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

Posted: Dec 11 2016 10:04pm
by deronmoped
I found a 5K ohm thumb throttle. Still expensive though.
http://www.thesuperkids.com/curriethrottle.html
Looks like the potentiometer style throttles were used in these: : Early Currie, GT, Mongoose and schwinn brand scooters with brushless motor.

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

Posted: Dec 13 2016 12:10pm
by deronmoped
Here is a 5K ohm thumb throttle on Ebay for $27.00 with free shipping.
http://www.ebay.com/itm/0-5k-Pot-Thumb- ... xyRNJShrni

Here is the manual for the 5K ohm Magura potentiometer type throttle.
http://home.earthlink.net/~hcf-305userf ... -sheet.pdf

Here is the barebones all you need potentiometer, 50 degrees, spring return, build your own throttle. This is 10K ohms which matches the servo testers resistance better, which is 10.5k ohms. You can use a cable type throttle (inexpensive) to operate this pot, allows remote location of the pot.
http://www.4qd.co.uk/product/bell-throttle-pot/

Here is a idea, joystick 10K ohm pot. Inexpensive, do not know if it has spring return, what degrees of travel give the 10K.
https://www.amazon.com/MDFLY-10K-JoySti ... entiometer

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

Posted: Mar 11 2017 5:42am
by Ecyclist
Jeremy Harris wrote:
Hillhater wrote: A further thought on this Hall throttle issue..
..this Turnigy servo tester has a "Auto" function (firmware ?) that will automatically run the ESC through the full speed range .. bypassing the potentiometer.
that would suggest that there is something else, other than the 0-5k pot, "on board" to control the output.
Maybe the Hall throttle is somehow using that firmware system ?? ( just random thoughts :? )
All the servo testers that I've seen recently have used a small microcontroller to generate the PPM signal for the servo. They often have two switchable options, one that uses the pot to control the waveform and one where the microcontroller just cycles through the allowable range.

The pot connections vary from one type of servo tester to another. I have one here that just uses two connections from the pot so is effectively just reading resistance - this wouldn't mate up with a Hall throttle well. I have an older one here (from my local model shop, with no brand name) that uses a 10K pot wired to give a 0 to +5V signal to the microcontroller. This may work with a Hall throttle, but the throttle range would probably be wrong, as the Hall throttles usually have about a 1.5 to 3.5V output voltage range when run from a 5V supply.

It's pretty easy to make an interface that will run from the 5V BEC supply and allow a Hall throttle to be used. A simple microcontroller, like the 8 pin Picaxe 08M, will run on +5V, draw negligible current, accept any analogue voltage input in the 0 to 5V range and output a PPM waveform that will directly drive an ESC. All that's needed is a bit of simple code (written in a form of BASIC) that will read the voltage from the throttle and use this to set the PPM signal. This is pretty easy stuff even for someone with no experience of writing code. The pseudo code would look something like this:

Mainloop:
Read ADC ; this read the voltage from the Hall throttle and converts it to a value between 0 and 1023
Subtract zero offset number ;the throttle isn't at 0V when closed, so the offset needs to be subtracted
Multiply or Divide by a factor to get the right SERVOPOS value ; this changes the raw voltage reading to a throttle value
Send throttle value number to SERVOPOS ; this tells a pin on the controller to generate a servo PPM pulse train
GOTO Mainloop ; this just loops the programme back to do the above sequence as fast as possible.

I've already done a board layout for a multipurpose throttle interface, using this controller (http://endless-sphere.com/forums/viewto ... 05#p310462 ). The board is 1" square and just as three throttle wires going in and three wires going out to the ESC (assuming the ESC can provide +5V). The board also has a serial programming port so that the code can be loaded from the free Picaxe programming utility to the chip. To be honest there's no need for a circuit board for something this simple, you could just as easily stick the chip on a small bit of perf board to make the necessary connections, maybe potting the thing in a blob of resin or hot melt glue to make it watertight.

I've not got the time to make these things as a production article, but I may be able to sort the code out, test it and publish it so anyone else could make one fairly easily.

Jeremy
This thread is a keeper. Thank you Jeremy and Matt.

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

Posted: Mar 11 2017 6:09am
by bobc
One day I'll do a demo of using an arduino nano to do this job
They are about £2 to buy on ebay and would need a few lines of C writing
They are about 3/4" by 1.5", come ready made and are ready set up for computer control or data logging.

Hardest part of the job would be making 2 connections to the 5V pin.....

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

Posted: Mar 11 2017 10:39am
by Ecyclist
bobc wrote:One day I'll do a demo of using an arduino nano to do this job
They are about £2 to buy on ebay and would need a few lines of C writing
They are about 3/4" by 1.5", come ready made and are ready set up for computer control or data logging.

Hardest part of the job would be making 2 connections to the 5V pin.....
That would be fantastic.
Do you think that the same could be done for running Castle sensorless controller as sensored, once you have RC motor with halls attached?

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

Posted: Apr 10 2017 2:11am
by WelshGriff
Bazaki wrote:
Slowrider wrote:
gwhy! wrote:
Slowrider wrote:Anyone that can help me with where to connect the 5V from the bec to the modded servo tester or is this just not possible ?
just connect the output ( + , gnd ) of the BEC to the + and gnd of the servo tester, you could connect to the +,gnd of the throttle input.

Like this ?

Image

I tried this setup but it is not working yet, what is this jumper ? Just a wire from Ebike throttle signal to ESC + ?

Thanks
I have this servo as well with a cheap thumb throttle, did you get it to work after?

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

Posted: Jun 06 2017 3:27pm
by TheGuiX
Hi !
This is the correct wiring for the servo-tester with non-BEC ESC :
throttlebike.jpg
The jumper 1 is not necessary if the ESC has a BEC

:wink:

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

Posted: Jun 14 2017 10:43am
by Simpleton
Matt, I see you used a Domino throttle on a recent build. Any hints as to wire colors -> pins on the Astro servo tester?

Ah, nevermind, I found a schematic Here

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

Posted: Jun 23 2017 12:04am
by Ecyclist
TheGuiX wrote:Hi !
This is the correct wiring for the servo-tester with non-BEC ESC :
throttlebike.jpg
The jumper 1 is not necessary if the ESC has a BEC

:wink:
What is POT? A potentiometer?

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

Posted: Jun 23 2017 12:15am
by Dauntless
Ecyclist wrote:
bobc wrote:One day I'll do a demo of using an arduino nano to do this job
They are about £2 to buy on ebay and would need a few lines of C writing
They are about 3/4" by 1.5", come ready made and are ready set up for computer control or data logging.

Hardest part of the job would be making 2 connections to the 5V pin.....
That would be fantastic.
Yeah, it would have been. . . .

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

Posted: Jun 23 2017 1:09am
by Ecyclist
Will modified servo tester work with only potentiometer type of throttle or hall type as well?

I got it. It works for either one. That is weird but good news.

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

Posted: Jun 27 2017 8:14am
by WelshGriff
I can't desolder the turnigy servo tester, what the hell of they use on these things, my iron won't melt any of it!

Looking for options on another way to make a throttle, so much hassle just to press a thumb throttle! Lol

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

Posted: Jan 04 2019 8:07am
by dz1sfb
Gave it a shot with an E-sky servo tester, but no joy.

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

Posted: Jan 04 2019 10:57am
by knurf
I successfully followed this instructable:

https://www.instructables.com/id/EBike- ... Motor-ECS/

and got a grin slim throttle https://www.ebikes.ca/t-htwist-slim.html to play along fine with a castle creations hv80. I also tried it with a rotorstar 120amp thing, worked with it too but it kept emitting warning beeps. Drawbacks with this method is the programming of the atmega8 requires some fiddling and a usb programmer tool which costs more than all other components (although cheap at 16 USD).

Another small drawback, compared to using a CA3 or something to ramp the throttle, is a very linear and sharp throttle response.

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

Posted: Jan 06 2019 12:03am
by dz1sfb
knurf wrote:
Jan 04 2019 10:57am
I successfully followed this instructable:

https://www.instructables.com/id/EBike- ... Motor-ECS/

and got a grin slim throttle https://www.ebikes.ca/t-htwist-slim.html to play along fine with a castle creations hv80. I also tried it with a rotorstar 120amp thing, worked with it too but it kept emitting warning beeps. Drawbacks with this method is the programming of the atmega8 requires some fiddling and a usb programmer tool which costs more than all other components (although cheap at 16 USD).

Another small drawback, compared to using a CA3 or something to ramp the throttle, is a very linear and sharp throttle response.
I am wondering about trying an Arduino Pro Mini that I have on hand.

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

Posted: Jan 06 2019 2:35am
by knurf
I am wondering about trying an Arduino Pro Mini that I have on hand.
That is definitely doable, but not with the image or code from the instructable I found. I saw other similar guides for the atmega328 based nano, I stumbled upon them researching this solution, but didn't try them out. Now I don't have the links anymore.

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

Posted: Jan 07 2019 7:07pm
by dz1sfb
knurf wrote:
Jan 06 2019 2:35am
I am wondering about trying an Arduino Pro Mini that I have on hand.
That is definitely doable, but not with the image or code from the instructable I found. I saw other similar guides for the atmega328 based nano, I stumbled upon them researching this solution, but didn't try them out. Now I don't have the links anymore.
I will work on the Arduino Pro Mini solution in tandem with the 3D printed throttle design that houses my Esky servo tester, which is a temporary measure at best.

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

Posted: Jan 08 2019 3:51am
by knurf
http://rztronics.com/control-brushless- ... g-arduino/
There's a more modern way of doing the same thing for you. The code is much more high level and understandable, compared to the atmega8 based solution I went with. Some simple throttle curve ramping shouldn't be hard to implement in any of them, but I'm done fiddling with mine (for now). Maybe the biggest problem for me now is the lack of proper current limiting, since this leaves it to the ESC to limit current and that is not always very configurable or exact.

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

Posted: Jan 08 2019 4:10am
by amberwolf
The Cycle Analyst can both current limit and convert hall or pot throttles to RC PWM throttle, if it helps.

Kind of expensive if you only need it for that, but if you want the various monitoring functions or any of the toher stuff it does.... :)

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

Posted: Jan 08 2019 4:13am
by knurf
Oh yeah I know, but for this project I'm pinching pennies and actively trying to avoid getting yet another CA3 + shunts :D
But I may end up getting one anyway, always nice to have spares..

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

Posted: Apr 24 2019 6:56am
by Quadr8cer12
Hello! Thank you everyone for all the great information on this thread! Helped me mod a servo tester for my set up.

Would these work instead of modifying a servo tester?

https://rover.ebay.com/rover/0/0/0?mpre ... 2551443926

Or this one?

https://rover.ebay.com/rover/0/0/0?mpre ... 2334763033

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

Posted: Apr 24 2019 2:04pm
by fechter
Quadr8cer12 wrote:
Apr 24 2019 6:56am
Hello! Thank you everyone for all the great information on this thread! Helped me mod a servo tester for my set up.

Would these work instead of modifying a servo tester?
No, I don't think so. Those do the opposite conversion.

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

Posted: Apr 25 2019 10:42am
by Quadr8cer12
fechter wrote:
Apr 24 2019 2:04pm
Quadr8cer12 wrote:
Apr 24 2019 6:56am
Hello! Thank you everyone for all the great information on this thread! Helped me mod a servo tester for my set up.

Would these work instead of modifying a servo tester?
No, I don't think so. Those do the opposite conversion.
Darn I was worried this was backwards from what is needed.

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

Posted: Apr 25 2019 8:34pm
by Quadr8cer12