Introduction (aka. skippable rant)
Click me for a little bit of bitterness
Well, I’ve had enough. When I got into esk8, I risked my integrity with a remote that tried to kill me twice and a friend actually broke his arm using the exact same model. After that, I was happy with a Maytech for some years, but it started failing in RF congested areas. I don’t blame it, it served its purpose.
After that, I got a VX1 which at first worked perfectly. Love the ergonomics, was crazy reliable and cheap to boot. Then I started building boards for friends and family, and a whole slew of problems appeared:
- Puffing batteries (who the fuck seats the battery next to and sometimes on top of a screw?)
- Sketchy soldering on the potentiometer
- Random disconnections that required a reboot
And the straw that broke the camel’s back:
- Random “blips” where the remote wouldn’t disconnect, but the board would lose accel/brakes just enough to scare the fuck out of you. This happend to both mine and my GF’s board.
This is where I decided I would take matters into my own hands.
What this is
- A cheap, open, modular and reliable DIY remote with a focus on RF performance
- An alternative for similarly priced remotes that are often hit or miss
What this is NOT
- The absolute best remote there is
- An alternative to high performance premium products such as the Puck or the OSSR (mad respect for both projects, btw). I know lots of you will say “just buy a Puck, bro”, and you have a point…but I am the guy that broke his first deck and immediately went looking for veneer suppliers. I want options, I want openess, I want Flipsky to get fucked.
With this out of the way, I intend to keep this post updated as a living log of my progress. Let’s go!
Design considerations
- Unfancy. I use other devices for my telemetry, so no UART (even though could be easily added in the future) or OLED screens. PPM for the win.
- DIY friendly and modular. There are a ton of DIY remotes available (specially in the older forum), and most of them failed because in my opinion they weren’t easy to build. My hope is to have a comprehensive Github repo and do things at least 10% as well as @shaman does with his open projects!
- Stellar RF performance is a must. The whole idea for this project came after in the FPV drone space this project became super popular. It uses LoRa transcievers to achieve great range and link speeds, using a proprietary modulation that is specially robust against interference. It can also work on 433MHz/868MHz/2.4GHz bands depending on the specific module.
- A robust mechanical throttle is a must. The potentiometer in the VX1 is flaky and sensitive to dust (I didn’t have problems until used on my mountainboard, you should see the final color of the alcohol I used to clean it up one time).
First iteration: the pathfinder
Click me for a little bit of history
Choice of parts:
- Ebyte SX1280 E28-2G4M12S LoRa module: Inexpensive, SPI interface, 12dBm tx power, PCB antenna with the option of external one. Fun fact, I started this project a few weeks ago and just today realized that Flipsky has a VX1 PRO that uses exactly the same module. This pisses me off a lot because: a) they could have done better from the start and I wouldn’t be doing this, b) the thing is +60€ and probably uses the exact same crappy potentiometer and battery and c) it makes it look like I’m copying them. On the flip side, it somehow validates my choice of components (but I’m going to test the shit out of mine probably unlike them).
- Arduino nano/pro mini: Yeah, I know all the cool kids use 32bit processors now, but Arduinos are a lot more familiar to me (both sw and hw wise), easy to source, inexpensive and I don’t need the extra power anyway. Prototyping is going to go a lot faster like this. Also, there is an amazing library for the LoRa modules I intend to use.
- Linear hall sensors: At first cannibalized from a kit I found on amazon. Also had some neodymium magnets at hand.
My initial plan is to throw everything together and verify I can make it work. This manufacturing pathfinder must validate all the unknowns (for me). Specifically, I want to verify that I can make a reliable hall sensor throttle and that the RF performance is solid. With this in mind, this monstrosity was born:
First ideas, big ass hall sensor PCB that was ultimately removed. Here I was trying to deal in the throttle feel, and I actually like a lot the result of using a standard skate bearing. Simple, yet a LOT less play than the VX1.
Before the pro mini arrived, I had to use level shifters to make the LoRa module not blow up when connected to a 5V Arduino. Also the hall sensor looks like that because I moved it around a lot to find the optimal position. The case is only to grab it somewhat comfortably and without touching the electronics, but it is chonky. The final product will look a lot more like a VX1.
The receiver with the pro mini. A lot more palatable.
And the test:
We’re off the the races boys!!
Next steps
- Add battery, charging and power delivery circuits
- LEDs to at least get some basic feedback from the receiver (connection status, battery level?)
- Buttons (just power, modes?)
- Haptic feedback (love that on the VX1)
- Design a proper PCB: At the moment the idea is to have a PCB for the Arduino, LoRa module and I/O (LEDs, buttons). This way, the exact same design can act as transmitter and receiver with just a change in the software side.
- Redesign the case
