Hey guys, Can anybody recommend a decent, cheap 3-channel radio? I'm thinking along the lines of one of those pistol grip car radios. This is for a little side project ship, I only need a channel for the rudder, ESC (need reverse), and an on/off for the pump. Although this is a combat ship and will be built under the rule set I am developing, its just a little play thing... mostly built to get my feet wet and to tow targets as its pathetic armament of 6-pdrs. is too puny to arm. I see a lot of radios on eBay that seem like good buys ($50-80), I just want to make sure that I get something I can keep using with around other people (meaning correct frequency, etc.) Would say something like a basic Traxxas radio work just fine? Thanks in advance.
As long as it's a ground legal frequency, any old radio will do. I'd check the frequency that the particular one you're looking at comes with, although many can be changed by swapping crystals. I bought a 4-channel FM radio from Tower Hobby in the price range you're talking about. Even if prices have gone up a little since I bought it, still a bargain.
Yeah, 75MHz. Most of the 3-ch radios looked as expensive or more than the 4-ch ones, that's part of what drove me towards the 4-ch. Also, being able to use it on any of my ships up to cruiser was a motivator. I thought of a question for you... with your 1/72 ships running lots of stuff, what's a 3-ch going to do for you? Testing? I have been looking at how I want to control my 1/96 BB and even if there were a way to multiplex commands on the 3rd channel, it wouldn't be very smooth. Even using onboard AI for ranging and coordinating the main turrets (i.e. captain on shore sets target bearing and the guns do the rest), I need channels for pump and secondaries and the captain's ice cream machine in the wardroom... Oh, I'm leaving for work in a half hour, so I won't be back on till 9PM EST, but I'll be up all night to talk Assuming no code blues!
I didn't say this one was a big ship [] Its the Uss Katahdin, the quirky ram built by the US in the 1890's. Like I said before its armament of 6 pdrs. is too puny to arm. Its only weapon is its bow, but its so slow at 16 knots it could only hope to polish off crippled ships, and even then its it in danger of peppered with small caliber, RF guns. I always liked the looks of it, and CAA (the French Archives) has a good set of free plans, so I figured what the heck, I can at least use it to tow targets. I too was starting to notice that a 4-channel cheapie radio would cost about the same. I have an ancient 4-channel AM Futaba lying around that is 75 mhz, would an AM radio work? Its an old $20 ebay score, but I need some kind of power source for the reciever. I have no moral issues hacking out one of the gimbles to replace with a couple of buttons.
It would depend on how 'ancient' your ancient is If it's older than mid-80's, then it's too broad a bandwidth to be used. Newer than that (my 2-channel target radio is from 1984 and legal) is fine. The 2-ch AM I got from tower for a second target radio was like $40 on sale. I have been contemplating how to run my battleship most efficiently, channel-wise. I'm considering using an analog channel to send target bearing info, and was on the fence about using another for a multiplexed signal for the pump, lights, and other random things. I'm looking at the Parallax Propeller chip as the onboard cpu. It's nice because the hub processor can receive the signal, and then farm out aiming and elevating to some of the subprocessors, and the rangefinder can be run by another subprocessor that routes data back to the others thru the hub (or just changes elevation itself).
It may be mid 80's ancient... But on closer inspection the reciever may be FUBAR'D so I'm thinking I might as well just buy a new one from someplace like Tower Hobbies. Tug, I've been thinking about large scale BB control systems as well. I agree some kind of hub processor is the way to go, farming out various commands to a smaller, simpler microcontroller. I think its best to just ditch the off the shelf RC Radio completely. But in that case I need to learn a lot more about custom robotics.
Look at the Propeller chip and let me know your thoughts... I was looking at how to use a COTS radio system, modified, but I'm leaning towards using amateur radio 2m or 440MHz HTs (handy-talkies) for a data link, with a custom interface on the control end. The size of the HT doesn't matter much on the transmit side, they're all pretty human-portable, but for the ship-end, I've looked at the little 340mW HTs that are near credit-card size, maybe 1/2" thick. Not a lot of transmit power, but they receive just fine.
OK, it is NOT a three channel radio, it is 6. But you can get a Vex transmitter for $29.95 from All Electronics, sometimes cheaper on E-bay. It is a very nice programmable 6 channel radio. BUT, there are some gotchas, and only the transmitter is usable, you will need to add a RX. But for the price, it is a really good radio. There is a more full discussion of the pros and cons of this radio on the Visit this site site knowledgebase in the How To section. Yes, the Traxxas 3 channel TX will work (I have a couple), but you are limited to 5 or 6 27Mhz frequencies, and there is no End Point Adjustment or other nice features, like mixes etc., that you will find on the Vex. Oh, one other thought (limited range, though, 90 ft max). The c6c controller form Cheap Control Systems. It uses a wireless playstation2 controller to give you 6 channels in your ship. It is not particularly tiny, but mine works a treat. If I could increase the range, now..... Cheers,
Tug, I must confess I know very little about building a custom transmitter/microcontroller system... I have a working understanding of programing, having worked with BASIC and PASCAL back in highschool (a decade ago). But getting from idea "A" to finished product "C" is another matter. My goal is having nearly every system on a ship controlled by a hub processor (aiming, firing, damage control (pumps), and other misc. systems) that recieves and sends commands to other microcontrollers. I would also like a system that sends info back to the hand held controller certain bits of information, say which weapons are not responding to commands or are out of ammo. I would also like an automatic shut down of any weapons that fail to respond to commands (ex. not rotating on target) to shut down, simulating a knocked out gun.
Without doing a custom radio, the easiest way (i think...) is to use a regular 6-channel radio, using 2 channels for drive and rudder, and wiring in a custom microcontroller-based expander than multiplexes several inputs into a signal that uses one or two of the other channels to send target bearing, firing commands, pump status bit (0 or 1 = on or off), lights, etc. On the receiving end, your stock receiver gets the signals, and the black box on the ship (the AI) is plugged into the same one or two channels that you're using on the transmitter (obviously) so that it can receive the multiplexed signal and interpret it to make things happen onboard. For giggles, the signal line in on the AI should use an optocoupler to prevent damage if something goes horribly wrong on the receiver side. My first shipboard AI will obviously be called Cortana
My local hobby shop has a three channel, Trans, Rx and two servos all for $49.99. I can not remember if crystals were included.. Check out http://www.awesomerchobbies.com/
I did not see the radio you were talking about on that site. I doubt, for that price, that it has EPA's or much trim, though. Usually that would be a pretty basic radio, which I would find inadequate (or barely adequate) even for a lowly transport. By the way, I saw the Propellor chip mentioned. My understanding from both the manufacturer literature and some of the intrepid users is that the Propellor is not a beginner microcontroller. The very inexpensive Picaxe, which requires only 2 resistors and a serial cable to program (no special programmer boards), the BASIC programming interface is free for the download (including the manual and simulator), is designed for beginners and has great support. And, the chips are around $3-12 depending on the chip. Cheers,
Last I looked, the Vex TX is still available for $29.95 from All Electronics, but be sure and read the info on this radio on the NTXBG How To section to avoid the gotchas if you are a newbie. Or even if you are experienced. For instance, you will still need to get an RX. Cheers,
