I grew up golfing and I love to make things, so I thought it’d be pretty funny and ridiculous if I made a voice activated golf bag that shoots out your clubs. Like a robotic caddy of sorts.
The video explains some parts of how I built it and shows it off more (I even got to bring it to England to show Rick Shiels, a popular golf YouTuber), but I’ll highlight a few other key points.
- Getting this thing to rotate and finding the right motor took me a lot of time. A bunch of stepper motors I tried initially were too weak and would “skip”. I did some MOI calculations and talked with some engineers (this math was new to me) and I eventually found a motor that was just barely strong enough. I threw a 10:1 gearbox on it to solidify the torque requirements and called it a day.
- The motor didn’t rotate very accurately in terms of degrees. So trying to rotate 30 degrees would actually rotate 30 degrees +- 4 degrees. Over time, there was a lot of drift and rotating a certain number of degrees became completely inaccurate. I came up with a solution where a microswitch was clicked every time a club went by. That way, the motor rotated until a certain number of clicks happened instead of X number of degrees. The video breaks this solution down more.
- The voice assistant software is Rhasspy, an open source offline voice assistant. It had to be offline since I wouldn’t have internet connection on the course. That runs on a raspberry pi and also has the microphone and speaker hooked up to it.
- Originally I was going to use a fancy microphone that has lights and that took up all the pins on the pi, so I planned to use I2C to send commands to an Arduino to control the motor (and solenoid valves which controlled the airflow to the air cylinders that actually shot out the club). I set all that up then changed the microphone at the last minute. If I had more time, I would have removed I2C and just used the Pi. Since I didn’t have time, the current implementation is a Pi and Arduino talking over I2C.
- The video shows how I 3D printed some parts to make the clubs stay aligned in one direction so they don’t smash into each other when they eject from the bag. Just wanted to call out I’m really proud of this solution :)
I can't imagine placing the push handle at the gazing-down-the-barrel end of this contraption without constant background anxiety about losing an eye or a few teeth.
Maybe it's an intentionally motivating reminder to get to work on the autonomous caddy feature?
I clicked through fully expecting this to be a stuff made here video, that channel is definitely a pro click.
That said, I subscribed to Nick's channel just from watching this video, very fun project and good video skills. Glad he submitted it to HN, YouTube recommendations have been kinda crap in the last year and always happy to run across a new channel with interesting projects.
Thanks so much :) Really glad you liked it. I love making these videos. They just take so long to make. I love these final "showcase" type videos that are really cleanly edited but I'm also considering mixing in "here's how it's going right now" and releasing those videos more frequently to show that process before I release the final video (that is edited like this one).
Worth pointing out that someone engineered a replica of the caddyshack bag, including club launcher, 5 liter beer keg with tap, working radio, telephone:
Confession: I’ve never seen Caddyshack. But after everyone telling me about my bags reference to the movie, I watched the clip where the golf bag shoots out the club haha and I can see the crazy coincidence
If you ever want a motor that can do any high torque job for <$5 go to an autowreckers and try a windscreen wiper motor. They are amazing.
You should already have in mind the performance of these super cheap motors. Think of the torque of a the top of the wiper encountering newly fallen snow/torrential rain/leaves that they commonly have to overcome. They internally have metal gears, are high speed and are designed to be maintenance free.
I've used them for automatic farm gate openers, wire spoolers (spinning out 2 ton spools of fencing wire with no further gearing, just a good flat bearing holding it) and a bunch of other contraptions over the years.
Bravo, I've got so much time for this kind of technical tomfoolery!
A few feature requests that I'm 100% not prepared to pay for:
* Commentary mode upon hitting the ball: Offers words of encouragement in inspiration mode or lots of expletives in troll mode
* Countdown beeps so you don't need to look to see when a projectile is coming at you
* Primitive turn by turn directions to get the projectile receiver in the optimum landing zone. E.g "Back a bit", "to the side a bit", "tuts back a bit more"
Wow can you make it look like some kind of R2-D2 form factor and make it respond with beeps? Then we can have a legit reason to own a droid. It’s the future!
What was used for the calculations for the voice assistant? I'm sure a lot of that is pretty well defined out there, but I'm not into golf so I wasn't sure.
Also was wondering about the "ball dispenser"- were you feeding a ball back into a tube for that, or is there a mechanism for loading the next one that wasn't explicitly shown, sort of like a pinball machine?
Basically +- 4 yards if it's SLIGHTLY uphill/downhill or SOME wind in either direction. If you were STEEPLY uphill/downhill or there was STRONG wind, +- 12 yards. This was just trial and error on the golf course honing it in. Would be cool to have some sensors to make that even more specific.
There were 2 tubes for the ball, so they would need to be reloaded. But my friend Jason did have a design for how I could have 12-15 balls that would automatically feed in. Just didn't have time to implement it :(
Pitching wedges were originally 48, now they're in the 46-47 range.
Tour players have very different lofts depending on type of iron and ball flight. For normal players though, companies like to deloft the irons to 1) make them go further so if you're comparing a 7 iron, you want to buy the one that goes further even if you don't know the reason is because the loft is different and 2) because the cavity backed design and soft material makes the ball fly higher than a blade, which can cause problems. Like the wedge example, a soft cavity back can go super high so they have to knock it down a few degrees.
The video explains some parts of how I built it and shows it off more (I even got to bring it to England to show Rick Shiels, a popular golf YouTuber), but I’ll highlight a few other key points.
- Getting this thing to rotate and finding the right motor took me a lot of time. A bunch of stepper motors I tried initially were too weak and would “skip”. I did some MOI calculations and talked with some engineers (this math was new to me) and I eventually found a motor that was just barely strong enough. I threw a 10:1 gearbox on it to solidify the torque requirements and called it a day.
- The motor didn’t rotate very accurately in terms of degrees. So trying to rotate 30 degrees would actually rotate 30 degrees +- 4 degrees. Over time, there was a lot of drift and rotating a certain number of degrees became completely inaccurate. I came up with a solution where a microswitch was clicked every time a club went by. That way, the motor rotated until a certain number of clicks happened instead of X number of degrees. The video breaks this solution down more.
- The voice assistant software is Rhasspy, an open source offline voice assistant. It had to be offline since I wouldn’t have internet connection on the course. That runs on a raspberry pi and also has the microphone and speaker hooked up to it.
- Originally I was going to use a fancy microphone that has lights and that took up all the pins on the pi, so I planned to use I2C to send commands to an Arduino to control the motor (and solenoid valves which controlled the airflow to the air cylinders that actually shot out the club). I set all that up then changed the microphone at the last minute. If I had more time, I would have removed I2C and just used the Pi. Since I didn’t have time, the current implementation is a Pi and Arduino talking over I2C.
- The video shows how I 3D printed some parts to make the clubs stay aligned in one direction so they don’t smash into each other when they eject from the bag. Just wanted to call out I’m really proud of this solution :)