Buy an Axon, Axon II, or Axon Mote and build a great robot, while helping to support SoR.
0 Members and 1 Guest are viewing this topic.
I also have the actual wheel graphic taken care of, my problem is the physical mounting of the disc.
I think that I will try layering some paper discs with krazy glue to get a better thickness/stiffness then put a hole in it and use some more krazy glue to hold it onto the shaft. Wish me luck in not gluing the rotors in place .
What diameter is the disc?And how long is the 1mm axle?
The discs I'm currently working with are slightly less than 1 cm in diameter.The axle is ~4.5 mm.
[...] suggestion about the spur gear sounds the most promising.
Appreciate the input on the sensor, this is the first time I've used these but they are working as I hoped. I was planning on running the encoder lines through a comparator against a reference voltage to clean up the signal in the final design but I'm reading logic level changes already without that.
Any plastic or aluminum disc of 3mm to 4mm thickness should do with this small diameter and one of your local machine shops, auto repair shop or similar will have a drill press and perhaps a kind soul willing to drill a few holes for you.Have an eye out for useable parts when shopping - you might find just the right piece among toys, kitchen utensils or in your local hardware store (complete with helpful shop clerks, if you go there in the quiet hours)
Test it in different types of light. Fluorescence lightning can interfere (as well as direct sunshine). Shade the sensors if light gives marginal readings.
If you see problems that isn't caused by having the segments of the disc too close for a well defined on/off signal, you can let the reference voltage always be half the amplitude of the resulting signal. A little hysteresis will help as well.
I was actually just going to test in one kind of lighting then get the whole assembly boxed up. I figure that's one of the advantages of having the encoders on the non-ouput side.
If I understand you correctly here, that's what the current test set up looks like, my logic is running at 5V and I'm using 2.5 for the reference.
I've got a quad op-amp sitting in front of me and I'm trying to wrap my head around schmitt triggers.
A clothes button may do as well (just drill the center hole a wee bit tight)
I ended up doing this and it works great, thanks for the advice.
The encoders are not working reliably yet but I'm pretty sure it is because I don't have the enclosure over them yet.
Perhaps use less segments.
Edit: Success, everything seems to be working, the speeds reported by the encoders both correspond with what I can observe with a stopwatch and match each other to within about 1% when running at 100% duty cycle which is one of the reasons I started down this road in the first place.