@Darathian, I have not got around to doing this mod yet, as I have been working on the ALTAIR arms and converting everything over to the EZB v4. This simple mod should work as the Kangaroo problem is that it cannot cope with the high number of pulses coming out of the encoders, this cct halves these pulses so the kangaroo can operate within its design parameters. I will be going back to the locomotion unit in a month or so and sorting this problem is on the top of my to do list.

Let us know how it goes if you try the mod before this.

Tony

I am going to tackle this over the weekend hopefully. I will post the results of this attempt with photos hopefully of a working solution. Just waiting for the parts to arrive.

I am using a sketch for an arduino to be able to read the encoder for testing. There are a couple of uses for this...

1. Tell where I or Index is tripped - hook up I to pin 3 on the arduino I would suspect would accomplish this.
2. Tell the counts on an encoder/motor combo when you don't have the information
3. Tell if the encoder is working.
4. Tell if the flip flop circuit is working (should be 1/2 of what is reported without the flip flop circuit in line)

The output is sent to the serial port output of the arduino so it can be used with a computer to monitor. I figured I would need something pretty quick and easy to use for testing and it allows me to do the testing of the circuit on the test bed instead of in the robot.

starting code for arduino from things found on the internet. Because this is just something used for testing, I don't see the point in using much more than this at this point.

I did have to change encoder0Pos to be long instead of int because the encoder/motor combo exceeds ~32K counts per revolution.

/* Read Quadrature Encoder
  * Connect Encoder to Pins encoder0PinA, encoder0PinB, and +5V.
  *
  * Sketch by max wolf / www.meso.net
  * v. 0.1 - very basic functions - mw 20061220
  *
  */  


 int val; 
 int encoder0PinA = 3;
 int encoder0PinB = 4;
 long encoder0Pos = 0;
 int encoder0PinALast = LOW;
 int n = LOW;

 void setup() { 
   pinMode (encoder0PinA,INPUT);
   pinMode (encoder0PinB,INPUT);
   Serial.begin (9600);
 } 

 void loop() { 
   n = digitalRead(encoder0PinA);
   if ((encoder0PinALast == LOW) && (n == HIGH)) {
     if (digitalRead(encoder0PinB) == LOW) {
       encoder0Pos--;
     } else {
       encoder0Pos++;
     }
     Serial.print (encoder0Pos);
     Serial.print ("/");
   } 
   encoder0PinALast = n;
 } 

I have some doubts that the 4013 will be able to keep up with the encoders on these motors, but wont know until I give it a shot. If this works, it is definitely the cheaper option. The 4013 would run faster if powered with 12 volts, but then the output signal would also have to be reduced from 12v to 5v very quickly.

I also found encoders that are the same as the ones that come on these motors, only with 200 counters per rev instead of 500. The part number is HEDS-5505#E04. The E in this indicates the number of counters per rev. C D E or F will work. The shaft coming out of the back of the motor is 5/32in which is what the 04 fits. 06 is pretty common also, which is 1/4 but I don't know if this would work. The issue that I am finding is that 25 of these would need to be ordered in order for them to be purchased by the distributer.

if the HEDS-5505#F06 will fit, it looks like the best option for the higher torque motors because this would give you 256 counters per rev. The gearing in the higher torque motor is 1:127 so this would give you 32512 clicks per rev of the wheel, which would fall inside the 40K per wheel for the kangaroo. I just don't know if there would be any issue with this larger shaft size.

Fitting the 5/32 rear shaft through the encoder ring was very tight, so it might not be an issue. I figure if the 4013 circuit attempt doesn't work out, I will look at trying to use a HEDS-5505#F06 and see how it fits for the prototype I am working on.

HEDS-5500#C04 looks like the best option for something that could be shipped easily. I cant tell that the through hole option of the 5505 series would matter or not from the documents available. This would give you 12700 counts per rev, which is still really high. a 4 inch diameter wheel would be resolution down to .026mm.

Tough choices yes. I now use the arlo base in Cy since I learned how to slow the motors down some using the hb25s. Zagros base and motors are pretty good too.I'm now using them for a test design for a project I'm in the process of getting a patent for.

They are good motors for sure. I will check out the hb25's. This has been hanging out there for a while and I am finally to the point in my project that I need to do something about it, so, just trying to figure out the best option along with the most cost effective option. These motors are plenty strong for sure, and I like the speed for indoor use.

David, I am confused why you think a 4013 would not be able to keep up with the encoders? It is just a logic device (D-type flip-flop) and it can be clocked up to a max of around 16MHz (at 5v) which is way more than the requirement here for the /by2 needed to step down the encoder pulses. You are right, at higher voltages this max clock frequency would be even higher at around 30MHz at 12v but the 16MHz is already more than adequate for the application we have here. Be careful about running the 4013 at 12volts as the encoders are 5v and 12v pulses on the Roo would probably seriously damage it.

I agree with you, the best idea would be to change the encoders themselves (to 32512 clicks) if it all fits well with the motors then this additional 4013 circuitry would not be needed at all.

Thanks for giving us your feedback on this, as this is very useful information to folks making bigger robots that use the REX motors/encoders with the Kangaroo.

Tony