Hoping to Hire Someone for a Custom Electronics Project

Hi there, so first off I’m a longtime fan of the maker community and I’d most likely be a dues paying member of VHS by now if I didn’t live on the coast and it was a ferry ride away. As much as I like to tinker and build stuff (mostly 3D printing and carpentry) in my spare time though, I’ve got a project that’s just a little outside my skill ceiling I was hoping I could perhaps hire somebody to help with.

So the project is I have this unique watch that requires a special proprietary induction charger to top up the internal battery. Unfortunately it’s not a standard Qi charger or else this would be a lot simpler. The charging base, wall plug and the cable between them are all larger than you might expect and kind of a hassle to pack around when traveling light. For a couple years now I’ve been dreaming about hacking together a more streamlined solution. The idea I have in my head is to take the charging base and the wall plug and combine them together into a single plastic housing with a USB C port on the side so I can just use a single cable and a portable battery or a cellphone wall charger.

I’ve never hired anybody for a job like this before but I’ll pay any and all labor/materials whatever it takes, so if you or anybody you know might have the soldering skills and be interested please let me know and lets see if we can make something cool out of it.

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Hi Hightide! Can you post the model of the watch and/or the charger and maybe a photo so people can figure out if they are equipped to take this on?

I might be able to help you, possibly, depending on how weird this tech is.

Sure thing, I made an Imgur link for the charger and wall plug but I wasn’t sure if the link would work here when I was first writing my message but I’ll drop it in here Imgur: The magic of the Internet as for the type of watch it’s called a Devon Tread 1

It just occurred to me that I should have included a picture of the specs on the wall plug so here’s an update with that. Imgur: The magic of the Internet

Are you sure it’s not a Qi charger? When was the watch released?

It’s a complicated subject, but Qi unfortunately not only stipulates the electrical behaviour, but also the size of the coils and minimum output power - meaning you can have a charger that is electrically compatible with Qi but uses smaller coils and/or a lower output power, so can’t be called a Qi charger. It’s not necessarily as simple as just replacing a large coil in a Qi charger with a smaller one, but often that does work. Of course, especially if the watch is quite old, they could’ve rolled their own solution or they may very well have used a standard other than Qi.

If all you need is that charging dock hooked up to a 5v to 12v boost converter with a USB port attacked, that would be pretty straightforward.

You just need this: https://www.amazon.ca/Eiechip-Voltage-Regulator-Converter-Module/dp/B07RNBJK5F

Which has a micro usb input and adjustable output.

The issue with this is that we are not sure if your device actually needs 1A current (12W total power), because it’s hard to find a USB charger that goes above 2A (10W power), factoring in the conversion losses, you’d only be able to get around 8W of power delivered to the hub, whether that is enough or not, you’d need to measure the power draw during charging to find out.

I don’t think I was very clear there, IF your device only needs 5-8W of power during charging (not the full 12W supplied by that adapter), then the solution above would be trivial, if it does need 10-12W to charge, then charging it with USB might be tricky.

If you do need the full 12W, and you have a USB-PD power supply that can deliver 12V, you can use a ZYPDS or ZY12PDN module to trigger the supply to produce that voltage and just wire it directly in to the existing cable, or via a step-up converter.

12W 5V USB ports are pretty common these days too (‘2.4A’ ones on chargers) so it may not be necessary.

It’s very unlikely that it consumes anywhere close to 12W though, a watch is going to have a small battery with a small charge rate, and even with incredibly inefficient power transfer I can’t imagine it’s more than a couple watts.

Clearly I was mistaken about the limits of USB power. Thanks for the info about USB-PD, @ktims, always interesting to learn about the speccs of new tech.

@Hightide if you are willing to solder 2 wires and 3D print an enclosure, then you can do this on your own!

The first iteration of the watch came out in 2010 and this is just a guess but I have a hunch they’re using the same tech now to charge the watch as they did back then. Another thing that tells it’s probably not Qi is the fact that the back of the watch that’s in contact with the charger is definitely not plastic and I don’t think it’s ceramic either so they probably had to make their own custom solution to play nice with the metal body.

I also would be highly surprised if it ended up using the full 12W it says on the sticker. Of course there’s no way of knowing without plugging it into a wattage detector but I may have one sitting in a drawer I could use to find out.

Thank you very much for the vote of confidence, while I’m pretty sure I could 3D print an enclosure I’ll be the first to admit I’ve never touched a soldering iron and if I were to botch the job I’d wreck this proprietary charger and have to ask the manufacturer for another one and the cost would be the same as paying someone for a days work anyways.

Thank you very much for the technical details and wattage info though, I’ll try to find out more about how much the charger actually draws from the wall.

A while ago I got a Wear24 smartwatch for my wife (Verizon branded, ebay), It seemed to support Qi but in reality there seemed to be exactly one charger that would work with it, and your power supply could not exceed 1A or the charger would melt down. My lesson with it was that Qi at least as of 3-4 years ago was still the wild west.

If you are not comfortable doing the soldering I would be happy to do it for you for a small fee. It would take all of 10 minutes to strip the leads, find the polarity, and solder the contacts to the boost converter. I can even give you a quick soldering tutorial if you wanted to try your hand at it in the future. Good skill to have.

Designing and printing an enclosure would take significantly longer, but if you need help with that I would be happy to. I am free most Sundays around noon.

Although clarification: you really cannot screw this up badly enough to destroy anything but some wire (which you have plenty of), as long as you do not hook up positive and negative backwards/supply the wrong voltage, all of which is easily checked with a multimeter before you begin.

But if you are still not comfortable doing it, let me know.

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I hear ya, the first Qi charger I ever bought for testing purposes was off AliExpress back in 2014 and it barely worked with anything. I’ve had nothing but success though with all the Samsung Qi chargers I’ve ever bought.

Sure I’d be very happy for the assistance, especially if you’re capable of designing and 3D printing an enclosure. I’m pretty decent at printing projects with my own machine but I’ve never been very good at designing my own 3D models from scratch. If you have my email we can move the discussion there and see if we can work on a design.


Sure I’ll send you an email!

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