 24VDC powered USB hub. If you’re going to build a USB hub at that location, then what advantage is there to using that when there is a perfectly suitable circuit-protected USB power port less than 5cm away? I don’t see any advantage to that approach but I do see lots of jeopardy to tapping into input power.

Please educate me if I am missing something.

Instead, why not consider buying an $8 hub and breaking it out of it’s plastic and then printing a bespoke enclosure to fit your needs? It would be a lot safer, faster and cheaper.

Alternate Approach

Summary

NOTE: I have not built this myself as of yet. So do your homework before going down this rabbit hole.

Another possibly more safer approach, which I was considering experimenting with for my own project, might be to use either a buck converter or step down transformer which has built-in circuit protection. This is far safer.

The Meanwell LRS 100-24 Power Supply that BL uses appears to have at least one rail that isn’t be used.

Terminal 6 looks like it is unoccupied. (taken from the Bambu PS wiki)

Therefore it is available for use as an auxiliary power port. Put even if you did have to splice into another circuit, I’d do it from the power lug not from the end of the AP wire, that you suggested above, who’s resistance is unknown. That lug is also circuit-protected so you have added peace of mind.

Uctronics makes a device that I’ve used for other USB projects. I used their competitors products also that I found for $10 for 5 each off of Ali Express.

Amazon.com: UCTRONICS DC 9V 12V 24V to DC 5V 5A Buck Converter Module, 9-36V Step Down to USB 5V Transformer Dual Output Voltage Regulator Board [2 Pack] : Electronics

These can be found all over the Internet. The fact that it also supports a barrel connector for external power supply was a nice-to-have when experimenting with a design. In the last application I used this, I was building an Arduino li-ion battery analyzer. This device allowed me to keep the circuit isolated from the device while I was building it which made current draw measurements a lot easier. The benefit behind measure current draw is that it will aid in understanding if you are pulling too much power out of the 5VDC.

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Suggested tools for this project

Summary

Also, do you have a USB power meter in your tool kit? I found these to be way too useful for diagnosing USB power issues and a necessity when verifying a design or just diagnosing suspicious USB behavior. Note, I am not an EE and these are so easy to use, you don’t need to be an EE.

I’ve got six different variants but this UMC25C below is one I’ve had for over five years and is sort of the grand daddy of them all. If you’re doing any kind of USB power design or diagnostics, this tool is indispensable. They come in a Bluetooth version so you can chart power draw on a laptop or Smartphone. At $15-$35, they are too cheap to not have more than one.

Do an Internet search under UMC25 or UMC24, you will find dozens of these by different makers. Also, YouTube search on these because there’s likely better alternatives today. Rui Deng I believe was the first one to introduce this but all that’s behind this is a the same MPU you might find in an Arduino. So they are real cheap.

I purchased this one last year for $70 and still have a little buyers remorse. It supports PPS which is what I needed and it has built-in power analytics, is made of metal and has a very nice graphing display. But truth be told, at 3x - 4x the price of a UMC 25, it was more fluffer than nutter.

[Sibes991]

i use almost this same one for that purpose. powers the 2 sets of LEDs, the wyze camera, and the Xtouch esp32 screen on my P1S, all from the USB hub

[philch]

What wkburkert is attempting is a lot safer than any suggestion to use USB hub, splitter on the provided USB terminal or any other solutions using the USB or the led connector on the AP board for extensive power.

What I understand is that wkburket wants to use one of the available 24V supply from the power board, use a voltage drop board to 5V for 4 USB outlets. He will only use the JST GH 1.25 connector on the AP board to trigger the relay he showed. This relay only needs 5mA on the trigger side well below the about 300 to 400 mA required for the original LED.The power side of the relay will be wired to a USB output with the contact powering LED. Rest of USB to power whatever he needs.

I’m sure the board he showed can carry more than 1.5A per port (he says 3A actually) whether a USB hub is generally limited to 500mA per port, these hub are really meant for data not power.

Xtouch would be about 200mA and 300mA peak, Wyze camera 400mA peak, 2 sets of original LED about 600mA to 800mA (more if third party), Sibes991 you may be just below or at the max provided USB rated at 1.5A and I did not account for the hub consumption itself, have you measured current usage of each of your outputs to make sure you’re OK?

wkburkert just check the max rated current of the USB board you showed is well within the power you want to extract from each port, is it realy 3A per port or 3A total?. Also check that if you use the AMS you’re not overstressing the power board adding extra components to it although I’m sure there are plenty left.

I myself use the same relay just to have a 6W LED (1.2A) connected to the power output from the provided USB port but keeping the light trigger switch active, as you are planning, I connected the trigger side of the relay to the AP board led connector.

You say you will connect the LED to one of the USB port, I think you mean you will connect it to the NO side of the relay while powering the input (COM) to one of the USB output of the the USB board, right? The USB board will not need to be triggered by the relay but always on as long as the printer is ON.

Some pieces of advise, the AP board connector is a JST GH 1.25 not a mini JST 1.25 (or molex picoblade 1.25 which is the same), the trigger side of the relay needs + and - from the board connector but for it to work you need to either strap - to IN or + to IN on the relay board (I used - myself and I put the jumper on the board for the low trigger side). To make things more practical, isolate the NC output by cutting the NC path from the relay so you can use that terminal to wire the negative side of the USB input and then connect on the same terminal the negative side of the LED otherwise you will have USB positive input to COM, LED positive to NO and negative from USB direct to LED negative, with cutting NC path you can have 2 wires going to the relay and 2 wires coming out for the LED which would be easier for wire management.

[Sibes991]

yup it never draws more then 1 amp

[philch]

You’re good then

[wkburkert]

I’d like to 1st say thank-you for your kind words and understanding my goal. I have some questions that I hope you can answer. The 24vdc to 4-port USB board I purchased I now suspect is not what I need because it does QC3 fast charging and i think it can output more than 5vdc. I think I need a Buck converter where input voltage is DC 9v-36v and output voltage is 5.2V (5V-5.3V available according to your input voltage). I would use four of these.
I keep getting lost looking the AP board 2-pin, JST GH 1.25 connector. Might you know of a source that would come pre-wired? I can find kits of connectors but need a few 2-pin pieces.

[philch]

If you go amazon, I could not find single GH connector but only a full box of them at high price. If you go aliexpress and don’t mind the shipping time you can find it at very low price. Other solution is to simply desolder the end of the original cable from the led strip and then rewire to the relay, you could still reverse later resoldering the original led if needed.

For the buck converter, I never used the type you showed although it receives good feedback on amazon or aliexpress but I find it flimsy for the task. I use the type below, may be it is exactly the same inside the case but I would feel more confident if it was my machine. I have one permanently installed in my car to drive my dashcams, one also attached to the power supply of my milling machine to drive my DROs and never had any problem with any of them, stable voltage, no heat, no interference with the digital scales of the mill. They exist in 15, 20, 25W and more. Depending on the seller, you can find them with 1 USB or 2USB out or simply open wires that you can connect directly or use USB breakout boards if you wish of any type (usbA, mini, micro, usb-c) for a clean installation or JST outputs boards also for a smaller footprint.

Greluma 1 Stück AC 12V 24V zu DC 5V 5A 25W Abwärtswandler, 10-28V Eingang AC-DC...

[matty.lad]

Let me get this right, the OP wants to be able to take upto 12 Amp from the P1S power supply?

Surely it was not designed to be able to do this and such use may harm the operation of the printer by taking some of the current that was designed for printing purposes.
I would recommend that you seek an external PSU for this task if you want such high current outputs.

Consider external 5V supply and a multiple USB output board that uses the internal LED connector to switch them on.

[sardelich]

the outputs are up to 3amps, total consumption will be much much less

[matty.lad]

Yes but “upto 3A” means that upto 3A for each can be drawn, I suggest that they should be far far less than that.

This Wiki page also suggests that taking power from the AMS is also a potential issue.

Bambu Lab Mods to be cautious about

[matty.lad]

I have recently found that the USB output is capable of 1.5A.

[wkburkert]

There is a need for more than one USB port - OEM LED light kit, riser LED lamp kit, touch screen, spare usb.

[jRobin]

Hello, the information for the connector JST GH 1.25 “not mini” is very good. I bought the wrong ones some days ago. But I cant find a source for the normal JST GH 1.25.

Is there any source (ALIexpress, Amazon, ebay) that you can share? Thank you.

[philch]

Actually, if you search for JST GH 1.25 on aliexpress, you will find many available (no such luck on amazon unfortunately). Each seller generally sells 2 to 6 pins or more connector types, make sure you select “2 pins” or “2P” in the options before clicking purchase :). Here is one example:

https://fr.aliexpress.com/item/1005005767460572.html?spm=a2g0o.productlist.main.27.61b71afffQJQmQ&algo_pvid=82a8748f-db67-4285-b037-52d513e65f28&algo_exp_id=82a8748f-db67-4285-b037-52d513e65f28-13&pdp_npi=4%40dis!EUR!1.52!1.43!!!1.61!1.51!%40211b813c17063299693092273e544a!12000034279530805!sea!FR!167704693!&curPageLogUid=pKj7qVdhGCxd&utparam-url=scene%3Asearch|query_from%3A

[user_3490374403]

Amazon USA has lots of these type connectors listed and available…

[wkburkert]

thanks but I am way past the design at this point and just waiting on two fans to arrive. I’m now going with the ‘Air Scrubber’ vs Bento Box because the design is well thought out top to bottom while based on the Bento Box.

[akikiki]

Impressive idea. I admire this type thinking.

I’d like to add two comments. The simple one first. Sonoff makes a small plug they call the Micro. 5V Wifi plug one male USB A, one female USB A/B (I guess). In and out. It has a very small side switch you can use for on and off. But the best part, its Alexa and Google Home Asst supported. So you can talk to it. I use them on stuff. Also app/automation/scene supported and Alexa routines. Its about the size of a quarter, well, stack of quarters about 1" high. $10 on Amazon. Also available on itead.cc I use their WiFi plugs to turn my P1S on and off too.

Second. There’s an engineer on esty, goes by 3dMachinst. He makes and sells a variety of “boxes” that use the 4pin and 6pin cables to tap power from the printer. Boxes mount outside the printer, and cables pass through his boxes. You can select from 24v, 12v, or 5v combinations. Example his AMS on/off switch powers AMS because two cables pass through it. Works GREAT ! Saves unplugging.

I am adding LED light strips to my AMS. Using one of his boxes from AMS 6pin to two USBs. 5v. Will mount his box on the left side of bottom with command strips so I don’t have to drill holes.