VESC 4.12 doesn't like PPM via Arduino

ESK8 Electronics
,
1

Hey, I have a selfmade VESC 4.12 (currently) using Ackmaniacs modded FW 3.102. Somehow, I am not able to make the VESC eat my PPM signal. I am using an Arduino Nano v3 and generate the signal using the Servo library. This is for testing purposes and thus very (very) basic.

#include <Servo.h>

#define serial Serial

Servo ppm;
int poti = A0;
int poti_wert = 0;
int ppm_wert = 0;
int pwm = 6;

void setup() {

pinMode(6, OUTPUT);  
serial.begin(115200);
ppm.attach(5, 1000, 2000);


}

void loop() {

poti_wert = analogRead(poti);
delay(1);
analogWrite(pwm, poti_wert / 4);
poti_wert = map(poti_wert, 0, 1023, 1000, 2000);
ppm.writeMicroseconds(poti_wert);
serial.println(poti_wert);
delay(1);
}

Here is what the ESC-Tool reading looks like: nano_ppm

A simple PWM output via analogWrite doesn’t work at all…

I would really appreciate advise on how to get a clean reading.

Thanks and greetings :slight_smile:

2

You are doing it wrong… You should be writing servo commands not analogue write.

Check for @solidgeeks remote or mine both run arduinos.

3

Thanks for the reply. I bet I’m doing something wrong :wink:. Just don’t exactly know what. Isn’t the ppm.writeMicroseconds function what I need? I had a look at solidgeeks remote and as well compared my code with yours. I still don’t get the important difference.

Btw.: Scoping the signal doesn’t show any noise :face_with_raised_eyebrow:

4

Make sure you’re looking Solid’s developer branch not master

5

Why do you have both an analogwrite and a millisecond write?

6

Testing purposes. Thought it doesn’t hurt to have a look at what happens by passing over a simple PWM - turned out it doesn’t work at all :roll_eyes: Right now I’m digging through solidgeeks dev branch as @Jc06505n recommended. But as far as I can tell, he uses this here

esc.attach(throttlePin);
esc.writeMicroseconds( map(throttle, 0, 1023, 1000, 2000) );

what should be pretty much be the same I’m doing (or trying to do?).

7

Why don’t you start off with the simple sweep or knob example and that way you can make sure it works first, then try modifying it

8

Thanks @pat.speed, but thats what I did. Maybe I should be more precise about what the problem is. I am able to scale the ppm signal in the defined range. I can see it in the ESC-Tool reading (shown above, the reading moves from left to right and back as I am turning the potentiometer) and I can verify it using a scope. This nervous jittering around +/-5% of the signal is what I am worried about :neutral_face:

9

Ahhhb nah that’s pretty normal, even happens a bit on my remote. Make sure you set the neutral deadband around 15% and you’ll be fine. Have you tested it with motors connected?

10

No, too afraid of scary things that might happen :roll_eyes: Ok, give me a minute…

Update: Well, you are right. Works. Seems like my problem was located somewhere else. What happened in this thread stays in this thread :shushing_face:

Thanks again guys!

11

It does look a little bit jumpy-er than usual, maybe there is a way to kinda smooth out the pulses from the arduino? I’m not very good with arduino but maybe a filter of some sort to slow the pulses

12

Indeed. Now I got some soldering to do and maybe give it a test ride tomorrow. I get back here after that :slight_smile:

2 Likes
13

I am trying the same with a VESC 6.4. My code reliabily makes a small servo move, but when I connect gnd and Signal of the VESC, nothing happens. The BLDC tool shows no values. Not even random ones.

14

I’m back. Everything went pretty well. Had to increase the deadband to 17% though. Approx 10km ride with no issues at all.

@MaxMaker I don’t know your wiring but I power my arduino based receiver via a BEC due to the vesc’s power supply beeing very noisy. I only connected the ppm wire to the vesc. In your case you mos defnhave to connect 5V in addition to GND and signal ;D. I’m planing on soldering a vesc 6 but for now I can’t say much about the 6’s power supply.

15

So my VESC is connected to the Arduino only via Gnd and Signal. I know I cannot connect the +5V since then two power supplies are fighting each others.

I just cannot get any readings in the throttle mapping part of the VESC tool. Very frustrating. I am out of ideas…

16

@AchimWurm would suggest taking out the serial communication once you’re done debugging through the serial port and see if it helps smooth out the signals getting sent to the VESC, the Serial communication seems to add a surprising amount of overhead. @MaxMaker would suggest sharing your arduino code so others can give it a go or let you know if something is weird in the code that might cause issues. Make sure in the VESC tool you have real time app data active as well if you aren’t seeing any motion whatsoever. Last thing I’d suggest is getting your hand on an oscilloscope either borrow one or get one of the ultracheap ones on amazon or elsewhere (jbtek brand ones are very cheap, I built a kit one for fun and it works great for these types of simple things)

17

Here is a video of the Setup with proof that PPM is working at least on a servo.

1 Like
18

Of course. No bloat code active :relieved: Stuff for further investigation… But for now I’m trying to figure why the vesc doesn’t like 10s. But thats a whole nother story. Other stuff for another thread :wink:

1 Like
19

As @wafflejock mensioned - can you provide your arduino code and some sort of wiring diagram? Like a table of what goes to what.

20

Okay so at this point my only guess is something in the vesc tool isn’t turned on… I think you only need “RT/App” turned on… I need to hook up my old vesc here though and upgrade the firmware to see what exactly happens with that wizard.