What follows is a brief chronicle of how I spent the last few working months building 160 Frog Sensor Kits in my apartment. If you are interested in mid-scale manufacturing, bootstrapping a hardware manufacturing project, or just general stories about how I built this, you might find this interesting.
Perhaps some aspects will be too technical or detail oriented to be broadly interesting, but hopefully, it is useful to provide a case study on the challenges associated with hard tech and building things in the physical world, especially as a small team of basically one person.
The Beginning
Around the beginning of this year, I had an interesting phone call from a large company that had seen our sensors at Ribbit Network (the non-profit I started to build open-source GHG monitoring hardware and software). They wanted to purchase 250 sensor kits to build as part of the yearly corporate summit they host and then distribute those kits to science educators around the country. The opportunity to create that much impact and get that many sensors out in the world seemed too good to pass up, so of course I agreed, without any real concept of how I would get it done.
The Plan
The first priority was to ensure I could actually buy 250 of all the critical parts I needed. After checking the stock of a few key components, it became obvious that 250 was not going to be possible by March 1st. Chatting with the company hosting the event, we agreed around 150 would be reasonable. Eventually, this number would go to 160 after some sample units.
So I sat and waited for the payment to come through so I would have enough cash on hand to make the bulk purchases of the electronics. This part was interesting to me because my past experiences in venture-scale companies usually meant we took a different tactic. Speed was always of the essence, so you would spend other people’s money (the investors) to buy the parts ahead of time so that you could fulfill the order as soon as it came in.
Buy the Parts
Once the check cleared, I frantically scrambled to hit “buy” on all of my saved carts and PO emails. This is when the challenges began.
I had confirmed with any of the single-source component vendors that they would have enough stock to fulfill the order when I placed it a few weeks ago. Unfortunately, the thing about most parts vendors, is that you can’t really be sure of what they are telling you until you have received the parts that you bought. It seemed I could only buy about half of the cellular communication modules that I needed for this order.
Engineering is like putting together a big puzzle. Electronics are selected, an enclosure is designed around them and seemingly arbitrary initial decisions become somewhat binding (this piece has to fit in this space). Given that the whole design and software were already finished (we just spent months converting our code to micropython), I did not want to go back to the blank sheet and redesign everything. So I spent many nights and several weekends frantically designing a size and connector-compatible replacement PCB for the cellular module.
Through many nights of little sleep and a lot of luck, I was able to produce a functioning PCB that successfully connected to the cellular network. The final order was delivered only 3 days before the workshop and if one additional thing had gone wrong, it wouldn’t have been possible.
On the plus side, this was an excellent excuse for me to finally finish a real project in kicad, an excellent open-source PCB design software.
3D Printing
Now the only parts remaining were the enclosures. In the Frogs, I’ve built myself, and I have always 3D printed the enclosures out of recycled PETG. 160 is an awkward number of things because it’s not yet cost-effective to injection mold as this usually doesn’t make financial sense unless the order quantity is 500 or more likely 1000 pieces. However, it’s a LOT of parts to 3D print. Printing the full set of parts for the Frog sensor usually takes about 12→13 hours if you have a decent printer. That’s almost 2000 hours of printing not including extras or print failures.
One of the Ribbit Network Core Team members contacted almost 20 3D printing vendors to find one that could fulfill this order with recycled plastic. This is not a common request and most vendors rejected it outright saying they don’t work with recycled materials, which was a bit disheartening for the industry in general.
However, we finally found a small business that agreed to take on the order. They sent us a few initial samples which looked great and we hit the go button on the order.
A few weeks later we started hearing some bad news from the vendor. The quality of the recycled filament they started receiving was not very good. There were huge variations in the thickness of the material, which causes lots of issues for the printers.
After a lot of quality issues and negotiating with both the filament company and printing vendor, the printed parts started to arrive. This was also the moment when I started to conceptualize how many kits 160 was and if I would have room in my small apartment to get this done.
At this point, we started to notice a few quality issues with the parts we had received as well. By going with a small business that would agree to print the parts with recycled material, I knew there would be little to no mature quality process from that vendor, but keeping the sustainability for this product was more important. Now I would pay the price.
Many of the parts had huge cracks which means that myself and another volunteer spent several weeks frantically printing replacements on our printers to get enough parts as we couldn’t rely on the vendor. The volunteer community of Ribbit saved me here. Without them, I would simply have not had enough hours in the day to get this done.
Packaging Selection
Given that this project is entirely for climate education and information, I wanted the packaging to be as sustainable as possible. This proved to be quite difficult. There isn’t a lot of information and resources on how to package a product most sustainably.
Ultimately I settled on 100% recycled cardboard boxes that could then be recycled after the event. We packed all the little electronic parts in some compostable sandwich bags.
This isn’t the ideal solution in my mind, but lots of work needs to be done here to figure out the most optimal solution for sustainable packaging of electronic goods.
Assembling the Kits
If you have never worked in an assembly line it’s hard to describe what it’s like to put together this many of something. Even though this was a kit, not a finished product, there were still at least 40 steps I had to complete to test and assemble all of the parts. This work probably took me a week straight working 14-hour days.
Success!
Through an amazing combination of hard work and sheer luck, all the kits arrived at the event and everyone had a blast assembling them.
I was elated seeing the months of hard work come together in this one event and even more excited thinking of the educational ripple effects these sensors will have once they get into the hands of educators.
In Summary
Wow, that was a ton of work, but I loved doing it. It’s always been my dream to work on open-source hardware and I’ve been lucky enough to make that happy now.
I don’t have any regrets about building these sensor kits myself because I really don’t think there was another option available for a bootstrapped hardware org. I think that this reveals that there is somewhat of a gap in our hardware innovation ecosystem that really only allows people of privilege to actually ship hardware. You either need to raise a lot of investment capital or be somewhat personally wealthy to allow yourself to bootstrap it, neither of which is very accessible to everyone.
If you are interested in the design of the Frog Sensor you can see all the information here.
Hopefully, soon I will figure out a funding source for Ribbit that will allow me to hire a manufacturer or find an office for Ribbit sensors to avoid the “manufacture in your apartment” scenario again.
Thanks for reading. I appreciate you.
Have any questions? Let me know in a comment via the button below:
I am also on the hunt for my next consulting role. Consulting allows me to keep myself personally funded while I pursue open-source solutions for climate. If you or anyone you know are interested in hiring me for help on the engineering or engineering leadership side, please reach out. Thanks - Keenan