RC throttle interface build tutorial........

Discussions related to motors other than hub motors.
This includes R/C motors, botttom bracket, roller and geared drives.

RC throttle interface build tutorial........

Postby recumpence » Sun Aug 09, 2009 6:25 pm

I have had numerous requests for a turn-key throttle solution for RC systems. So, to that end, I am starting this tutorial for the technically challenged who want the basics of how to build a throttle for an RC throttle interface system with off the shelf parts.

Bear in mind, I am not the first to setup a throttle like this, nor am I an electronics engineer. In fact, I am somewhat electronically challenged myself. However, I have been forced to learn some basics for the good of my hobby and the industry as a whole. I want to share a basic throttle layout here for beginners to refer to. This is obviously super simple for the very technically inclined members of our forum. But, it should help those who are not as technically savy. :D

The products I am using here are;

#1 Astro Flight servo tester
#2 Dimention Engineering VHV BEC (Very High Voltage Battery Eliminator Circuit)
#3 Magura twist grip E-throttle

You can use other brands of BEC and servo tester if you desire, especially if you want to save some money. But, these are the items readily available at my local hobby shop. So, that is why I chose them. They are also high quality and work well together.

NOTE: All individual instructions are written in the caption boxes below each picture for reference.
Attachments
step1.jpg
Here are the components layed out as they come in the package.
step1.jpg (139.95 KiB) Viewed 9363 times
step2.jpg
First, remove the board from the Servo Tester case.
step2.jpg (133.25 KiB) Viewed 9363 times
step3.jpg
Next, carefully remove the Potentiometer from the circuit board. Save this part as well as the knob. They can be reused later for an add-on to the throttle if desired (more on that later).
step3.jpg (125.39 KiB) Viewed 9364 times
step4.jpg
Next, flip the board over and locate the solder points from the pottentiometer you just removed.
step4.jpg (167.82 KiB) Viewed 9363 times
step5.jpg
Next, solder the throttle wires to the potentiometer points on the rear of the board as shown. Be sure to use the color combination shown here (black, brown, blue).
step5.jpg (174.49 KiB) Viewed 9359 times
step6.jpg
Now, take the BEC and locate the 3 wire lead coming from it, along with the two (black and red) wires at the rear of the Servo Tester board as shown.
step6.jpg (179.73 KiB) Viewed 9361 times
step7.jpg
Now, using ONLY the red and black wires from the output of the BEC, solder them to the points on the Servo Tester board that originally held the original red and black wires (clip the left over wires that are dangling from the Servo Tester board). The orange (third) wire coming from the BEC is no longer used. I just clip it short.
step7.jpg (166.43 KiB) Viewed 9357 times
layout.jpg
Here you see the Throttle Interface with all wiring completed.
(129.21 KiB) Downloaded 2264 times
1% of the world's population can think "Outside the box". The rest are firmly stuck within the box. Where are you?
User avatar
recumpence
10 GW
10 GW
 
Posts: 4635
Joined: Sat Apr 19, 2008 8:33 am
Location: On Earth right now. That can change at any time, though..........

Re: RC throttle interface build tutorial........

Postby recumpence » Sun Aug 09, 2009 6:32 pm

Next, once all wiring is finished, I normally wrap the BEC in tape, then foil, then tape again. This is to reduce/eliminate RF interfereance from the switching circuit of the BEC. That RF can bother the servo tester and create some glitches.

The bottom picture shows two completed throttles next to each other. The lower throttle has both boards merely taped together (using tape to insulate the two from shorting against each other). Wide heat shrink tubing can be used as well for a more finished look, as well as better durability. The top throttle has both boards mounted in a simple Radio Shack project box.

The throttle is now finished, ready to use! You merely supply 24 to 48 volts to the black and red input wires (the two bare wires hanging out the side) and plug the other wire into your RC controller, and you are ready to go!
Attachments
foilwrap.jpg
Here the foil is wrapped around the BEC. It will be taped next.
foilwrap.jpg (126.47 KiB) Viewed 9343 times
finished1.jpg
Here is a completed throttle. This is the smallest and simplest arrangement with the servo tester and BEC merely taped (or heat shrinked) together. IMPORTANT------ Be sure to wrap the BEC in tape after the foil wrap or the foil will short out the Servo Tester board if they touch!!!!!
finished1.jpg (137.88 KiB) Viewed 9343 times
1% of the world's population can think "Outside the box". The rest are firmly stuck within the box. Where are you?
User avatar
recumpence
10 GW
10 GW
 
Posts: 4635
Joined: Sat Apr 19, 2008 8:33 am
Location: On Earth right now. That can change at any time, though..........

Re: RC throttle interface build tutorial........

Postby recumpence » Sun Aug 09, 2009 6:42 pm

Lastly, I figured a simple way of reusing the Pot that was removed from the Servo Tester board as a throttle end point limiter.

I do not have good pictures of the wiring to do this. But, basically, you run the blue wire (from the Magura throttle) to the second Pot (the one we removed earlier). This wire should go to the center terminal on that removed Pot. Next, you run a separate wire from the terminal to the right of that center pin on the Pot to the terminal on the back of the Servo Tester board that the blue wire should have gone. This, effectively, gives you an adjustable throttle end point.

Now, this end point adjustment is NOT a current limiter. It is a throttle end point adjustment. So, when that Pot is set at 50%, your twist grip throttle will only output 50% at full throttle rotation. This limits the top speed attained and increases throttle resolution making for much smoother throttle response. This is especially helpful for high speed/power setups where you want to be able to limit speed and soften throttle response for a beginner who wants to ride it.

Adjustable throttle is shown to the right of a non-adjustable throttle.

This particular throttle was built for my 12.5kw trike. :D
Attachments
two throttles.jpg
two throttles.jpg (124.9 KiB) Viewed 9328 times
1% of the world's population can think "Outside the box". The rest are firmly stuck within the box. Where are you?
User avatar
recumpence
10 GW
10 GW
 
Posts: 4635
Joined: Sat Apr 19, 2008 8:33 am
Location: On Earth right now. That can change at any time, though..........

Re: RC throttle interface build tutorial........

Postby 12p3phPMDC » Mon Aug 10, 2009 1:03 am

Thanks for posting that Matt...
I'll be picking up a Magura and doing this as well.
What's your opinion of the Magura?

Seems like Magura makes throttles for pull cable throttles too.

I bought a lousy thumb pot throttle that I'm not happy with at all.
It has a weird full throttle catch which is not what you want in a throttle IMHO.
I've gone through great lengths on cars to insure that the throttle never
sticks wide open, and this company built a throttle that
does just that :shock:
Its a low tech cruise control I guess...which may be good for a low power setup.
"If you don't follow your dreams, you might as well be a vegetable." Burt Munro

The reasonable man adapts himself to the world;
the unreasonable one persists in trying to adapt the world to himself.
Therefore all progress depends on the unreasonable man.
-- George Bernard Shaw
User avatar
12p3phPMDC
1 kW
1 kW
 
Posts: 473
Joined: Mon Mar 16, 2009 9:00 pm

Re: RC throttle interface build tutorial........

Postby recumpence » Mon Aug 10, 2009 7:01 am

I have mixed emotions about this twist grip throttle. The quality is OK, I suppose. My beef is the fact that it is all plastic. However, the plastic is thick and well molded. Also the return spring is pretty stiff. Not horribly so, but a touch stiffer than I would normally choose. Other than that, it is really pretty decent. The price is good as well.

Oh, also, I plan to make a thumb attachment for this to make a basic thumb throttle. If you picture cutting this twist grip very short so only 1/2 inch of the twist barrel is left, then add a thumb tap to the remaining twis barrel portion. Pretty simple. It could be cut to half length too for a half throttle like a half grip, twist shifter.

Matt
1% of the world's population can think "Outside the box". The rest are firmly stuck within the box. Where are you?
User avatar
recumpence
10 GW
10 GW
 
Posts: 4635
Joined: Sat Apr 19, 2008 8:33 am
Location: On Earth right now. That can change at any time, though..........

Re: RC throttle interface build tutorial........

Postby 12p3phPMDC » Mon Aug 10, 2009 10:27 am

Awesome,

Thanks for the explanation. I was thinking about the half grip half twist throttle option.
That will let you grip the top part of the handle independently of the throttle.
"If you don't follow your dreams, you might as well be a vegetable." Burt Munro

The reasonable man adapts himself to the world;
the unreasonable one persists in trying to adapt the world to himself.
Therefore all progress depends on the unreasonable man.
-- George Bernard Shaw
User avatar
12p3phPMDC
1 kW
1 kW
 
Posts: 473
Joined: Mon Mar 16, 2009 9:00 pm

Re: RC throttle interface build tutorial........

Postby etard » Mon Aug 10, 2009 11:04 am

Yeah thanks for posting that.

For some reason the twist grip without engine revving feels awkward to me. I think a thumb throttle would be better. Are you selling any of those custom cnc'd thumb throttles like on the pk?
Four wheels moves the body, Two wheels moves the soul
Thanks to Justin @ http://www.ebike.ca He brings the soul to ES
User avatar
etard
10 MW
10 MW
 
Posts: 2143
Joined: Sun Aug 03, 2008 3:28 pm
Location: Redlands, CA

Re: RC throttle interface build tutorial........

Postby mclovin » Mon Aug 10, 2009 11:11 am

Thanks, Matt. This is awesome. It is so much easier to understand how to construct something when I can see what needs to be done.

Cheers.
User avatar
mclovin
100 W
100 W
 
Posts: 184
Joined: Sat Apr 04, 2009 1:19 pm
Location: Seattle

Re: RC throttle interface build tutorial........

Postby recumpence » Tue Aug 11, 2009 7:21 am

Maybe the "Powers that be" can stickfy this thread for future reference. I already put a link in the resources thread, though. :D

Matt
1% of the world's population can think "Outside the box". The rest are firmly stuck within the box. Where are you?
User avatar
recumpence
10 GW
10 GW
 
Posts: 4635
Joined: Sat Apr 19, 2008 8:33 am
Location: On Earth right now. That can change at any time, though..........

Re: RC throttle interface build tutorial........

Postby fechter » Tue Aug 11, 2009 8:19 am

I put a copy of it in the Technical Reference section.
"One test is worth a thousand opinions"
User avatar
fechter
100 GW
100 GW
 
Posts: 10183
Joined: Sun Dec 31, 2006 3:23 pm
Location: California Bay Area, USA


Re: RC throttle interface build tutorial........

Postby recumpence » Tue Aug 11, 2009 11:06 am

Hey Kim,

G'Day Mate! :D

I have to PM you. I am curious how Rhett is doing................

Matt
1% of the world's population can think "Outside the box". The rest are firmly stuck within the box. Where are you?
User avatar
recumpence
10 GW
10 GW
 
Posts: 4635
Joined: Sat Apr 19, 2008 8:33 am
Location: On Earth right now. That can change at any time, though..........

Re: RC throttle interface build tutorial........

Postby Miles » Tue Aug 11, 2009 11:23 am

recumpence wrote: I am curious how Rhett is doing................

Sadly:

http://www.motoredbikes.com/showpost.ph ... stcount=35
User avatar
Miles
100 GW
100 GW
 
Posts: 10829
Joined: Fri Mar 16, 2007 4:15 pm
Location: London UK

Re: RC throttle interface build tutorial........

Postby recumpence » Tue Aug 11, 2009 11:26 am

Wow, I am so sad to hear that.

Hmm, final pic showing him with a Blade CP. Once of my favorite helis! I loved mine.

Matt
1% of the world's population can think "Outside the box". The rest are firmly stuck within the box. Where are you?
User avatar
recumpence
10 GW
10 GW
 
Posts: 4635
Joined: Sat Apr 19, 2008 8:33 am
Location: On Earth right now. That can change at any time, though..........

Re: RC throttle interface build tutorial........

Postby AussieJester » Tue Aug 11, 2009 8:01 pm

recumpence wrote:Hey Kim,

G'Day Mate! :D

I have to PM you. I am curious how Rhett is doing................

Matt


Yes im afraid he passed away week ago ? Matt. Helen and Rhett had previously discussed
quality of life issues in case a situation like this arose and both agreed to pull the plug if it was determined
quality of life would be comprimised, seeing Rhetts injuries were extensive AND to the frontal lobe of the
brain the decisions was made by Helen to take Rhett off like support...very sad indeed he was such a nice bloke
at least he lived a full and productive life, he flew all around the world as a pilot as well as
well as being a tragic RC addict :-) Might very well be the first rider to die on a lecky bike too :-(

RIP Rhett
User avatar
AussieJester
100 GW
100 GW
 
Posts: 9708
Joined: Tue Mar 11, 2008 3:33 am
Location: Perth Western Australia

Re: RC throttle interface build tutorial........

Postby ron van sommeren » Tue Aug 11, 2009 8:42 pm

Servo-tester circuit
http://www.drivecalc.de/
-> Servo Driver eliminating the need for a receiver ...

Vriendelijke groeten ;) Ron
• brushless motor building tips & tricks • diy brushless motor discussion group
• Drive Calculator download & discussion group • int. electric fly-in, Nijmegen, the Netherlands
Last edited by ron van sommeren on Wed Aug 12, 2009 12:14 am, edited 1 time in total.
User avatar
ron van sommeren
100 W
100 W
 
Posts: 106
Joined: Sat Dec 20, 2008 10:49 am
Location: near Nijmegen, Netherlands

Re: RC throttle interface build tutorial........

Postby mclovin » Tue Aug 11, 2009 10:34 pm

After we wire and solder it all up.....is there anything we need to do to the controller? Is there some type of calibration involved? If this sounds like a strange question allow me to clarify.

As I understand it, the FETs allow current to "pass" during the time they are on (duty cycle). If we are into low speed cruising from time to time and barely twist the throttle then the FETs will have a very short duty cycle BUT may still heat up when they are inbetween pulses. Is this correct? If so do we need to ensure a minimum duty cycle - minimum command voltage (oh, like 50% of battery V) or is this a non-issue?

Thanks!
User avatar
mclovin
100 W
100 W
 
Posts: 184
Joined: Sat Apr 04, 2009 1:19 pm
Location: Seattle

Re: RC throttle interface build tutorial........

Postby Grinhill » Tue Aug 11, 2009 10:49 pm

If so do we need to ensure a minimum duty cycle - minimum command voltage (oh, like 50% of battery V) or is this a non-issue?


The throttle pulses aren't used to drive the output stage directly, there's a microcontroller in between in the ESC.

When you first power it up, the ESC looks for a baseline stream of pulses (1 millisecond width) which corresponds to zero throttle. If it sees these pulses, it then goes in to idle (motor stationary, ready to start).

Opening the throttle increases the pulse width proportionately, up to a max of 2 milliseconds, which is what this interface circuit does. The ESC takes care of the rest (i.e. spinning the motor). :D
1995 Giant Hybrid - Zeta2 with 12V 7AH SLA - removed after one year.
2006 Converted Giant to Geared Brushless Rear Hub with 24V 17AH SLA - bike stolen 2007.
2008 Hardtail MTB Disc Brake - lightweight RC/LiPo system.
Grinhill's Medium-power RC-Motor Hardtail build
The Grinhill Mk2 RC-motor drive
Grinhill III - "Supercommuter" featuring Recumpence RC drive
User avatar
Grinhill
10 kW
10 kW
 
Posts: 541
Joined: Thu Jan 22, 2009 11:40 pm
Location: Newcastle, Australia

Re: RC throttle interface build tutorial........

Postby mclovin » Wed Aug 12, 2009 10:46 am

Grinhill wrote:
If so do we need to ensure a minimum duty cycle - minimum command voltage (oh, like 50% of battery V) or is this a non-issue?


The throttle pulses aren't used to drive the output stage directly, there's a microcontroller in between in the ESC.

When you first power it up, the ESC looks for a baseline stream of pulses (1 millisecond width) which corresponds to zero throttle. If it sees these pulses, it then goes in to idle (motor stationary, ready to start).

Opening the throttle increases the pulse width proportionately, up to a max of 2 milliseconds, which is what this interface circuit does. The ESC takes care of the rest (i.e. spinning the motor). :D


I don't want to muck up Matt's tutorial string so I will post this as a seperate topic. Thanks for the info.

Cheers.

***************************************************************

EDIT I started a thread here: http://endless-sphere.com/forums/viewtopic.php?f=28&t=12293
User avatar
mclovin
100 W
100 W
 
Posts: 184
Joined: Sat Apr 04, 2009 1:19 pm
Location: Seattle

Re: RC throttle interface build tutorial........

Postby spinningmagnets » Mon Sep 06, 2010 8:28 pm

The throttle is now finished, ready to use! You merely supply 24 to 48 volts to the black and red input wires...


Matt, sorry for a newbie question, but many of the friction-drive RC builds are using 5S and 6S (18.5V / 22.2V). What changes would I have to make to this Magura throttle adaptation, or is a generic servo-tester really the best option for the lower-powered set-ups? (I don't even know if I'm asking the right question...)
User avatar
spinningmagnets
100 GW
100 GW
 
Posts: 6915
Joined: Fri Dec 21, 2007 10:27 pm
Location: Ft Riley, NE Kansas

Re: RC throttle interface build tutorial........

Postby bandaro » Thu Sep 16, 2010 7:19 am

so if i have a hall effect throttle can i just do the same thing and replace the potentiometer in the tester with the hall or what?

im thinking i wont be able to, but i dont know how either works so im not sure...
User avatar
bandaro
100 W
100 W
 
Posts: 279
Joined: Tue Jun 01, 2010 2:17 am
Location: Canberra, Australia

Re: RC throttle interface build tutorial........

Postby recumpence » Thu Sep 16, 2010 7:34 am

spinningmagnets wrote:
The throttle is now finished, ready to use! You merely supply 24 to 48 volts to the black and red input wires...


Matt, sorry for a newbie question, but many of the friction-drive RC builds are using 5S and 6S (18.5V / 22.2V). What changes would I have to make to this Magura throttle adaptation, or is a generic servo-tester really the best option for the lower-powered set-ups? (I don't even know if I'm asking the right question...)


My current throttle I am building uses a very wide range input regulator. You can go as low as 6 volts input, if I remember correctly.

Matt
1% of the world's population can think "Outside the box". The rest are firmly stuck within the box. Where are you?
User avatar
recumpence
10 GW
10 GW
 
Posts: 4635
Joined: Sat Apr 19, 2008 8:33 am
Location: On Earth right now. That can change at any time, though..........

Re: RC throttle interface build tutorial........

Postby Hillhater » Thu Sep 16, 2010 8:39 am

Just for info and to help anyone starting out ..
I just tackled this ESC /servo tester throttle mod using the Turnigy servo tester .
http://www.hobbycity.com/hobbyking/stor ... rvo_Tester
Image
PS.. initially i thought i had screwed up and got the wrong servo tester. ! but....
This actually proved simpler than the others, requiring only the insertion of one jumper (after removal of the pot) from the input "signal " pin ,to the centre pin of the potentiometer socket.
Image
Image
So when used with an ESC /BEC , you can simply connect the throttle via the "input" socket of the (modified) servo tester and away you go !
Nice simple , quick , clean throttle interface. ! :wink:
To recap..
1) remove the potentiometer.
2) insert a jumper lead from the input signal pin to the potentiometer socket centre pin location.
3) reassemble and plug in your throttle.

And for Spinningmagnets.. this is used on an 18.5 V system, Turnigy Kforce 100A ESC, with the 63-54 motor, and a Hall effect thumb throttle.
Last edited by Hillhater on Thu Sep 16, 2010 8:44 pm, edited 2 times in total.
This forum owes its existence to Justin of ebikes.ca
Hillhater
10 GW
10 GW
 
Posts: 4847
Joined: Tue Aug 03, 2010 10:33 pm
Location: Sydney ..(Hilly part !) .. Australia/ Down under !

Re: RC throttle interface build tutorial........

Postby spinningmagnets » Thu Sep 16, 2010 10:20 am

2) insert a jumper lead from the input signal pin to the potentiometer socket centre pin location.


Hillhater, could you please post a pic of this, perhaps add a red arrow?...

(also...thanks for the reply, Matt!)

edit: WOW! only $6, but they are now back-ordered!!...now waiting for another Hobby king email that stock is back in...

EDIT 2: Thanks for adding the pics! its great to have several RC-throttle options detailed in one thread (with prices, pics, part #'s, and links)
Last edited by spinningmagnets on Thu Sep 16, 2010 9:43 pm, edited 2 times in total.
User avatar
spinningmagnets
100 GW
100 GW
 
Posts: 6915
Joined: Fri Dec 21, 2007 10:27 pm
Location: Ft Riley, NE Kansas

Re: RC throttle interface build tutorial........

Postby Byte » Thu Sep 16, 2010 11:39 am

Don't you need a servo tester with a 5K pot to use it? This one has a 9.35K pot I believe.
Bergli
Turnigy 80-100 130kv
10S 16Ah LiPo
Castle Creations HV 160
User avatar
Byte
100 W
100 W
 
Posts: 296
Joined: Thu Mar 04, 2010 9:39 am
Location: Venlo, Netherlands

Next

Return to E-Bike Non-hub Motor Drives

Who is online

Users browsing this forum: astmacca, Google [Bot] and 8 guests