Ask HN: How do I get my own health tracker manufactured? | Hacker News Reader

Ask HN: How do I get my own health tracker manufactured?

Hey HN, question.

I have been wearing wearable health trackers (think fitbit) for a little while and have been thinking about what I would like to see in the next one - but that never comes out (actually wanting less).

It got me thinking - is it possible to have custom hardware manufactured?

I would love to make a wearable health tracker as an open source project. I can write the OS and basic sensor interpretation but acquiring the hardware to do it is challenging.

People talk about hardware design and manufacturing in China, is that accessible?

How would one even approach this? Is it even a realistic goal for a normie?

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Yup, I'm a 'normie' and I just sent my third project this week to JLCPCB. Paid less than 100USD for PCB production, assembly, and shipping.

After a few back and forths on a given board to iron out any kinks, I have a set of design files they (or anyone) can produce in any quantity for a reasonable price.

The hardest part for me now is mass-producing custom enclosures... I can design an enclosure and get it 3D printed easily enough, but I often stumble trying to make it ready for injection molding (geometry is usually too complex... and draft angles...) I've found a happy medium by using off-the-shelf enclosures and following the manufacturer's guidelines for how to fit the PCB inside.

But sometimes you need something a little smaller/cheaper/blue-er...

I used to teach a "Transform your Arduino Prototype into a Mass-Market Product" workshop :) I suggest starting with creating a PCB https://learn.adafruit.com/making-pcbs-with-oshpark-and-eagl... . Helpful shortcuts for when you are further down the Eagle + JLCPCB route https://github.com/oxullo/jlcpcb-eagle and https://github.com/Combinatix/JLCPCB-Basic-Parts

It's easier than you might think! These days it's pretty easy to get low volume circuit boards made. Then, with a cheap 3D printer, you could make plastic cases (or plastic molds for silicone bands, etc.).

Check out https://tindie.com/ if you want to be inspired by other makers.

My first guess:

- find the sensors you want on Digikey or similar

https://www.digikey.com/

- design a PCB for those; everyone has preferences, but here’s some common choices

https://www.raypcb.com/online-pcb-design/

- get that PCB manufactured, eg at OSH Park

https://oshpark.com/

- solder your parts onto that board

- model a housing; get 3D printed

Congrats — you have a prototype!

You can do all of these steps through free tools or moderate fees; people can and do design their own electronics this way.

For producing electronics you can certainly contract out the design and manufacturing of boards. There's countless freelancers and entire contract design companies.

From there, it depends heavily on the number of units you want to produce.

For a couple hundred units per year, you're assembling things by hand. PCBs are shipped in complete, you put them in the case, test, package, ship. Cases will probably be 3D printed, which you can either do at home or contract out to a 3D print company. Designs can also be contracted out.

In the low thousands you'll be looking at having things hand assembled in a factory somewhere. Your housings and components are shipped to the assembly house, they do the manual labor of assembly, programming, and testing depending on how much you spend.

At this level, injection molded housings become more economical than printed, at the cost of a big upfront investment.

From there, you're into industrial quantities and I personally don't know how to get there, so good luck!

If you're really serious and have the money to front it, find a design consultancy. Their entire business is assembling and renting teams of skilled engineers to solve these problems for you. Or, build a startup company and hire a couple of nerds in a garage.

The root of your question is "how do I do this thing without all the skills?" and the answer is to just hire people with skills.

Consider a PineTime, it might cover 80% of the functionality you need. Develop the essentials on that, and then consider getting a bespoke design.

Just my two cents though, I don't know what your needs are.

I don't know, but I would like to and I also feel like there is a real opportunity for "open" hardware or whatever you want to call it that is accessible to a layperson. I want a new running gps, and it seems the options have really closed off over the years as far as just being able to get a normal gps that tells you your speed and kilometers and isn't "connected" in some way.

The same is true all the way up e.g. to cars. Electronics are now a vector for stealing personal information, instead of an actual product to sell. I'd love to be able to reclaim that and have stuff with basic functionality I want and none of the crap that's there to serve the vendor only.

The hardware is the hardest part (hard to hear as a SWE, i know). But there are contract shops that can design your hardware for you and have it made. Prepare to pay 5-6 figures (regardless of whether you want 1 or 10,000 made)

You can attempt to do it all yourself, but you'll never pass FCC or any other cert (so you cannot sell), you're unlikely to make anything small enough for daily wear (past showing off), and forget waterproofing

(these are all examples, some makers really are good enough to do all of this, but then again those are not asking for "how do i do it?" on HN)

You only need FCC certification if you design radio circuits yourself. You can just use off the shelf modules which carry their own certification. Some are plenty small enough to include in a wearable.

False, if you intend to sell. Modules do not provide full-device certification

I helped design and have manufactured a smartwatch style health tracker as part of a research project:

https://amulet-project.org/

It cost somewhere around $200-$250 per watch in a quantity of 150 five years ago to have them made and we did final assembly (putting the PCB into the 3D printed case) ourselves, as well as testing. The MCU was an MSP430, there were a variety of sensors, microSD card, USB charging, an e-ink display, a Bluetooth LE radio that talked to a smartphone and external wireless sensors, and touch sensitive buttons/slider. This is the company that built them for us, I'd recommend them:

https://www.emeraldems.com/dataed/

They can help with design also, though I've only used them for manufacturing.

The software is available here:

https://github.com/AmuletGroup/amulet-project

Note that because the radio chip is often revamped the one we used is now obsolete, which also obsoletes the radio firmware. Some of the other parts have also become obsolete (chips go obsolete fast!)

That said I'd recommend hacking an existing smartwatch instead, they are really cheap and it is easy:

https://hackaday.com/2021/07/08/reverse-engineering-a-very-c...

https://hackaday.io/project/144350-hacking-wearables-for-men...

https://hackaday.com/2018/05/04/hacked-fitness-trackers-aim-...

https://hackaday.com/2018/05/29/hacking-a-fitness-tracker/

Designing your own system and board and making it reliable requires a lot of special knowledge. For example, did you remember to add anti-static protection diodes to all external electrical I/O? Does your battery management keep the battery from discharging to too low a point? If you have more than one MCU how to you synchronize them? How do you keep accurate wall clock time/date? How do you get data on/off the device? Where should you put test points on the PCB? What connectors are reliable? Does your Li-Poly battery need a protection circuit? Do you need it to be waterproof?

So designing something close to a product is not easy. It took us years and several very different prototypes and the end product was still a prototype (no waterproofing for example and not impact resistant). If you're just doing this for fun and are ok with something less polished or are interested in building a prototype, then by all means try designing your own, it is not too hard to get a working PCB and design a 3D printed case for it. You can find several examples of people making their own smartwatches on HackADay.com which might helpful.

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