When do you expect to have the GHM-15 encoded motor back in stock?
Thanks,
-Nick T.
I do not have a promise date on those yet.
Where are the GHM-15 motors on the website?
Alan KM6VV
The Lynxmotion web site is like a great big Easter egg hunt!
Have you found the Blue SMiRF page yet?
-Nick K5YTO
More than likely it was removed because they can’t get a firm commitment from the manufacturer on either the product itself or delivery dates… or maybe there are not enough people chomping at the bit to warrant the costs of buying some minimum quantity. Last time I brought a product to market with some small Mabuchi motors in it there was a 20,000 pc minimum quantity buy. 
Oh and blue smirf is a sparkfun product. Other than tutorials to help folks figure out how to wire a popular bluetooth device to the Lynxmotion products why would they have anything but forum posts talking about it? 
Hi Nick,
No, I haven’t. Have you? I have read the tutorials on the Blue SMiRF. It would be nice to be able to search for anything. I looked for ages before finding the bearings I needed.
73,
Alan KM6VV
The search box only accesses product pages not the information pages. Unfortunately there’s nothing I can do about that. Because we do not sell the BlueSmirf it will not appear on the search results. We do have a couple of popular tutorials for using it with our SSC-32.
lynxmotion.com/images/html/build117.htm
lynxmotion.com/images/html/build125.htm
The site is very large so it may be difficult to find the information you are looking for. We do our best to arrange things in a logical arrangement. If anyone has trouble finding something on the website it’s as easy as a forum post or email to get help. I don’t mind taking blame for dropping the ball on something. But I don’t think Lynxmotion has done anything wrong here.
I did a search for bearing in the search box and got the three bearings we stock as the first three responses. We are always open to suggestions as to how we can improve the Lynxmotion website layout.
As EddieB has speculated we removed it from view until we get a firm commitment from the mfg. It will be resolved soon. I’m doing the best I can. 
That would be great. I don’t mean to pester you at all. I look forward to comparing the two servo motors and their encoders when they become available. I’m familiar with US Digital.
Alan KM6VV
Edit: Looks like now 3 motors are set up for an encoder. Although one of the details doesn’t show a tailshaft for the encoder. Which encoder(s) can be used? The thought occurred to me that it might be desirable to use one of the new 12-bit digital pots as an encoder. OK, it’s not an encoder, but you could probably use it for one. Might be expensive, 'tho.
I didn’t see where any of the motor controllers use the encoder, did I miss something?
Do any of the Atom boards take encoder inputs? Are there any build plans that use the encoder?
Thanks,
Alan KM6VV
it appears the motor controllers offered are open loop. so you would need to handle the encoders in a BA§ or other controller and adjust the PWM signal to the controllers accordingly. the outputs of the encoder are logic so any of the digital i/o ports on the atom should work. you might want to consider tying one of the phases to an interrupt, then use the other to determine direction when an interrupt occurs.
The Dimension Engineering guys are chomping at the bit to create a motor controller with encoder support. I’m sending them a rover with encoders ASAP. I think Solutions Cubed has some motor controllers that support encoders, but I have no experience with them.
I’m considering using the LMD18201 motor controller chip. I’ve used pairs of LMD18425 to control stepper motors in the past.
Microchip App Note 696a describes this with two PIC examples. The App note contains two nice C code examples of a PID controller with encoder inputs, one on an 18F452 in Microchip’s C compiler, and another one for the 16F877 in Hi-Tech C FREE “Student” compiler. Of course, I need it the other way 'round!
But these are single channel, but I need two channels! I might be able to modify their design to drive two motors, but it would be tough. I’ve used software FSMs to decode encoders in the past, but depending on the motor type, the spindle speed could be 6K! 100 CPS (not using quadrature) would make the job somewhat easier (10K pulse rate). I’d rather use a pair of counters in the PIC. Simplest solution would be a pair of 18-pin PICs.
The controller does acceleration/deceleration profiles as well. The output is anti-phase, where a 50% duty cycle is the “restâ€
The GHM-13 actually won’t work with the QME-01 encoder. Here are the only three motors that have the extended shaft to work with that encoder:
Thanks for catching that Beth!
I’ve been wondering exactly which motors would take the encoders.
Alan KM6VV