Why start with a BBB/Pi4 and then add a screen and so on. A better starting place would be a low-cost Android tablet. Perhaps like this one. For $120 you get the CPU (that runs Linux), a touch screen and WiFi. What is needed is a way to connect it to a machine tool. https://www.bestbuy.com/site/samsung-galaxy-tab-a7-lite-8-7-32gb-with-wi-fi-dark-gray/6464584.p?skuId=6464584 Samsung Galaxy Tab A7 Lite 8.7" 32GB with Wi-Fi Dark Gray SM-T220NZAAXAR bestbuy.com
I would use something like a small 32-bit micro controller to do the real-time pulses and switch monitoring. If you would choose an ESP32 then the interface to the tablet is wireless. But you could use USB as both devices have USB built-in. USB has a built-in asocronus mode where data moves in strict real-time. But this might not be needed if 100% of the RT loops are onthe microcontroller. The ESP32 is a dual-CPU, 32-bit device with more then enough computer power to run a CNC controller. I would 100%, for sure run an RTOS (FreeRTOS or Mbed) on the ESP32. The tablet is just the user interface and “MPG”. I am currently using ESP32 to generate PWM control for a 12-axis robot and I’m getting sub microsecond pulse accuracy which is more then my application needs. It is very fast and written 100% in Python. If the user already had an Android tablet or wanted to buy a used tablet you really could under cut the cost of a $500 Chinese device. LCNC was written to take advantage of “cheap” community hardware. This is when a basic 16-bit PC would sell for “only” about $3,500. Today’s commodity hardware is called a “cell phone” and they are MUCH more powerful then the old PC was. > On Aug 5, 2023, at 3:23 PM, John Dammeyer <jo...@autoartisans.com> wrote: > > Me too. A closer look at the fine print and selecting the correct button > shows the actual CNC controller is $513 or $541 for 3 or 4 axis respectively. > The MPG is priced separately at $96. > > And this is why a BBB with a cape that included a Break Out Board with a few > relays etc. for under $100 would be quite the bargain. The question is then > what sort of display would be good. And you still need some sort of MPG to > go with it for also about $100. > > For $94 I can get, from amazon.ca a 7inch HDMI LCD (H) 1024x600 Monitor IPS > Screen Capacitive Touch Display Supports Raspberry Pi Jetson Nano BeagleBone > Black Banana Pi & Microsoft XBOX360, Sony PS4,Nintendo Switch > > And therein lies the problem. Creating something similar to the $500 Chinese > CNC controllers with touch screen will ultimately cost in the same $500 > range. But unless the MachineKit or LinuxCNC version is stable with a target > life similar to the life of the machine tool no one will spend the energy and > time to make that. > > The market isn't big enough to justify the work required. Which is why so > many of the Beagle Capes are no longer available. Next week there's an new > ESP32 with more bells and whistles. Won't do what the Beagle does but ... > > John > > >> -----Original Message----- >> From: Martin Dobbins [mailto:tu...@hotmail.com] >> Sent: August 5, 2023 11:44 AM >> To: Enhanced Machine Controller (EMC) >> Subject: Re: [Emc-users] Beaglebone black latency >> >> It makes me wonder which operating system they put on that Chinese >> controller, and what motion control system. >> >> Martin >> >> ________________________________ >> From: John Dammeyer >> Sent: Friday, August 4, 2023 7:41 PM >> To: 'Enhanced Machine Controller (EMC)' <emc- >> us...@lists.sourceforge.net> >> Subject: Re: [Emc-users] Beaglebone black latency >> >> My biggest issue with the Xylotex BBB Cape for CNC was that the logic for >> ESTOP was inverted. ESTOP was a N/O switch so if a wire was broken you >> wouldn't find out until you tried to save a body part from being injured with >> the ESTOP. > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
