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Getting started - help with shopping list


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I've built a fair few small things in my time, and want to have a go at small R/C road vehicles.  Start in 4mm scale, but may head to 2mm eventually.  

I'm fine on the small engineering stuff, soldering, etc..  I've watched a fair few videos, often of German models, and seen (and driven) some of Giles' 7mm models.   

But, I have no knowledge on R/C equipment.   So, need help making a shopping list. 

 

 

So, what do I need to do a first vehicle ? 

 

Transmitter - no idea, see them advertised from £10 to £hundreds.   Need advice on that - it may be the biggest "dunno what to get" problem.

 

Receiving module - seems that Deltang stuff is usually recommended.  I can just about make sense of various lists.  Clearly need a receiver with a H-bridge output (so have forward/reverse motor).  Not sure whether to do steering with a Servo (big, even the micro ones, but simple off-shelf) or an Actuator (smaller, but mechanism to add, and less effective power), but think I have to make that choice on the receiving module.

 

Battery - I guess Lipo cell to fit available space, plus specific charger for them ? 

 

Driver motor.  The easy bit, I'm back in the motor-gearbox stuff I already understand.  Just need to match motor voltage with battery/receiver output. 

 

Anything else ?  (Apart from the pack of roundtuits and tube of elbow grease  ). 

 

 

Help with the list is needed.   Thanks,

 

 

Nigel

 

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Hello Nigel

 

I am guessing you've already seen these threads but just in case, they are both for 4mm scale RC vehicles people are making that might shed some light on the parts required.

 

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4 hours ago, Nigelcliffe said:

But, I have no knowledge on R/C equipment.   So, need help making a shopping list. 

 

So, what do I need to do a first vehicle ? 

 

I am not aware of any "receivers" smaller than the Deltang products. I put the word "receivers" in quotes because the Deltang module is actually a combination of wireless transceiver, microprocessor and h-bridge for motor control.

 

If you are going to use Deltang receivers then I would also recommend using transmitters recommended by Deltang. Apart from the Deltang units I believe some regular Spektrum RC transmitters can be used.

 

I have built much cheaper "receivers" for my model trains but they are much bigger than the Deltang modules and would probably be too big for 00 scale road vehicles unless you could put them in, for example, a van body. My devices use nRF24L01+ wireless transceivers which are functionally similar to, but incompatible with, the Cypress devices used by Deltang.

 

...R

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2 hours ago, Robin2 said:

I am not aware of any "receivers" smaller than the Deltang products. I put the word "receivers" in quotes because the Deltang module is actually a combination of wireless transceiver, microprocessor and h-bridge for motor control.

 

If you are going to use Deltang receivers then I would also recommend using transmitters recommended by Deltang. Apart from the Deltang units I believe some regular Spektrum RC transmitters can be used.

 

 

Thanks,  your posting gives me a few clues - not all transmitters work with all receivers (which isn't something I've found said clearly elsewhere).    

 

Unfortunately, Deltang's website is short on transmitter recommendations; there is one off-the-shelf I could identify in photos, but appears to be unobtainable new and hard to find s/hand.   Or there are Deltang's transmitter components (build your own), which is fine, but its not my first choice to start with two home assembled things (transmitter and receiving/vehicle) and not have a clue as to which isn't working !

 

 

- Nigel

 

 

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If you are considering a Deltang receiver (Rx) note that they use the Spektrum DSM2 radio control protocols as do the Deltang transmitters (Tx). If you find an alternative transmitter make sure it can handle the DSM2 protocol which is older than the present DSMX protocol, although older the DSM2 protocol can control all the stuff you need. 

 

Building a TX kit should not be too difficult as the Tx2 transmitter core is supplied complete and you are basically connecting up the switches and potentiometer(s) and adding various resistors. You can buy the Tx2 transmitter core for about £20 and supply the other components yourself.

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8 hours ago, Nigelcliffe said:

 

not my first choice to start with two home assembled things (transmitter and receiving/vehicle) and not have a clue as to which isn't working !

 

Just to add to what @wasdavetheroad has said, the wireless part of the kit is fully built when you get it. All that is required is to connect the other components.

 

It might be worth talking to Micron who are one of the Deltang retailers.

 

...R

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Thanks wasdavetheroad, Robin & Corbs.    Probably self-build a Tx2 is the reliable route, rather than mess around trying to find stuff talking various protocols.

 

I have tried contacting Micron but not received any reply, which doesn't instill confidence.  Hence asking here.

 

 

Nigel

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Hi Nigel,

 

I think the Deltang receivers are probably the only ones commercially available that will do what you want in the smaller scales like 4 mm.  They are pretty widely used both in the Uk and Germany for this sort of thing.

 

They use DSM2 and some use the later DSMX as well, as has been said.   DSM2 is fine.  You need a compatible transmitter, the Deltang ones are relatively inexpensive and will do what you want.  Some aircraft ones are also compatible but you will be driving the vehicle with joysticks which may not be as intuitive.  Most aircraft ones are more expensive, they have a lot more bells and whistles that you will probably not need. There are one or two very basic ones that are sometimes available and cheaper than the Deltang units.

 

The choice of receiver depends on, first, what voltage you want to run the motor on.  Up to 6v ie one LiPo cell, you can use the very small Rx4 series.  Higher voltages , ie two or more cells, need the slightly bigger Rx6 series.  After that it depends on what additional controls you need - do you need servo outputs for steering, logic outputs for lights, horn etc., or another motor output for a winch, for example.

 

Looking  at Deltang transmitters, you might consider the Tx22 and similar which have the ability to control up to 12 models for little extra cost.

 

Micron are very good, and usually pretty responsive, give them another try.

 

Hope this helps

 

Frank

 

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For 4mm, here's a valuable source of stuff...

 

https://www.sol-expert-group.de

 

And i have a couple of these transmitters, and find them very good...

 

https://www.robotbirds.co.uk/default/jumper-t8sg-multi-protocil-transmittter.html   note - I got one from Micron with both sticks sprung to centre.... most of course are configured aircraft style.

 

Yes to Deltang from Micron. I also now always fit their inline fuses for only 50p each or whatever...

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This has been a fascinating topic, and thank you for starting. Would it also be possible to be pointed in the right direction for a wiring diagram for a vehicle please. I’m a bit confused with the switch and charging arrangement.

 

Thank you for any help anyone can give please.

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I agree with the above.

I generally use the Deltang 45 and 43. Depending on how many outputs and just how tiny I need to get. I have also tried the small 6xs for the more advanced functions, but not personally made good use for them. I think this is because they are more targeted at the trains.

 

If you are undecided between actuators and servos.

All of the 4x's have the 2F outputs you need for actuator control. But the F2 pin on the 43 is much harder to solder to, fine if you are practiced on very small pads but I would avoid unless you need the rest of the functionality. 

 

Servos are much easier to use and give a much better variable control and relatively much more force available. If you are just starting I would suggest do your first build with one and then move on to actuators. You can cut servos down a little but in reality you are more rearranging the components into a more useful and flexible shape,  this is still very useful if you are pushing the space limits. 

Actuators are much smaller, I have used the smallest of the complete actuators from Micron. But not the one which is just coil and magnets where you supply the pivot/structure etc. 

The force supplied by the actuator is just enough to steer the scammel scarab, but bumps in the road surface knock it off course easily. The gears of a servo provide a lot of resistance to such external loads.

It also gives most of its travel in the first 1/4 of stick travel, so whilst fully variable, it is very sensitive. They also seem to draw more power from your batter than a servo.

 

I would use a servo anywhere that will fit, move down to actuators only when you run out of space.

 

Lastly, and not on your list is shape memory alloy. SMA this is also available as nitinol. You power it using the F outputs. Its very tricky to handle, but some of the really small vehicles in Germany use it, including some of the N gauge ones. It requires very little volume but relatively long length. I mention it because you will see it around, and its the smallest, but I would not recommend it until you have really got the hang of everything else. (if then).

 

Finally, the biggest consumer of space is the battery. Really small ones are hard to find. Giles has a reasonable range available to him in O gauge, in OO, a lorry is reasonable but vans and cars, there are only a few, in N you will be really struggling. Less than 70mAh will give a very short run time and the maximum discharge current is directly related to the mAh capacity multiplied by the 'C' rating, again this makes it harder to find suitable components. Before you start using Lipos make sure you read up and understand them and their risks. You really dont want to get them wrong. (sorry if you know all this already)

Micron have a reasonable range but there are a few others, and the small sizes seem to come and go. The indoor rc aircraft and drone suppliers appear to be the most consistant.

 

I hope that all helps. Welcome to our very specialised corner of the hobby. Its a lot of fun!

 

 

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39608740492_a02074a9b7_b.jpg

2018-01-11_10-19-56 by giles favell, on Flickr

 

Here's the wiring that I use..... I'm indicating a Jack socket for charging, bot of course you can use any arrangement that suits you..... Nowadays I fit an in-line resettable fuse in the positive between the  battery and the charging socket. They are bought from Micron very cheaply, and are extremely small. The switch goes in the positive between the charging socket and the receiver.

 

At the moment, the smallest servos you can get are 1.7g and are easily obtainable either from Micron or EBay. Be warned, they are only rated for 4.2v I think, so can only be used with a single Lipo. I have found that a conventional servo is more powerful than a linear servo.

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Fantastic Giles, thank you so much for posting. I was a big admirer of your superb work at Littlehampton, you have inspired me to take the plunge. I contacted Andy at Micron as we discussed, and he has been extremely helpful with my first order.

 

Quick question, the 3 bars in the middle is this the symbol for the charging point please? Sorry if this is a daft and obvious question to others!

 

Thank you in advance.

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Not a daft question at all!!!! Yes it is.... for most things I use a 2.5mm jack for charging, as this automatically disconnects the receiver from the circuit when you plug it in (regardless of the switch). There is probably a standard symbol for a jack plug but I'm sure this isn't it!!!

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Another quick question if possible please. On a Deltang RX45 where the P pads are set up for light functions, would you happen to know the output voltage for the LEDs please? Would I need to be concerned with resistors?

 

As you can possibly tell my o level physics was a long long time ago.....

 

Thank you again.

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And a maximum of 8ma for the RX45 But to be honest. Most modern LEDs, especially the tiny ones you will want for this will be like a search light at that current. A 10k ohm will give a nice gentle glow with a surface mount led. A bit lower if you are building something modern. 

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Ooh, another patron of the art of making tiny RC stuff :D 

 

Transmitters I use are the Orange TX6i, available from HobbyKing for about £70, or the Jumper T8SG, available from Micron for about £90. The Jumper is smaller and more versatile/configurable but the Orange has really good control sticks and runs on AA batteries. I've not found anything cheaper that has the functions you will need.

 

Steering axle is impossible to make in OO I'd guess, but you can get different width ones from various places. Sol-Expert has a few, also MCCCarParts in Holland and KKPMO in Poland do them.

 

If you want a kit containing all the bits you need for a OO gauge van, I sell these for £110 although I am short of a few parts just at the moment. Search @JPModels2018 on Facebook for more info :) 

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  • 2 weeks later...

Thanks for the various comments in this thread.   I've now got contact with Micron, which is good, and I've got most of the way to a shopping list of parts. 

 

The transmitter options are particularly helpful, thanks for those. 

 

It will be a while before I get stuff put together, first a few test rigs, then a monstrous test vehicle, and finally something which looks like a proper model. 

 

 

- Nigel

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Nigel,

 

If you are anywhere near Mansfield on Saturday 13th there is an 009 show at Portland College and I will have my demonstration of radio control there.  Come and have a chat and a play!

 

Frank

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  • 5 months later...

Its taken a while, but I've now got a vehicle running.  A Newcastle bus in N/2mm scale, which might find its way to a reasonably well known 2mm model which has a Newcastle bus garage in one corner:

 

Video of RC bus on YouTube

 

Main bits: 

  • motor/gearbox with 64:1 final drive from Microantriebe,  two pairs of back-to-back diodes to reduce voltage to motor, and may add a third pair.
  • front axle and wheels are Faller N gauge bus spare parts,  steering actuator is a Plantraco small coil actuator,  home made brass linkage replaces the Faller magnet-following arm on the steering parts, and provides link to the actuator.   
  • Deltang receiver and small Lipo battery.   
  • Chassis mostly 40-thou plasticard.  

And not in the bus, a Deltang transmitter bought as a complete assembled unit from Micron and a Lipo battery charger.    

 

The packaging inside the bus isn't very compact as these things go, so there is scope to fit a smaller vehicle.   As a first build, it has a lot of space: the motor/gearbox is held in with various removable wedges to allow things to be dismantled; the wires are not really in ideal routes; there is a lot of plasticard surplus to allow fine-tuning of fit;  and so on.     Those all take up space. 

 

 

- Nigel

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Well done! There's nothing quite like achieving a project like this..... you will find yourself searching out different gear motor combinations (my favourite gives about 90rmp at at 3.7 volts). It's a rather addictive side to the hobby.....

 

If you are creating more, I can provide you with steering axles if you wish.

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