Alright, let’s get this show on the road. I am currently working on a high-performance, top-tier racing spec remote control design that uses modular internal components that can easily be reconfigured into different shapes/styles/sizes. I feel the remote and control over your throttle is one of the most important aspects of riding, and while there are some great low cost open source options out there I’d like to do something a bit different.
…I’m going to need a better name.
I’ll rip this band-aid off now to properly set expectations- These are going to be expensive as they will be hand-built and I’m not cutting corners on component choices. I’m certainly open to selling parts kits and looking at ways of reducing cost, but I designed this with quality & performance taking priority over any cost-savings. We’re likely looking at a $200-250 retail price for a ‘pre-assembled, ready-to-run’ Remote & Receiver. Don’t quote me on that. I promise nothing at this point.
I will be releasing the entire project open source under a Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) license. The only caveat being is that I don’t yet have permission from the OEM to release the source of the thumbwheel sensor I am using, however the design can accommodate different analog sensor inputs for the throttle.
Generally speaking I tend to wait until I’m finished with a project before posting about it, but my intention here is to release this project to the community so I’d like to loop you guys in for feedback earlier in my design process. This is very early in my development cycle, I only started digging into this seriously over the last 2 weeks, though I am just about ready to send off for my first round of prototype PCBs once I finalize where the LCD placement will be.
So with that said, here are the specs and proposed development road map.
Phase 1 - Remote Reference Design & Basic Receiver
Throttle Sensor - military-spec (literally from a DOD contracted flight controls manufacturer) high-precision hall-effect thumbwheel sensor, impact resistant, IP-67. Amazing hand-feel, customization options for different trigger/thumbsticks & spring resistance. I’ll ping @SeanHacker & @Spiritrunner47 to chime in with feedback as they’ve held my prototype in hand. The biggest catch here is these things are pretty expensive @ $70-80 depending on configuration.
Modular Internal Electronics - Currently my PCB design is roughly the shape/layout of an 18650 cell, with two analog inputs for the option of a 2nd throttle/thumbwheel if you’re feeling saucy. Analog inputs from the hall effect throttle sensors are interfaced via a 12-bit ADC. I am actually using an 18650 cell for power currently, with an integrated li-ion charger/boost circuit, but I’d like to leave this somewhat flexible in the design. Buttons will probably be kept to a minimum by I would like basic mode switching and an optional, programmable Deadman/cruise control trigger button at well.
Radio Comms Link - 802.15.4 Xbee3 Radio Modules. I’ve used the Xbee S2C & 3 in a variety of environments professionally, they’re essentially built for high-interference industrial environments. All the bells & whistles you’d expect from a modern, higher end radio comms module. Currently for testing, I’ve simply created a 115k-250k baudrate transparent UART link from the VESC to the remote using a pair of modules. I must emphasize that this is still very early in testing, I am not set on using these if they don’t hold up in real-world performance. The biggest concern with transporting any more complex data structure like this is latency, though based on early testing I’m seeing around 30-35ms round trip time @ 115200 baud, without optimizations. Again, as critical as the comms link is this will still need a lot more testing, I just have a lot of experience using these modules so they’re an easy go-to to get up and running quickly. So far they are working really well, but it needs to be thoroughly tested before I’ll give it a bulletproof stamp. (PS: If your feedback is that you heard ‘Xbees suck’ I ask that your experience with them extend beyond using older series modules with Zigbee firmware, default settings, on your highschool’s FIRST team. They require application/environmental specific configuration to get functioning well, but they do function well when setup correctly).
0.9" Color LCD Display/Integrated ESP8266EX SoC/WiFi/SD Card - Currently prototyping with a 4D Systems IOD-09 module. I intend on keeping the display clean, simple, graphical. Currently I have it displaying speed, board battery, remote battery, odo. Obviously additional info can be added on other screens, etc. Just not a huge priority right now until other bring-up is done. I’ll expand on the WiFi/SD in Phase 2.
Receiver - Currently the plan is for a very basic receiver module that just interfaces directly to UART, but keeps costs down to about $25 per receiver for multi-board support. I have the ability to add PPM/PWM, but it’s lower on my list of priorities and may end up getting included in the Advanced Receiver project.
Remote Grip/Enclosure Design Styles - ‘Nano Style’, ‘Puck Style’ & ‘Trigger Style’ are the three I chose to start with. The intent here is to allow for people to modify and/or design their own enclosures, but I wanted to make a few basic reference designs available to get people started or to offer to those that don’t have modeling/printing abilities. These are intended to be solid-piece prints with access panels for the battery/LCD on the rear and a robust charging port (how many of you have broken a microUSB port off?). Here are a few first-pass sketches as reference. Please note- I am aware I will need to shift the LCD around, these are nowhere near final and will require a good number of print iterations to get the sizing & handfeel correct. Purely for example, but I am printing up a shelled dummy of the red ‘Nano Style’ in Nylon 910 currently to get started.
PS: I promise I actually made a consious effort to make them look less like Dongs. Late nights tho
Phase 2 - Onboard telemetry logging to SD card/WiFi API for App sync
This will be the second stage of development after basic functionally is rock solid on the remote. Concept here is that the board/remote should always be logging internally and shouldn’t depend upon a Bluetooth tether to your phone. I already have the ESP2866 setup to host a webpage on demand for configuration/tuning, this will be extended as a web API that can be turned on as needed to ’Sync’ your remote to a logging app not dissimilar from how a FitBit style fitness tracker logs/syncs up. I would like for the board & remote to be self contained and not require a phone to be on-hand and connected in order to log ride metrics. SD card onboard the esp board gives us plenty of space for logs.
Phase 3 - Advanced Receiver This will not replace the basic receiver, rather be an advanced option further down the line. Features will include dual PPM/PWM outputs to give additional throttle output options to the ESC or for compatibility with non-VESC based ESC. UART will still be required for full telemetry obviously. Also want to add a bank of 12v mosfets to control lights, horn, etc. Open to suggestions on additional features you guys would like to see here.
WIP - I’ll update with more in a bit, gonna go skate!