View Full Version : Question on controlling HB-25 using Propeller

03-15-2012, 04:10 PM
Hi everyone, I'm facing a problem with having the HB-25 to run using Propeller. before posting this, I had read this post:


I (http://forums.parallax.com/showthread.php?91535-what-up-hb-25&p=628399#post628399) tried the code, it din't work. I did my own code which I will attach here as well. Apparently, the propeller can perform Pulsout to the HB-25, but it did not respond to it. I tried to plug in a standard servo to another set of pin and the servo did run. Any idea on what will be the possible cause of this?

More information if you need: I'm using a propeller USB Protoboard, powered with a 9v battery. The same goes to HB-25. The HB-25 is connected to the propeller on pin 7, correct connection/polarity.

Appreciate any help provided :D

03-15-2012, 05:24 PM
What kind of 9V battery are you using and what kind of motor is connected? If you are just using a small 9V transistor battery then it may not be able to supply enough power. Once of the first things I would do is try a separate battery for the HB-25's.

The HB-25's should respond just like a standard servo.


03-15-2012, 07:44 PM
I agree the problem will be the 9v battery. Motors can take a lot of current to begin moving.

The HB25s can handle something crazy like 20 Amps. I regularly use mine with a 12v sealed lead acid battery,controlling them is as RobotWorkshop says, just like a normal servo.

Duane Degn
03-15-2012, 08:21 PM
If you're using a different power source for your Propeller, you'll want to make sure the two power sources share a common ground.

03-16-2012, 01:41 AM
Yea those 9v transistor battery plus a tamiya motor. I will try with other type of batteries in lab tomorrow and report the result here. Thanks for your help guys :)

Beau Schwabe
03-16-2012, 03:56 AM
As a wise man once said to me when I got my first HB-25 and was having similar problems running it off of a 9V battery.... "Dude, your trying to start a car with a watch battery" ... well he didn't say it exactly like that but it was the same point he was trying to make. <- Thanks Chris Savage :-)

A 9V battery definitely does not supply enough current for the HB-25 ... You need something with a few Amps behind the wheel for the HB-25 to operate correctly.