Note: This is a crosspost of a Cynthion update on Crowd Supply: https://www.crowdsupply.com/great-scott-gadgets/cynthion/updates/cynthion-shipping-soon

The first few Cynthions have come off of the manufacturing line! Once the first full batch of Cynthions is completed we will send them to Mouser who will ship them to you, our backers. Shipping will happen soon, so please make sure your address on Crowd Supply is up-to-date. If you need assistance with an address change please contact Crowd Supply. We will post another update once the first orders leave the Mouser warehouse. Until then, please enjoy these photos from our contract manufacturer.

Batch of Cynthions before last USB component was soldered on.

Enclosed Cynthion ready to ship

Batch of enclosed Cynthions ready to ship

The December 2023 recipient for the Great Scott Gadgets Free Stuff Program is a STEM Camp where students will have the opportunity to use the requested HackRF One to do a Quantum Physics experiment with laser light and modulated RF. We are excited to see how the experiment goes and to see pictures from the camp!

The November 2023 recipient for the Great Scott Gadgets Free Stuff Program is Ryan. Ryan works as a wireless systems administrator for a public school. He coaches robotics and programming teams after school. Ryan has asked for a HackRF One to show the students in his clubs how to interact with the wirelss devices around them and to inspire them to explore RF as future career options.

Note: This is a crosspost of a Cynthion update on Crowd Supply: https://www.crowdsupply.com/great-scott-gadgets/cynthion/updates/cynthion-manufacturing-progress

Cynthion update time!

Final samples have been manufactured, some of them have been sent for RoHS testing (and each of them has passed), and manufacturing is under way. Everything’s going great so far, and we’re on track for June shipping!

Here is your first glimpse of finished Cynthions in their enclosures and in the boxes we will be shipping them in.

The significance of RoHS testing is that Cynthion had to pass that test in order for us to earn our CE marking, which allows us to sell Cynthion in the EU. RoHS stands for “Restriction of Hazardous Substances in Electrical and Electronic Equipment” and this directive requires that electronic and electrical equipment does not exceed certain thresholds for lead, cadmium, mercury, and other hazardous substances. RoHS testing is completed by a third-party lab and the lab we chose used “destructive testing methods” which meant that we had to send a few completed Cynthions, including enclosure and packaging, for them to destroy.

Note: This is a crosspost of a Cynthion update on Crowd Supply: https://www.crowdsupply.com/great-scott-gadgets/cynthion/updates/cynthion-has-passed-emc-and-tycho-has-shipped-to-our-manufacturer

The title says it all! Cynthion has passed EMC testing which means it is ready for manufacturing and Tycho, our Cynthion-testing quality assurance rig, has been shipped to our manufacturer. Our next steps are to work closely with our manufacturer to create final product samples, ensure the QA process is achieving the results we expect at factory level, and receive the final product samples and test them in-house here at Great Scott Gadgets. We’ll have more for you soon!

Note: This is a crosspost of a Cynthion update on Crowd Supply: https://www.crowdsupply.com/great-scott-gadgets/cynthion/updates/cynthion-design-work-completed

We are happy to say that early this month we completed the design work for Cynthion! This milestone is the culmination of yet another three months’ worth of work. Since our October update we have:

• revisited the EMC testing lab for another round of pre-compliance testing,

• used the EMC testing results to improve signal integrity on Cynthion and produce another hardware revision,

• ordered another revision of the Cynthion enclosure prototypes,

• designed and ordered prototypes of the Cynthion packaging,

• produced another Cynthion hardware revision to fix minor issues,

• rearranged the Cynthion schematic,

• updated documentation in Cynthion-related repositories,

• ordered a production sample of Cynthion,

• worked on the Cynthion manufacturing test jig and test scripts,

• worked on apollo, luna, saturn-v, packetry, and Facedancer (all of which are used in conjunction with Cynthion or as part of manufacturing testing), and

• scheduled another visit to the EMC testing lab for this week and taken Cynthion in for final evaluation.

Since we’ve only recently reached the milestone of finishing the design work, it means Cynthion delivery will be delayed until June to allow time for manufacturing and shipping. Here is what the current timeline to delivery looks like:

January

Since the completion of Cynthion’s design, we have pivoted to finishing up the hardware test jig (which we have named Tycho) that we will send to our manufacturer so they can test each Cynthion as it comes off the production line. Designing this test jig has required multiple revisions that have changed slightly with each revision of Cynthion. Since Cynthion is so unique in its design we have even had to develop custom cables for Tycho. This is a story we are looking forward to telling you all about once the Tycho team has completed their work.

February

Our manufacturer is based in China and they will be unavailable almost all of February due to Chinese New Year celebrations. We will spend this month continuing to work on Tycho, documentation for Cynthion and related projects, and improving software, firmware, and gateware. By the end of this month we will ship Tycho to our manufacturers.

March

Cynthion will be in manufacturing for month one of two. In this month our manufacturers will produce the Cynthion PCBs, enclosures, and packaging. PCB production is expected to take about 2-3 weeks. As soon as the PCBs are produced, we will get a few production samples from the manufacturer for extra verification and testing by our team at Great Scott Gadgets. During this month we at Great Scott Gadgets will continue working on all of the Cynthion-related repositories and documentation.

April

Cynthion will be in manufacturing for month two of two. In this month Cynthions will be assembled, tested, and packaged by our manufacturer. Like March, we at Great Scott Gadgets will continue working on all of the Cynthion-related repositories and documentation. Additionally we will provide technical support to the manufacturing test team.

May

Cynthions will be on their way from our manufacturer in China to Crowd Supply’s fulfillment partner (Mouser) in the United States. At minimum this is expected to take two weeks, but we have scheduled an entire month for shipping as there can be lengthy customs delays when shipping internationally. This means that if there are no customs delays you may get your Cynthion sooner! Wish us luck.

June

The moment you’ve been waiting for! Cynthions will be shipped to you! If you have moved, you’ll want to make sure that you’ve updated your address on Crowd Supply before this point. Don’t worry, we will post an update before June reminding you to update your address.

The October recipient for the Great Scott Gadgets Free Stuff Program is the Illinois Space Society, which is a student-run non-profit 501(c)3 aerospace organization at the University of Illinois Urbana-Champaign campus. The Illinois Space Society hosts a variety of technical projects and educational outreach programs. One of their largest technical projects, Spaceshot, is aiming to be one of the first collegiate teams to build and launch a two stage rocket to 100km, also known as the Kármán line, the beginning of space.

Over the past two years they’ve been working on creating flight computers that can accurately conduct state estimation at extreme high altitude. The group says “GPS is undoubtedly the most accurate form of positioning we can utilize, but most consumer grade modules are not rated for those extreme altitudes or speeds. Our hope is to use the HackRF One as a GPS simulator to help test our modules in an easily reproducible manner without the need for an expensive test flight. With that said, a HackRF One would also allow us to expand beyond the range of our RTL-SDR to help debug our ESP32-S3 wifi modules and our upcoming wireless 5GHz video systems.” The Illinois Space Society also plans to use the HackRF One we send them to help kickoff their radio club. We look forward to seeing what projects the Illinois Space Society does from here!

We hope everyone has a great holiday season! If you are trying to get in touch with the Great Scott Gadgets team please know tomorrow (December 22nd) will be our last day in the office until the 2024 calendar year! This means that we will not be available through email, on Discord, or via GitHub. See you all in January!

The September recipient for the Great Scott Gadgets Free Stuff Program is Erik. Erik is an Ojibwe filmmaker and artist. He has only had his amateur radio license for a short while but he is already assisting in running community demonstrations on how amateur radio can help in emergency situations. We are sending Erik a HackRF One so he can build a mobile training station and take his emergency preparedness demonstrations on the road to Native communities. As an avid camper and road tripper, Erik is also excited to eventually take his demonstrations into wilderness settings and rural communities. We look forward to seeing Erik’s mobile training station and getting updates on where he has taken it.

Note: This is a crosspost of a Cynthion update on Crowd Supply: https://www.crowdsupply.com/great-scott-gadgets/cynthion/updates/improvements-to-cynthion-hardware

Since our last hardware design update in April, we have been hard at work refining the Cynthion design in preparation for production. Believe it or not, we’ve completed and tested six design revisions since r0.6 described in April!

In r0.7 we increased the maximum pass-through current by selecting FETs with lower resistance and by improving heat dissipation of the PCB layout. We added filters to the buttons, reducing the need for debouncing in firmware and gateware. We added a zero ohm series resistor to the oscillator so that it could be replaced easily with a higher resistance if indicated by electromagnetic compatibility (EMC) testing. We also updated several component selections and added or removed various pull-up and pull-down resistors, ensuring that we follow recommendations for the FPGA and microcontroller.

After testing these improvements, we decided that the design was ready for pre-production. We updated a few component selections, refined some nuances of the PCB layout, and bumped the hardware version number from r0.7 to r1.0.0.

Hardware Semantic Versioning

At this time we adopted an internal standard for hardware semantic versioning. It can be difficult to know how to version hardware designs, so we chose to make our decision process easier by establishing a set of rules adapted from the popular semantic versioning standard for software. While the software semantic versioning standard is focused on the software’s Application Programming Interface (API), our standard for hardware focuses on the hardware/software interface.

As an example, a change to the PCB layout that has no affect on software would warrant a bump from 1.0.0 to 1.0.1, but swapping pin assignments on a microcontroller (necessitating different firmware behavior) would require the version number to be bumped from 1.0.0 to 1.1.0. While software version numbers are often prefixed with “v”, we use “r” for hardware, making it easier to tell if we are referring to a software version or hardware version.

Although r1.0.0 differed very little from r0.7, we bumped the major version number to indicate that it was the first version handed off for volume production. It later turned out that further revisions were required, but r1.0.0 was the first version that conceivably could have ended up in your hands.

The Component Shortage Strikes Again

As mentioned in Cynthion Delivery Timeline Update, we soon learned that the power monitoring component used in r0.6 through r1.0.0 was no longer available. While many thousands were available just three weeks earlier, they all had vanished in the short time between prototyping r0.7 and purchasing components for production!

Fortunately, we were able to find just enough of an alternative component, so we snatched it up and designed and tested another revision, r1.1.0, using the new part. Because the new part is the same IC in a different package, nothing needed to change in r1.1.0 except for the PCB layout and some pin assignments.

Around this time, we received new enclosure samples, updated for the larger PCB size introduced in r0.6. The samples were great, but we noticed that they made the buttons feel inconsistent. It was very difficult to center the PCB in the enclosure such that the button plungers all extended the same distance. A certain amount of play in the placement of the PCB within the enclosure is unavoidable, but for some reason it seemed to be nearly impossible to center the PCB perfectly.

Upon further investigation, the problem turned out to be with the PCB design, not the enclosure. When I had added a new button in r0.6, I accidentally placed it 0.1 mm closer to the PCB edge than the other two buttons. It wasn’t noticeable at first, but, once the board was placed in an enclosure, it was possible to feel the difference! We corrected this tiny discrepancy in r1.1.1.

Electromagnetic Compatibility Challenges

After our first round of EMC pre-compliance testing we hoped that we would be able to pass a second round with some software modifications and minor hardware updates (such as increasing the value of the oscillator series resistor). While some of these measures were effective, they weren’t enough to pass the emissions test. After our second test we determined that another hardware design revision was required to reduce electromagnetic emissions.

In r1.2.0 we significantly improved power supply connectivity and decoupling for the FPGA which seemed to be the principal remaining source of emissions. Most of these changes were enabled by updating the PCB from four layers to six. Additionally we added series resistors to the ULPI bus that connects each USB PHY to the FPGA. We suspected that these resistors may be unnecessary (except perhaps the ones on the ULPI clock signals), but it is much easier to swap in different resistances than it was before we added those resistor array footprints.

Our next pre-compliance test clearly indicated that we had successfully quashed emissions from the FPGA, but the we still had a borderline result. One of our configurations passed the test but with very little margin. We felt that we needed to reduce emissions further to ensure success in the formal test.

With the FPGA noise out of the way, it had become possible to detect emissions from the USB PHYs. After some experimentation, we determined that these emissions could be reduced with further modifications to the PCB design and enclosure.

We addressed PHY noise in r1.3.0 by improving shielding and PHY power supply decoupling and by installing common-mode chokes on the USB data signals. Additionally we made a change to FPGA control that makes it easier to recover a Cynthion bricked by bad gateware, and we fixed a power supply start-up bug that was introduced in r1.2.0.

I’m pleased to report that r1.3.0 passed EMC pre-compliance testing! There are some small bugs that need to be corrected in one more hardware revision, but we are now confident that Cynthion will pass the formal EMC test.

Viewing the Design

Most of the changes since r0.6 are unlikely to ever be noticed by a Cynthion user, but they all enhance the quality of the product in some way. The most significant functional change is that pass-through power now supports up to 3 A of current.

Design documents and fabrication outputs for each of these hardware revisions have been released in the new cynthion-hardware repository. Previously the design was included in the LUNA repository which now contains only the LUNA gateware library.