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A DIY kit for a solid-state Tesla coil that plays music, shoots 2-foot-long sparks, and teaches you electronics.
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oneTesla

928 backers pledged $169,155 to help bring this project to life.

Get your SD card interrupter now! Can you help us make it to Bluetooth support?

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Hey Coilers! Want to play music on your oneTesla without a computer? 

Since our tinyTesla/oneTeslaTS campaign hit the stretch goals, we’re excited to announce the addition of an SD card interrupter kit compatible with your coils! They’re only $59, including domestic shipping, for the duration of the campaign. 

We also added a super-stretch goal: at $400K we'll add Bluetooth capability to the interrupters as well! It's up to you to help us make it there. 

The SD card interrupter will let you store MIDI tracks right on the interrupter itself and eliminates the need for a connection to a computer. The new interrupter is compatible with the original oneTesla kit as well as the oneTeslaTS kit. 

Get your place in the queue for the SD card interrupter, oneTeslaTS and tinyTesla kits now!

Two new products thanks to you!

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Dear oneTesla backers,

We have very exciting news. After getting feedback from hundreds of you who had built our original kit from this Kickstarter campaign, we designed two new educational Tesla coil kits for you. And now we are proud to announce the launch of two new Tesla coil kits: tinyTesla and oneTeslaTS.

Many of you expressed interest in a smaller, easier-to-build Tesla coil, so we developed tinyTesla, a little singing Tesla coil that can fit into your hand. This kit is specifically geared towards beginners, so anyone with basic soldering experience can build it.

tinyTesla
tinyTesla

We also took your suggestions to heart and designed oneTeslaTS, a re-spin of the original oneTesla kit that many of you got as rewards in our first Kickstarter campaign. Some of the features that distinguish oneTeslaTS include:

  • Etched primary coil-- no more coil winding!  
  • Screw-together PCB chassis with silvered text 
  • Ease of IGBT replacement: the heat sink forms the base of the Tesla coil, and the IGBTs are mounted on the underside of the main board.
  • Emphasis on robustness and portability: you can pick up the Tesla coil by its toroid, and the hardware is easy to disassemble as well.
  • Designed with kitting in mind-- efficient production needs to start at the product design level.
oneTeslaTS
oneTeslaTS

A lot has happened at oneTesla since the launch of our last Kickstarter, but we hope that all the knowledge we’ve gained along the way will bring you better educational projects! Check out the Kickstarter page for our two new products and see what you helped create.

1-Year Anniversary Mega-Update (Part 2 of 2)

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Dear Backers,

In part 1 of our Mega-Update we talked about some logistical considerations for fulfillment. Now we’ll cover a little more about design, sourcing, shipping and other things to think about when starting a hardware project. 

Packaging 

We decided to pack the parts directly in the shipping box, to not need a separate product box and shipping box (take a look at the picture at very top of the post). If we were to do it again, we’d have a separate box for the product and for shipping after all. There were many backers who requested something extra with their kit, such as an extra board. It wasted time to cut through the packing tape on the box to put in the extra item when the shipping labels were printed, or to have a pile of finished but untaped boxes waiting for packing labels and a list of extra parts. 

Minimize loose parts in a box. We improved upon small parts packaging over time, so the final kits have no loose bits floating around. If you’re just starting out, get a variety of boxes and plastic bags and play around with them to see what works best. USPS will send you free flat-rate boxes if you order online. 

Isolate sharp corners using bubble wrap, boxes for individual items, or pointing the sharp thing away from delicate items. 

Measure packaging time and costs. We anticipated that with time, our packaging workflow would get faster, but it turned out not to be that way. At some point, your assembly line just can’t get any more efficient. No matter which tricks we tried, in the end each of our kits takes over an hour for one person to assemble from start to finish-- that’s excluding QA, troubleshooting help, “it got seems to be lost in the mail” questions, printing shipping labels, unpackaging parts from reels, etc.

Product Design 

Think about your manufacturing process while you design your product. In our case, the manufacturing process is kit assembly, which involves many steps: cutting and coiling wire, cutting apart parts reels, inserting chips into foam, heat-sealing parts bags, wrapping chassis in bubble wrap, etc. The number of steps needed to complete a kit, and the large number of components in each box, poses challenges for efficient packaging. 

  • If functionality is not compromised, minimize the number of components by using multiples of one size/type. Use ten of one screw instead of two each of five different screws, for example. Don’t use three 910 ohm and two 1.2K resistors if five 1K ohm resistors do the job just as well. Little changes like this really add up. 
  • Don’t use both standard and metric hardware; you’re just begging to get them mixed up. We often confused #4-40 screws and M3’s. Metric hardware probably preferable, as it's cheaper in bulk from China, plus kit builders outside the US can find replacements for it. 
  • If possible, plan ahead for a QA process. Quality assurance has been an issue, because there is no easy way to check over every small parts bag for accuracy. Omissions or mistakes are frustrating to the end-user, and consume our time when we have to make a second shipment for missing parts.

Every custom part is a liability. While you should use off-the-shelf components whenever possible, eventually you’ll need to make some custom parts. Your pre-launch plan should pay particular attention to them.

  • Ensure your manufacturer has specific experience in the process you're using. You’d think that our stamped metal toroids, for instance, would be an easy to make. The manufacturer thought that too, until he struggled for eight months with centers popping out and the toroids having wrinkles because he did not have specific experience with metal stamping. Now, because the first shop has jacked up their prices, we've decided to go through a lengthy and costly process of re-tooling with a spinning house.
  • Low price can mean low quality or reliability. We had to go through three different chassis manufacturers so far because we kept having problems with them: too slow, too expensive, poor quality, “there was a fire in the laser cutter.” Laser cutting ⅛” acrylic should be a fairly standard and low-risk procedure, but we found price quotes to vary immensely. When you’re looking for the lowest price possible, keep in mind there's a good reason why some places are a lot cheaper than others. 
  • Completely specify your part from the beginning to avoid any ambiguity. The secondary coils suffered alarming issues when the manufacturer switched from signal build wire to heavy build wire of the same gauge, thinking it wouldn't make a difference. Heavy build magnet wire has thicker enamel, so a fewer turns will fit into the length of the secondary, thereby changing the inductance and the tuning point of the coil. Fortunately, we were able to work with him to figure out what happened. (Note: if your secondary is under 228 ohms, the simple fix is to use 5 turns on your primary).

Sourcing Components

Streamline your supply chain from the beginning. Our kit sources too many parts from too many different manufacturers, which resulted in an inventory nightmare. 90% of delays were because some part was missing, and not due to a manpower shortage. All too often, in a panic, we would rush-ship parts at a high cost, so that we could reach a deadline we’d decide upon. 

  • Particularly when ordering bulk products from China, the wait time can be many weeks. Something as small as missing spade terminals can bring the assembly line to a screeching halt.  
  • Sourcing parts from one place at a higher cost (e.g. Digi-Key) rather than sourcing those parts from two dozen different eBay sellers pays off in time and headaches saved.
  • Take advantage of value-added services. They are usually worth it. For instance, we could have bought pre-cut, pre-spooled lengths of primary wire, optical wire and GDT wire had we chosen the right suppliers. Digi-Key offers microcontroller programming which we may use in the future, but in the past year we flashed all the chips in-house using a custom board. It’s also possible to buy some parts in bags instead of reels, which saves hours of cutting them apart. Small savings in time add up.

The procedure for ordering parts from a manufacturer when there’s no way to order online took some getting used to. It usually goes something like this:

  • Step 1: You send a Request for Quotation (RFQ), which includes drawings, descriptions, material information, details about the manufacturing process, target price (optional), payment terms, etc.
  • Step 2: Receive back a quote from the manufacturer.
  • Step 3: Send a Purchase Order (PO) which references the quote number. Include any Terms and Conditions here, such as expected delivery date, consequences of significant delays, or whose responsibility shipping costs and potential shipping damage will be; A Google search for “purchase order with terms and conditions” will show you some good samples, but it’s good to have these looked over by a lawyer.
  • Step 4: Receive a sample, approve it or request changes.  
  • Step 5: After the items are made, receive them with a packing slip and an invoice. A packing slip is in the box, which references the PO number. The invoice is sometimes mailed separately, or just emailed. Be sure to check each shipment as you receive it, so that you can catch any damaged or missing items immediately.  
  • Step 6: Pay the invoice via check or bank transfer. Checks are slow to clear and slow to mail, but bank transfers have a hefty fee.

Resources for sourcing parts: 

  • Ebay.com: You’ve probably all used it; you can find some small things very cheaply in huge quantities on eBay if you use search terms wisely. Ebay is mostly targeted towards consumers, but you can find some bulk items. 
  • Alibaba.com: Dirt cheap wholesalers from around the world, mostly from China. If you post an RFQ, be prepared to be inundated with emails from ten dozen “Lucy Chang”s and “Amy Hu”s. The sales reps suspiciously have nearly exclusively women’s names and stock photos of attractive young women... perhaps they're trying to appeal to a demographic of middle-aged men. Alibaba is intended for large-scale wholesale and typically has minimum orders in the hundreds. 
  • Aliexpress.com: Like eBay, but it’s more intended for B2B sales, as many items are only available in multiples, though not quite the huge scale of Alibaba. It has a friendlier UI than Alibaba as well. 
  • MFG.com. In the words of a friend of ours, “MFG.com is like the OkCupid of matching you with shady chinese machine shops.” Post an RFQ for a custom manufacturing job, get competing quotes from shops around the world! 

Sourcing Logistics:

  • For most custom jobs, leave at least a two month lead time for the process of tooling, manufacturing a sample, approving the sample, adjusting the tooling, and the first round of production.
  • Familiarize yourself with International Commerce Terms: http://en.wikipedia.org/wiki/Incoterms; payment/credit schemes such as: NET30 (buy on credit and pay after 30 days), paying for tooling upfront and for the parts as they arrive, 50% up front and 50% upon delivery (as Chinese suppliers often want), etc. 

Shipping: “Take my kidney, just don’t make me print shipping labels again!*”

(*actual quote) 

Printing mailing labels, managing special requests, processing address changes, notifying backers of tracking numbers, etc, takes longer than you think. There’s also a learning curve when choosing optimal mail services and filling out international customs forms, so delegate one person to the task. 

Decide on a carrier. USPS is 2-4 times cheaper than other carriers, particularly for international shipments, but you pay for it in reliability. USPS hands off mail to the recipient country’s local postal service, after which the package becomes untraceable. If the package is not successfully delivered, it's usually lost forever, but if you’re lucky it eventually returns to you. Good luck if you need support or to collect on a lost or damaged box, as USPS customer service is as good as nonexistent. UPS, DHL and FedEx are much better about service, but cost upwards of $300 per shipping box to some parts of the world. 

Get phone numbers from international backers!!! Kickstarter does not collect phone numbers automatically in its shipping information survey, but this is very important for international orders. We had a number of packages returned without the recipient even knowing that deliveries were attempted, because there was no way for the post office to get in touch with them if there was a problem with the address. 

Find a bulk mailing software that works for you. We’ve used USPS’s software Stamps.com which got the job done, but there are other services out there that might be better. Stamps.com is proprietary, slow, only allows one user at a time, and occasionally buggy.   

Screenshot of USPS mailing software, Stamps.com
Screenshot of USPS mailing software, Stamps.com

 Cost Estimation  

Per-unit cost: For a hardware project, your selling price needs to be at several multiples of the cost of components to you plus the price of shipping. When planning, consider the costs of the following: 

  • Ordering 20% extra stock to account for damage/loss/mishandling cost of packaging materials (boxes, bubble wrap, etc). 
  • Cost of labor for packaging 
  • Cost of labor for customer service tasks (replying to inquiries, updating shipping information, etc) 
  • Cost of labor for shipping
  • Cost of shipping to near & far locations

Initial start-up costs:

  • Cost of prototyping your product  
  • Cost of incorporating your company
  • Legal fees for consultations about your product & company (e.g. LLC vs C-Corp vs S-Corp?)
  • Legal fees for drafting an operating agreement between founders  
  • Legal fees for the drafting of Terms & Conditions and a Privacy Policy  

Monthly Overhead Costs:

  • Rent 
  • Utilities 
  • Employee payroll 
  • Accounting/payroll processing 
  • Taxes (businesses file quarterly, and you better not mess up your end-of-year W2s!) 
  • Insurance

Don't forget to value your own time. It’s easy to get swept up in the excitement of a project that takes off and neglect to calculate how many hours of your own time you pour into it. If it consumes your life, you need to make provisions for your own costs of living, whether funded by the project or from other sources, for the project to be able to continue at all.

Last but not least: was it worth it?

Ask us at 4AM, tape-gun in hand, and we might say no. Ask us when we’re well-rested and we’ll say: yes, absolutely! We brought six hundred baby Tesla coils into the world, something we didn’t imagine we could do. Don’t let our shortcomings scare you from trying something out. oneTesla has been an adventure that has taught us much more than we anticipated, and these are not things you can learn in a classroom. If we were to summarize:

  • Plan ahead
  • Expect the worst
  • Don’t give up!

Thanks again for all of your support and patience. Without each and every one of you, oneTesla wouldn’t have happened! 

 Happy coiling, everyone!

 -The oneTesla Team 

 P.S. Give us a Like at facebook.com/onetesla :)

1-Year Anniversary Mega-Update (Part 1 of 2)

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Dear backers,

It’s exactly a year after the end of our Kickstarter campaign. It's been a long year of hard work, many late nights of taping boxes, many panicked overnight-orders of missing parts, countless inquiries of when we’re going to ship rewards. At last, we’re done shipping kits! (The handful of domestic backers who are missing toroids right now will get a free upgrade to spun toroids; more at the end.)

This is the massive pile that went out today:

We haven’t posted for a long time because we wanted to update you with good news, but in all honesty the last many months have been a long, frustrating slog. We should have been better about writing updates, but every day all we would see is a never-ending list of unshipped addresses and no end in sight, and it was tough to write anything meaningful. Last January, we put the brakes on our Kickstarter campaign a quarter of the way through because we were concerned that we couldn’t handle the demand; looking back, we wish we had taken on even fewer initial reward commitments. It has taken an enormous amount of work to set up a production facility, and there are many things that have taken time to learn from experience. 

We want this post to be something that we wish we had read before we had started. We want to share our struggles and experiences that we can better understand in hindsight. We hope that this is not only valuable to our backers who believed in us and supported our project a year ago, but also to other entrepreneurs and hobbyists wanting to share their passions but not knowing exactly how. 

Pre-campaign planning 

  • Have a serious contingency plan for various sales volumes. When we were starting out, we didn’t believe that demand for our kits would be so high during our Kickstarter campaign. Tesla coils are a niche product for experienced engineers, why should they be so popular?! We really thought we would be lucky to barely meet our goal in four weeks, so we weren’t prepared to take leave from school for a semester, which would have helped. While we always took our responsibilities seriously, it took a while for it to sink in that we really needed to consider it more than a side project. 
  • Be as well-prepared as possible before the start of your campaign. This is something we feel we did well with regards to product design, as our Tesla coil prototype was completely finished, tested and documented in advance. We also had quotes for all components and a few options for where we could source them. But our fulfillment plan had much room for improvement. We had designed projects before, but we never managed a supply chain, dealt with bulk shipments, or packed boxes before, so we had no idea what would be involved. For a month, we received thousands of dollars of shipments at Heidi’s dorm, which slowly filled half her room, while frantically searching for a better space. We did not keep good records of what we ordered in which quantities, which became problematic later when we started running out of parts at different times. We could go on. 
  • Decide what you actually want to spend your time on. Do you want to design hardware or run a fulfillment company? It might be more efficient to contract out work early than to try to do it all yourself. We wish we had sent out the kit packaging early on to avoid needing to manage the day to day activities of a packaging army for many months. However, it was a challenge to outsource anything while we had so much trouble with performing the kitting well ourselves in the first place -- reasons will be described further on. 

Workspace and Workforce

  • Be realistic about the size of the workspace you need, and get in there fast! At the beginning of the Kickstarter campaign, we figured that between MITERS and our dorm rooms, we’d have enough space to package the hundred rewards we expected. Well, that plan didn’t last long. We are fortunate to have had Artisan’s Asylum close to us. “The Asylum,” as we call it, is a huge makerspace with a long waiting list for space, but we knew someone who was leaving and were lucky to take his spot in the “robotics co-working area.” The idea was that the area was a flex space, where projects could expand when necessary and contract back down when finished. Unfortunately, a wide open area tends to fill with clutter, particularly from the renters who don’t show up often, so the co-working utopia never really worked out. We were confined to a 10ft x 10ft square space in the crowded warehouse, in which we put some shelving, chairs and and a table. Pallets of bubble wrap and some large crates of our parts were put on some borrowed racks nearby. Because the space was extremely small, we would have to work in shifts with no more than two people there at a time. 
  • Be smart about how you manage people. While everybody who worked for us has been wonderful, we should not have segmented our workforce as much as we did. Then again, in the tight space we were in, there was no other choice. Since only two people would fit in our tiny workshop at Artisan’s Asylum at a time, one shift would pack small parts, the next would make boxes, the next would print shipping labels and put them on the boxes, etc. The shifts accommodated people’s varying schedules, and no one would have to spend more than five hours at a time in the intolerable workspace right next to a metalworking shop with an air compressor running half the time. But no matter what we tried, the shifts didn’t communicate well, and they didn’t always work productively when there was nobody there to manage what they were doing or answer questions like “where the heck did the power adapters go?” It was very frustrating to see manpower wasted because we could not be there constantly to supervise. 
  • The search for commercial real estate is long and painful. We kept thinking that if we just pushed harder and pulled longer days, we’d be finished with Kickstarter soon. The Asylum was cheap and conveniently located, and included wood and metal shops that we thought might be useful. But at the beginning of the fall, we knew we needed to go somewhere else. We started to undergo the very time-consuming process of visiting potential new spaces and negotiating with realtors, without a car and during the middle of the semester. It was a massive headache. At last we signed a lease and moved into a 600 square foot space in the building of a family-owned knife & culinary supply company last month, but this is still not our final workshop. Next week we’re moving into yet another temporary space while the one we’re in is rented to someone else, and in another month or two we will move into another portion of the building that’s being subdivided. 

Part 2: Manufacturing and sourcing, coming soon!

Notes: 

To the Round 4 backers who are missing a toroid, if you don’t hear from us tomorrow, you are getting a free upgrade to a spun toroid with a beautiful surface finish! The shop that does the stamping doubled their price for an already-expensive part that they deliver very slowly, so we bit the bullet and paid for tooling at a spinning house. ETA is 2-3 weeks. 

To anyone with questions about tuning: if your secondary measures under 228 ohms, you should use a 5-turn primary. Otherwise, keep the 6-turn primary as described in the manual. After much scratching our heads, we learned that the manufacturer had switched from signal build wire to heavy build, which has thicker enamel and therefore fewer turns in the same length of wire.

Toroids at last! (and other news, too)

Dear backers,

We have some updates for you! Let's start with the good news: Our toroid manufacturer has finally pulled it off! We got three beautiful samples on Wednesday, and we gave him the go-ahead for mass production.

What have we learned from this ordeal? First of all, it’s critical that your manufacturer have experience in exactly the process that you need. Our manufacturer is a reputable machinist, but did not have specific experience in metal stamping. What he thought was an easy job gave him a seven-month headache. We’re surprised that he pulled through, and didn’t give up and return our deposit. We had even gotten quotes from other manufacturers, prepared to start over right away if we got our money back.

There’s some bad news as well, which is the reason all the rewards haven’t been shipped yet. The manufacturer producing the laser cut chassis had a fire in his laser cutter, which is putting him out of commission for a month. This was the manufacturer that, according to our last update, we previously could not get in touch with. Strangely, despite being impossible to contact, he kept sending us 25-50 units per week. This rate is far too slow for our needs, but at least he didn’t just take our money and run. We were not very explicit about deadlines in our initial correspondence with him, so despite all our frustration with him, he was technically not violating any contract. When searching for suppliers many months ago, we had also gotten quotes and samples from a Chinese firm. We decided to quickly reach out to them so that we would minimize the delay in shipments. Our design had changed slightly since the spring, and he insisted on our approval of another round of samples before he started production of several hundred chassis. Those have arrived this week, so we’re working around the clock to fill the boxes we’ve got ready with the missing chassis and ship them out. Despite having paid for everything with the first manufacturer, we will probably have to commission several hundred more from overseas so that we don’t run into another roadblock with the last round of Kickstarter orders. We didn’t think it would be so complicated to find a reliable firm to do laser cutting of 1/8" acrylic sheet, but in truth you never know when you’ll run into a roadblock.

What have we learned from this?

  • Ensure that your manufacturer is capable of handling your order volume. We got an excellent price and communicated easily with our first manufacturer to begin with, but now we’re under the impression that he only has a single small laser cutter. If we were to start again, we would demand more information about the production facility, such as pictures or an in-person visit.
  • It would also have been nice to have found someone local to do the production, so that when he stopped replying to our emails and phone calls we could have knocked on his office door to ask what’s going on.
  • You need to be explicit about deadlines with manufacturers, and set penalties for not meeting them.

Had it not been for the missing chassis, we would have already shipped all of your rewards (minus toroids, of course). The toroids will be boxed and sent out as they arrive, which should be very soon, now that mass-production has begun. It will be a very busy next few weeks!

Happy coiling,

The oneTesla team