The Briffidi SW1 allows you to quickly and accurately measure the swingweight of tennis, squash, racquetball, and badminton racquets. Available pickleball adapters (5 cm or 0 cm) allow measurement of paddles. An available twistweight adapter allows high precision (never before available) measurement of tennis racquet twistweight.
Highly Accurate and Precise
The SW1 is spring-driven and oscillates about a vertical axis to measure swingweight independent of mass and balance measurements. The companion apps (available free in the Apple App Store and Google Play) use the gyroscope sensor in your phone to measure with high precision. A retractable rod labeled with two individualized calibration values is included. While the SW1 costs much less, accuracy is as good or better than other swingweight machines.
Easy to Use
After initial setup, place your phone into the holder on either side of the SW1 cradle, rotate the front of the cradle to the left, tap the Measure button, and release. The swingweight measurement will display in seconds. The SW1 is small, requires no external power, is easy to store, and is easy to transport.
You Will Need
- An iPhone 7 or later – or – a phone running Android 8.1 or later with NFC capability and a physical gyroscope sensor. Android phones with non-standard form factors (flip, folding, etc.) may not fit securely in the SW1.
- Approximately 4,000 4.5 mm (.177 cal) steel BBs to add weight to the device. In the US, a package of 6,000 BBs is available from many retailers for ~$10 (i.e., Amazon, Walmart). The SW1 is much easier to package for damage-free shipping when unfilled and can be filled easily without tools.
The plastic components of the SW1 are 3D-printed in PETG, which is tough, durable, chemical-resistant, and heat-resistant.
Video Playlist: Briffidi SW1 Getting Started
Blog Post: Briffidi SW1 Linearity Testing
Video: AFFORDABLE SWING WEIGHT MACHINE WITH RAZOR SHARP ACCURACY! by Tennis Spin (featuring the SW1)
Video: Fix This Anytime You Buy a New Racquet by TennCom (featuring the SW1)
Questions & Answers
Q: BBs are difficult to get in my country. Can I use something else?
A: Yes. The BBs are used as ballast, so something similarly small and dense should work. The BBs required to fill an SW1 have a mass of ~1.4 kg. Sand or common pebbles will not work, as they’re much less dense than steel. A soft mesh diving weight, such as this one from Scuba Choice can be a good source of inexpensive ballast. I purchased the 3 lb. version to test, and it worked well. (Be sure to use handle the lead bits safely.) There was some space left inside the SW1, so the 4 lb. option would be even better.
Q: What happens if Briffidi ceases to exist?
A: The SW1 will still work. The app will continue to function; it does not contact a backend server. If the SW1 will no longer be supported, I will publish the app source code and the hardware design.
Q: How accurate is the calibration object?
A: I estimate that the marked calibration values are accurate to within ±0.6 kg·cm². The values are determined by swingweight measurement after calibration with a pair of reference rods. The length and mass of the reference rods are measured as part of each calibration.
Q: How often should I recalibrate the SW1?
A: If you move the SW1 to a new location, you should re-level and recalibrate it. I have marked the spot where I use mine, so I can place it back in the same spot and avoid re-leveling. You should recalibrate if the temperature changes significantly. For a typical racket, the measured swingweight increases by ~0.09 kg·cm² per °F (~0.16 kg·cm² per °C). Otherwise, it’s not necessary to re-calibrate except occasionally to verify that nothing has changed. When measuring racquets, I typically only take a quick measurement of the extended calibration rod to make sure it’s close.
Q: I broke something, can I get replacement parts?
A: Yes. I haven’t had to replace much, so I don’t have published spare parts. Please send a message to email@example.com, and I will work with you to get your SW1 back in service.