Recycled parts for my CNC

I am all about reusing,  recycling junk in my builds.  The cutter/spindle motor is no exception.   I've been shopping around for my spindle motor for my cnc.  Estimated this would cost me $70-$150 for this part alone.  Then while looking for some hardware in my junk box,  I came across the perfect motor! 

This is a Ryobi SS180 speed saw/circle cutter that I purchased as part of a Ryobi tool package almost 10 years ago and has never been used.  I cracked it open and found the perfect spindle for my cnc.  Perfect especially since it is FREE! 

The motor is rated at 26,000 @ 18v dc.  I can hook this up to the cnc controller or more likely,  I will connect it to it's own DC PWM controller for manual speed control.  It has a 1/8" and 1/4" reversable collet sleeve already on the shaft as well as a high speed bearing.  It appears the shaft is hardened tool steel,  so it should work  very well.  Also is air cooled (fan). 

 Mounting threaded screw holes on the body and the beefy 32mm bearing on the shaft will make mounting extremely easy. Never know when you will be able to use something in your junk drawers!

  Another new addition to my shop is a Grizzly G8750 compound slide table for my drill press!  Until now I have been doing all my metal machining freehand.  I wish I had this when I started my build.  It makes everything so much easier and precise! Next upgrade will be a new drill press.

Bearing and motor mounts in t6061 aluminum are so much more precise with the X-Y compound table!  It's a dream! 

Lawnbot's off road test drive video!

 Here is an updated video of the actual lawnbot running on the lawn.  (water rationing in southern Calif.  So not much actual lawn!)
 Initially it kept stalling out a couple times a minute.  Pause for just a second.  I thought it was pulling to many amps and the code was shutting the circuit down for safety.  This was not the case.  It was actually reading the radio to soon and was dropping packets.  This result in a no connection result that put the code into a loop till it received valid data from the transmitter.
  I did find that the current readings were topping out at 10amps (each motor)  with a quick change of directions.  So I installed the - 30 to +30amp current sensors and have them safety checking at about 15-17amps. I'll check after the added weight of the propane motor and it's electric starter motor,  to adjust it any further.  Right now the pwm is limited to 90 out of a possible 255, so there is still a lot of performance possible in this build!
  In the video,  you will notice that it manages to drive up and over the border bricks.  This was a surprise since I didn't think it had that kind of torque/power.  Still quite a bit of fun left in all these recycled scraps!
  Motor mounts for the propane motor and it's custom starter motor are next on the list (after weight/amp tests).  So be sure to check back.  Any questions,  please let me know!

Brains behind Arduino Lawn Mower!

Finally got a delivery from China.  It is the new Arduino Mega 2560 R3 compatible MCU along with a the v2 Sensor Shield.  (this combination had the same pin to usb short I discussed in an earlier post.  Be sure to check that post for the fix or it will fry your mega 2560! (Arduino Mega 2560 shorts against v2 Sensor Shield)

 It took a couple weeks to be delivered,  but the price is less than a quarter of what the cheapest price vendors are offering it here in the U. S..  Not only do a lot of local vendors order them from china,  but a lot of auction sellers will take your money and have it drop shipped from china.  Well worth it to do some research and cut out the middle-man! 

Now that I started to put the components into the battery box,  it is getting very tight with the new SLA 12Ah 12v battery.  The solution is to build a multi-level control board that will slip right in beside the battery. Seems like it works very well,  but it might get a little tight after I start adding sensors and more wiring. 

Hobby RC remote for testing the Lawnbot!

I've been stuck indoors, unable to work on the mechanical parts of our robotic lawn mower.  I took advantage of this time and wired a Futaba FP-R127DF 7 channel Receiver to an Arduino Uno r3 and wrote a few lines of code to see if I could get it to read the signal from a Futaba T6XH-Super PCM1024 6 channel transmitter.  Was a lot easier to get the Arduino to display the signals than it is going to be for me to figure out what they all are.  This is a programmable aircraft/helicopter remote with settings for just about everything.  Ailerons, flap, Swash Plates and mixing of all the signals.  Wish it was a standard RC car remote!  It's going to take some research to program the transmitter.  With what I do know now, I believe I can get it driving the bot. 

 I started out the day knowing nothing about how to read or interpret rc hobby remotes.  I searched and found a real nice tutorial over at sparkfun.  Wasn't as complete as I thought,  but there is additional info in the comments that will help get it working with dual motor controllers.  The actual page is: https://www.sparkfun.com/tutorials/348

 BTW, not sure if the Raspberry Pi running Raspbian allows for enough time slicing in the multi-tasking to be able to poll the serial ports (usb)  for an rc transmitter combo.  I originally started using the Pi to program the Arduino as I always do.  When I opened the serial port monitor to view the signals, the cpu bogged down and brought the entire system to an absolute crawl at 9600bps.  Made it unusable.  Was forced to bring out another machine with an OS that I loathe! If it weren't my kids, I would install linux on it.  If you were to really delay the polling, you may be able to read it, but I would really check into other OSs or distributions if you want to use it with the Pi.  This is one of the reasons I  will be using the arduino with the Pi on this robot. 

 Tomorrow I hope to post some new updates on the chassis.  At the latest I hope to have something actually moving my the end of next week!  

 I also updated the current hardware page.  This is really starting to run together.  I think it's time to separate the parts by project.  That way if you are trying to duplicate something,  you will know exactly what I  did it with. 

Repair Terminals on Hobby DC Motors.

A lot of people think the motor is destroyed when the fragile brass terminal connector that connects the wire to the motor's brush tears off. It happens all the time from wear and tear or even from disconnecting a terminal plug when they are brand spanking new.  Most times there aren't replacements available for a darn good motor that has years of service ahead of it.
  Here is a quick and dirty fix which is not only a temporary fix, but could be way more secure than the original tab ever was.  First, most often it breaks off at the motor frame and there is no metal to solder anything to. If you are lucky, you have a small gap wide enough to insert a couple strands of thin (stripped 24 gauge or smaller) solid copper wire.  But most there will be no way to clean the existing metal.  Lets change that! (If you can get away without drilling, don't drill! If you get to aggressive, it can destroy the brush terminal!) Take the smallest drill bit you can find, most often that will be 1/16th of an inch. If possible, go even smaller with specialty bits.  We're not drilling through the case, so take it slow with a hand drill or drill press.  I used a hand driven twist drill since you just want to open up/clean the area beside the motor's connector enough for a couple pieces of thin copper wire.
You want to drill straight down beside the existing brush/terminal connection. A power drill will drill a hole too quick and chew the brass brush to bits. I fit 4 small pieces of solid strand copper wire beside the broken brass terminal. Then solder the brass and copper together making a new solid tab. That's it.  Test your motor and you are good to go!

This motor required that both terminals be repaired. Works as good as new!

If you notice the circuit board in the upper photo with 8 mosfet and close to 30 transistors. Our new dual 45 amp motor controller for the upcoming robot! Lots of good stuff coming, stayed tuned!