You may want to check out eBay for the crystal upgrade kit. I'm another R2Builder and got a few of these radios last year for testing. I managed to find the upgrade kit for around $5.
-- PF astromechbuilder.com astromech.net On Sat, Feb 21, 2009 at 2:21 AM, Retired Rider <tinsmi...@gmail.com> wrote: > > Here is what I found on the VEX site, this I think solves the Rec. > problem. > > http://www.vexrobotics.com/vex-robotics-signal-splitter.shtml > > And for those who want to change the Crystal here is the right ones. > > http://www.vexrobotics.com/vex-robotics-crystal-upgrade-kit.shtml > > George > > On Feb 16, 2:49 pm, SteveH <n1xnx...@gmail.com> wrote: > > Yo, tankers! > > I've just received one of the remarkably cheap Vex radios that are > > going for $9.99 on the surplus market (this one's from Marlin P. Jones > > (www.mpja.com, item number 17044 MI). You did NOT misread that. > > > > NOTE: The receivers for these units DO NOT demultiplex the individual > > PWM channel signals, you must do this externally with a > > microcontroller or a simple logic circuit. Otherwise, it's a "normal" > > R/C unit. > > > > Since I do microcontrollers for fun, this is not a barrier to me. > > > > I am blown away by the excellent build quality and functionality of > > this radio system, folks. The 6-channel transmitter has plug-in TX and > > RX crystals, programmable servo mixing, exponential throws, 6 storable > > control configurations, battery voltage display, a "tether" output > > that bypasses the receiver to test the circuitry the receiver > > controls; all the sorts of things you'd want in a mid-range R/C > > transmitter. It is VERY solidly made, and has 4 actuator buttons on > > the back that are suitable for fire or traverse functions. Vex did a > > VERY nice job on these units; it suggests that their other products > > are also well made. > > > > At $10, this is an incredible bargain. MPJA have 31 in stock as of > > this writing, down from 61 last week. > > > > Downsides: 1) No charger jack for the tranny, gotta use AA NiCd or > > NiMH cells and charge'em separately. 2) Radio range is unknown as yet, > > but given the obvious high quality of the unit, I'd be amazed if the > > range is anything less than the 1/4 mile common to R/C units. 3) Ya > > gotta do your own demux. > > > > It occurs to me that, if there were sufficient interest, this > > transmitter/receiver would combine excellently well with Anvilus' Mini > > Relay Controller or SSR controller (requiring a 5V regulator for power > > and a fairly minor tweak to the Anvilus controller's firmware) and > > Voila! Complete tank control system. (It will also work well with a > > Gumstix Robostix controller, which has lotsa I/O for R/C servos.) > > Since I'll be doing most of this anyway for myself, I would be > > entirely willing to provide the necessary tech data, and probably the > > microcontroller code, to accomplish this feat. Of course, once the > > supply of surplus TX/RX units goes, the design will be an orphan (or > > maybe not; I happen to know that the 3-pin power connector on > > Airtronics VG series receivers outputs the same kind of multiplexed > > pulse stream as the Vex receiver, and other radios may do similarly.) > > > > Now for the other item: I notice on the back page of the MPJA catalog > > item #17265-MD; this is a lead screw assembly with a DC motor and > > incremental feedback encoder, much like one I cobbled together for > > Sancho Panzer's main gun elevate mechanism. At $30, it's not way > > cheap, but it's still well worth considering as an elevate mechanism. > > > > Regards, Steve > > > --~--~---------~--~----~------------~-------~--~----~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~----------~----~----~----~------~----~------~--~---
