Great Scott Gadgets

open source tools for innovative people


Free Stuff - October 2022

The October recipient for the Great Scott Gadgets Free Stuff Program is M0nkeyDrag0n! M0nkeyDrag0n has requested a GreatFET One in order to explore a potential bug he found in Windows. We love supporting researchers and look forward to hearing about what M0nkeyDrag0n finds.


Free Stuff - September 2022

The September recipient for the Great Scott Gadgets Free Stuff Program is Brett! Brett volunteers at the Wasatch 100 in Utah. The Wasatch 100 is a 100 mile endurance run through the Wasatch National Forest. Brett is planning to use the HackRF One we are sending him to streamline the race aid station communications. We look forward to seeing the solution he comes up with.


Introducing Opera Cake

Starting this week, we are shipping Opera Cake, our multi-use antenna-switching add-on for HackRF One!

Opera Cake mounted on bareboard HackRF One

This add-on board has two primary ports, each connected to any of eight secondary ports, and it is optimized for use as a pair of 1x4 switches or as a single 1x8 switch.

As a 1x8 switch, Opera Cake can connect your HackRF to a variety of antennas at once, such as a long wire antenna for HF bands, a discone for VHF and UHF, a dipole for 2.4 GHz, and a dish for a satellite band. Once connected to your Opera Cake you can switch between all of your antennas in software instead of making physical hardware swaps.

Opera Cake as 1x8 switch

When set up as a pair of 1x4 switches you could use Opera Cake as a switched filter bank. To do this, connect port A1 to B1, A2 to B2, A3 to B3, and A4 to B4 through physical SMA filters and cables of your choosing. This setup allows you to change your transmit or receive to be through the filter of your choosing without having to reconnect hardware every time you would like to use a different filter.

Picture of Opera Cake as a switched filter bank

You can control Opera Cake for HackRF One manually with our command-line software hackrf_operacake, or you can configure HackRF One’s firmware to automatically switch Opera Cake ports based on frequency or time. Automated antenna switching and hackrf_operacake are both available in the latest HackRF One release. You can learn more about Opera Cake’s modes of operation in our HackRF documentation.

If you are looking to pick up an Opera Cake of your own, please check our website for the list of Great Scott Gadgets Opera Cake resellers. We hope you enjoy Opera Cake and stop by our Discord, or tag us on Twitter or Instagram, to show us your Opera Cake projects!


Pseudo-Doppler Redux, ShmooCon 2018

Back in 2018 Michael Ossmann teamed up with Schuyler St. Leger at ShmooCon to present “Pseudo-Doppler Redux”; a talk about taking a modern approach to the implementation of pseudo-doppler direction finding (DF) with Software Defined Radio (SDR). This presentation demonstrates what pseudo-doppler direction finding is and gives an example of Opera Cake usage.

We hope you enjoy watching the presentation!


Free Stuff - August 2022

The August recipient for the Great Scott Gadgets Free Stuff Program is Trevor! Trevor is working on a project called Hack365 where he is attempting to blog about one hack (or make or break or fix or learn) each day until next DEF CON. We are excited by how enthusiastic Trevor is about documentation, sharing his experiences with the community, and learning new things. One of the projects Trevor plans to take on is learning about his ceiling fan’s RF receiver, which is an excellent place to start when you are learning about RF. Trevor plans to share his progress with the DEF CON group DC612 as he progresses. We wish Trevor happy hacking and hope he continues to share what he learns so all of the community can benefit!



Free Stuff - July 2022

The July recipient for the Great Scott Gadgets Free Stuff Program is Manoj Kumar Mondal from India! Manoj requested a HackRF so he could take some security courses at his university; having a HackRF is a pre-requisite for the course. We look forward to hearing from Manoj as he progresses through the course!


Free Stuff - June 2022

The June recipient for the Great Scott Gadgets Free Stuff Program is Kyle from SkullSpace. SkullSpace is a hackerspace located in Winnipeg, Manitoba, Canada. Kyle plans to put together a group of SDR and wireless enthusiasts. This group will put on classes, host labs, and lead projects that help the community learn more about SDR and wireless. If you are ever in Winnipeg on a Tuesday evening we hope you take advantage of SkullSpace’s open night and check out their hackerspace!


FPGA Substitution on LUNA

This is a cross post from our LUNA project page on Crowd Supply.

Global supply chain issues continue to be difficult to traverse, but once in a while we do get a little bit lucky! In a previous update [1] we mentioned that Lattice had pushed out the lead time on our FPGAs for LUNA from 30 weeks to 60 weeks. Well, the expected delivery date for those FPGAs got pushed out again. Thankfully, we were able to purchase another ECP5 part for the first batch of LUNAs from an authorized Lattice distributor in a 381-ball package rather than a 256-ball package. We already have the 381-ball FPGAs in hand, so we don’t have to worry about those lead times changing again. We are still waiting on other components though, so with this FPGA substitution our estimated shipping date for LUNA will still be December 2022.

Changes to LUNA

Both FPGAs are from the same manufacturer and are part of the same line. The firmware and software we are creating will work the same regardless of which of the FPGAs is present on a given LUNA board. The primary difference impacting LUNA is that the substitute FPGA is slightly bigger than the original FPGA we had picked out. The original FPGA was 14x14 mm and the substitute FPGA is 17x17 mm. To accommodate this change in size we expect to increase the board area of LUNA to 51x51 mm instead of its original 48x48 mm.

LUNA with size increase

This change adds 297 millimetres squared of available space. 93 millimetres squared of the extra space will be taken up by the bigger FPGA which leaves 204 millimeteres squared to use. The Great Scott Gadgets team has not yet settled on what we will be doing with the extra space but we will update you all as soon as we finalize our decisions. If you would like to make requests for or share your thoughts on what to use this space for, please come discuss in our Discord server.

[1] https://www.crowdsupply.com/great-scott-gadgets/luna/updates/luna-delayed


Free Stuff - May 2022

The May recipient for the Great Scott Gadgets Free Stuff Program is C.J. who is a Broadway tour sound engineer that works backstage with wireless RF microphones. Every week the tour moves to a new location and C.J. has to re-coordinate wireless frequencies for the show. He’s hoping to use the HackRF we are sending him to improve his RF monitoring and create more precise RF layouts for the travelling shows.


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