USB to DC cable, is this possible?

[nfsmaster]

I have been scouring the internet and have ended up here trying to make my own cable I guess.

I have an old digital camera, Nikon E2Ns, and the batteries for it are not the easiest to find. But I do have a power adapter for it, I have a charger and everything to make it work, but I do car photography and need it be a little more mobile and not plugged into a wall. The adapter puts out about 8V.

I want to make either a USB-C or USB-A 3.0 male to female DC cable. I want the USB side to provide the power to the dc port. and I know there are a ton out there, but this uses a dc plug that is 5.15mm x 1.7mm. I have already purchased a port that fits the dc part of the power adapter well.

I kinda know how to solder, but I don't know what type of cable or USB ends to buy. Or I looked and saw USB-C breakout boards, do I need one of those? If I go over the voltage will it hurt the camera, don't want to break this one.

Any help will be greatly appreciated. If more information is needed on the camera side I can provide links for manuals and some websites.

[ataradov]

If it actually needs 8V, then you will need a boost converter. There are a lot of them based on XL6009 and similar ICs on AliExpress and similar sources.

But you also need to check current requirements. Do you have the exact adapter model or full characteristics. USB port may not be able to supply the required current.

Something like this is even smaller and easier https://www.aliexpress.us/item/3256806193100891.html . Assuming the maximum output current is below the required value.

[IsmAvatar]

Yes, going over the camera's intended 8 volts would likely hurt the camera (likely pop a fuse in the camera, and then you'd need to find someone who knows how to open it up and replace the fuse, which is likely soldered onto the circuit board), You may be able to safely go a half a volt over or so, as they are built with tolerances.


USB-A is limited to 5 volts, so you'd need to further boost that with a boost converter (like ataradov suggested), which would probably be more infrastructure than you're looking for, and may or may not be able to meet your amp requirements.

Then there's USB-C PD, which is feasible but would also require some infrastructure. It can negotiate on preset voltages, with 9V being a common target, but 'negotiating' requires a device on the receiving end that can talk to the power supply (I'd suggest a "PD Trigger")... plus you'd probably want to drop that extra volt (a diode or two could do the trick, but you'd need to solder them somewhere *after* the negotiation device, but before the barrel jack, and make sure they're pointed the right way).

I believe USB-C PPS (programmable power supply) is what you're looking for. Not all power supplies support it though. It's also likely to be a board, so you would need to solder your dc plug's wires to it (and possibly come up with an enclosure to protect it). Typically they can be programmed with a trimmer pot (looks like as box with a screw on the side, turn the screw to adjust the voltage) so measure the voltage with a multimeter before plugging it in.

USB-C is powerful, being able to provide more current and voltage options, but only if the Power Supply supports it, and only if the cable supports it. Make sure you have a compliant power supply and cable if something is not working right.

Also, remember to verify the polarity of the dc plug.

[nfsmaster]

I have looked all over for specs on the adapter and I cant find anything. On the back of the charger it provides specs for what needs to be sent to the camera for it to work with the adapter and charging for the batteries. My wild guess is im trying to get the Camera section which is 8V 1.6A.

The picture provided is for the charger, and all of its specs.

[IsmAvatar]

Yes, looks like you need 1.6A. That rules out USB-A, which has a limit of 0.5A at 5V, and even less at 8V (P=IV, P_USBA=1.5W. 1.5W/5V = .5A. If you boost to 8V then 1.5W/8V=.3125A)

USB-C is still feasible though, as per my post above.

[nfsmaster]

I see, so there really isn't an all in one solution for this. Because I want to be able to run the camera on a portable battery. What would I need to be able to make this work on that? or what would I need to purchase or should I try to get a schematic made? are there people on here that can help with that?

[ataradov]

You need this https://www.aliexpress.us/item/3256804346467700.html configured for 9V. 9V would likely be too much for the camera, but this is easily solved by adding a diode in series with the positive output (anode to the output of the module, cathode to the camera). 

When you plug that module into a power-delivery capable power bank, it will negotiate 9V output.

[nfsmaster]

What type of diode should I get? I see a lot online, are there specific ones for just 1v? and what gauge of cable should I get?

Thanks for all the help guys.

[ataradov]

Any silicon diode with rated forward current of 2 A or more would be fine. Look for a diode with a forward voltage of 0.6 V or so. This would be the voltage drop this diode would provide. If Vf of the diode you pick is less, then you may need to use a couple in series.

This is not ideal way to drop the voltage, but it should be fine. The voltage drop is close to the rated at the rated current. At lower currents, the drop would likely be less, so you will get higher output voltage if you are measuring the power supply by itself without the load. The voltage would drop even more and it should be fine once you connect the camera.

[nfsmaster]

Thank you so much. I put some of those boards on order, but I found some with dip switches on amazon, would they work about the same or is there too much worry of the switches moving while in use? or could I get some to test all of this then when the ones come in I can put it together with less worry.

Also im looking through diodes, im assuming I need a through hole diode? and the ones im looking at have a Vf of 680 mV, would that drop it too much or would it be negligible?

[ataradov]

A link to what you found would be nice. Generally there is no reason for switched to move.

680 mV should be fine. Through hole would be better, since you are going to be soldering wired to it, but ultimately it does not matter.

[nfsmaster]

https://www.mouser.com/ProductDetail/Vishay-General-Semiconductor/SB260-E3-73?qs=u91jd7aysvMoA8RNuxeSiw%3D%3D

Sorry about that, I just wanted to make sure. as I don't really do this on the daily and don't want to fry this camera. Would you also happen to know what gauge of wire would be good for this?
---
Sorry I see you meant the board I found my bad.

https://www.amazon.com/ACEIRMC-Trigger-Polling-Detector-Notebook/dp/B0BTHXKM91/ref=sr_1_1?dib=eyJ2IjoiMSJ9.ql8FW-2LqfPtXkO4l6QMReiF14aY6YbdBa73kohOCHOzmDmU84H4ttmmeSMGTHgHbsaBL60LRIokGr6kf6IvSnd1tmrhYr9TSuH4nHeTzemwpDMAN5dP5fIfcm_d1y6lVRwRFl-XxX7jflxh3BW6Gt_t0h2-fOozFF3HvYqCu5rypMExjQ0xA4CRfWm3XdiN13amWVdo2nUuZuXIVDs9z8dm9RZD5mQpqOIZ66S-1A-C5lcd0IMuq8MfP23FVYXlUKtJftjTwCLxuU4voaitNVte1BPhzUqQIeHltLUFICc.yXlx0HXRAh9EIQZpH819t2yqVRQFNQf1fPXafeIU1mU&dib_tag=se&keywords=Type-C+PD2.0+PD3.0+9V+12V+15V+20V+Fast+Charge+Trigger+Polling+Detector+USB+Boost+Power+Supply+Change+Module+Charger+Board+Tools&qid=1721589964&s=industrial&sr=1-1

[ataradov]

The diode should be fine. And those switches have recessed sliders, it is really hard to make them switch on accident. It should be fine.

Any wire you can reasonably solder should be fine. 20 AWG and lower would work.

[IsmAvatar]

For 2 amps, you would want 18 AWG or thicker (thicker means lower number, so 16, 14, etc are all fine). Speaker wire would be fine.
The switches generally don't move too easily, but if you are concerned, just put a spot of glue on it after you've set them.

That diode looks fine to me, Schottky has a lower Vf, while you could also go for a regular diode such as 1N540x (like 1N5407) with a Vf of 1.0, but again, the one you've picked out seems to meet all your specs just fine. Through Hole diodes will be easier for you to solder.

You should also verify that your Trigger board is capable of 2Amps.

[nfsmaster]

Thank you guys so much for your time. Ill get to it and come back with results or question if something goes wrong, hopefully not frying the camera.