update: I stopped development on this project, for a few reasons:
The handset unit fits in a Nintendo Nunchuck. Assembly is straightforward, but involves a dremel and a lot of relatively fine soldering. Nunchucks cost $10, and the remaining components are about $30-50 in small quantity: LiPo battery ($5ish), radio ($2-5), mcu ($10-20), BMS ($5-10), LED & discrete components (<$1). They take about 1-2h to build. Performance is as good as or better than the Nyko wireless unit. I ultimately made functional prototypes with the NRF24L01 chipset (inexpensive and easy to program) and a 433/915MHz radio (harder to find and program, but better range).
The receiver end is much simpler. It's about as big as wiiceiver, costs about the same ($20 + radio), and is about the same difficulty to produce -- 20-60 minutes of assembly and soldering.
Functionality: as a 2-axis remote it works great, but one of the target applications was for a surfboard. 2.4GHz doesn't penetrate water well at all, so I went to 413/933MHz radios. They work, but still not great through water.
Flexibility: Libraries for the NRF24L01 and 433 / 915MHz radios are *significantly* different. Enough that it's not practical to use one software stack for both.
Based on the combination of the above factors (it's expensive, hard to make, and can't easily support cheap/plentiful radios) I've stopped development. It was a cool project though!
note: working title
Wiiceiver has been awesome -- it lets people use an inexpensive wireless nunchuck + standard ESC to drive their skateboard. But the internet is running out of nunchucks, and there are some features still missing.
Wiiceiver X is a two-module system, controller ("Chuck") + receiver ("Board"):
- wireless, ergonomic, rechargeable handheld controller w/ battery status
- receiver module with battery disconnect, current & voltage measurement, and servo (ESC) output.
- fully hackable: exposed pins on both units, standard NRF24L01+ transmitters, simple bidirectional communication
Wireless Chuck features:
- LEDs for board battery status
- configuration interface for the receiver (same as Wiiceiver's configuration routine)
- channel bonding & checksumming for managing cross-talk: board <-> chuck will share a provate channel, up to 100 channels available
Receiver / Board features:
- LEDs for management / troubleshooting
- channel bonding to a chuck
- on/off ESC power management & voltage monitoring
- up to 4 ESC outputs (any can also serve as BEC connector)
- When will it be available?
- I don't know, I'm working on it now. Probably $75
- How much will it cost?
- see #1
- Can I install it in my own skateboard / go-kart / unicycle project?