BeagleBone Blue – A complete, Linux-enabled robotics computer (opens in new tab)

It's open source, here's the PRU code: https://github.com/BelaPlatform/Bela/blob/master/pru_rtaudio...

This paper describes the platform in more detail: http://www.eecs.qmul.ac.uk/~andrewm/mcpherson_aes2015.pdf

This paper compares latency achievements using this strategy compared to Raspberry Pi, Arduino, Max/MSP, etc: https://qmro.qmul.ac.uk/xmlui/bitstream/handle/123456789/124...

Allwinner SoCs have an OpenRISC microcontroller used for managing deep sleep modes. [0]

I don't think anyone has figured out how to use it for other tasks yet, but it would be really great if there were more SoCs that included these kind of companion cores.

[0] http://linux-sunxi.org/AR100

This is something I plan to do once I get one of these beasts, although they're probably beyond my level of comprehension. Anyway, if they can be used to synthesize signals at very high speed, what about using them to build a DVB-T transmitter? When TV went digital we lost the ability to send a signal to a TV using an extremely cheap modulator, and last time I checked the only units around are priced several hundred quids, so if doable an application like that one could be truly interesting.

I've been looking at boards for days now trying to find the perfect one to suit my needs and this is exactly what I've been looking for. I've seen the beagleboard before but I never noticed this feature before. I'm glad I saw this post this morning!

The story of why this world of "linux" machines is a disaster in seven words. I'm sure this new BeagleBone is just a tarball flinger too.

I ended up going Navio2 and haven't looked back. Also the RPI3 is powerful enough to run list ROS tasks.

Having used them I loved them, but they aren't a tool I reach for at first. But now that you've brought them up I kind of want to use them for something.

But why this board has RC PWM Servo ports? Because it's a cheap easy way of interfacing with things. More importantly, it let's you hook Brushed/Brushless ESCs up fairly easily to get things moving with motors that draw more than 1 amp.

1) DC Brushed - Spark ESC https://www.amazon.com/SPARK-Motor-Controller-REV-Robotics/d... (Disclaimer - I know the owner of Rev, he's a friend) 2) This is really a function of scale more than anything. But yes, they are expensive. 3) With the advent of 3d printing it's at least manageable to put something around them

But I agree with you that most of these are incredibly annoying.

Look at something like an AX12W dynamixel which costs $25 more than an equivalent Futuba S3003, roughly same torque and speed. Given the control capabilities of the AX12 I don't see the point of buying the Futuba product.

Or a Futaba S9452 is about $90 for 130 oz-in of torque or Dynamixel AX-18A for $95 for 255 oz-in torque. Eh an extra $5 for twice the torque, not that ridiculous.

There obvious scaling problems where putting a vary fancy controller on piece of junk mechanicals doesn't make economic sense so you'll probably never see something with the control features of a dynamixel on sale for $5 each.

[1] http://www.trossenrobotics.com/dynamixel-xl-320-robot-actuat...

There are more than a few h-bridge ICs out there that can easily control many amps of current; Infineon's BTN89xxx line is fairly popular, but there are others. Many can be found as "breakout boards" on Ebay and other places. They'll usually control 12-24vdc @ 40A and more; they are MOSFET devices (n-channel, integrated high-side pumps, etc). These boards are fairly cheap.

Now, an h-bridge of course doesn't make a motor controller, but it is the most difficult piece of the puzzle, and perhaps the most expensive part (in terms of electronics hardware and developing one - because frying MOSFETs or IGBTs in the process of development can add up quickly). The rest is monitoring and code (basically using a microcontroller to interpret control signals and feedback signals from current, encoders, etc - implement PID as needed for speed or other control, overcurrent monitoring, etc).

Of course, none of this will match the capabilities of a Roboteq or Vantec motor controller - but you won't be spending several hundred dollars, either. These lower end devices and designs (and there are other companies that make lower-end controllers, like Dimension Engineering and others) are more than enough though to control electric wheelchair motors (but if you want proven "bulletproof" controllers, spend the money).

And if you are really cheap or want to experiment? Pick up some cheap logic-level high-amperage N-channel mosfets off ebay (or other places), parallel them together for more current handling (of course, there may be issues with capacitance load), then build a simple "h-bridge" from 40A Bosch relays scavenged from a pick-ur-part (most of those places give 'em away), and put the mosfet pack on the low-side connected to ground. A couple more mosfets to control the relay switching, and you have a (somewhat) cheap (though large) 40A PWM-capable hybrid h-bridge (just don't switch the relays while PWM'ing!).

I guess all of this is to say that there are plenty of inexpensive options out there that aren't "old-school" L293 or L298 solutions (though honestly, for their application, such h-bridge controllers still work well, provided you pair them properly - that is, larger motors running at 12 volts or a tad more off of gel-cell or similar batteries, when efficiency isn't as great a deal).

But good for me because I paused shopping to vent here and I realized I may actually not need it that badly having enough MCUs at home already.

Then you have incompetent vendors like Olimex, Pine64, Next Thing Co (of C.H.I.P., the "$9" SBC) that fuck up the hardware, software, or both, and forget critical stuff like heat spreading copper layers in the SBC (Olimex), misroute ethernet so it can't actually do a gigabit a sec (Pine64), or lie about SOC software support and scramble to port the closed blobs that make their board work forward (Next Thing Co).

$60/quarter was what you asked for, interestingly.

third one ships this week or so.

I'm not sure if its an upside or a downside that all the boards are adafruit products. Its adafruit so its excellently documented but its essentially the "feather ecosystem quarterly subscription" in practice. I realize they have customer service type costs but it would be interesting to see something other than feather ecosystem products. I'm not saying its not fun, its a lot of fun, I'm just saying it would be more fun to get something truly weird in the box.

I enjoyed building the robot in the second box and generally hacking around on it.

In practice, you can use the A8 as if the PRU is not there for 99% of what you want to do. You can also get into programming the PRU itself, but this is very much for the advanced user.

BTW, I don't see the PRU referred to anywhere else as "Cortex-M3".

https://www.element14.com/community/community/designcenter/s...

https://e2e.ti.com/support/arm/sitara_arm/f/791/t/284956

http://arago-project.org/git/projects/?p=am33x-cm3.git;a=sum...

http://www.ti.com/lit/ug/spruh73o/spruh73o.pdf page 1172

Looks like it works right out of the box with ardupilot's git head

For the projects where you would benefit from a GPU, you could perhaps commicate with a bigger computer that does the calculations? Too much latency for some applications of course but not for others.

If your project really needs a GPU and it needs it on the device that is controlling the robotics components, I think probably something other than the BB Blue would be more appropriate.

Wat. I know this is hacker news, but not every project requires a DNN.

I use a BB Black in an outdoor location and it runs 24/7 with no hitches, and has been for months. It's in San Francisco and it's inside a control box, so not the most extreme conditions, but it has survived all the recent wet weather and hot days last summer with aplomb.

edit: I have flashed the firmware numerous times on several boards and have never had an issue.

They're a little weird about joining before access is granted to see the goodies and get involved in the group buys and so forth. I've been meaning to get started on a styrene laser cut but... life, infinite number of things to do, its warming up outside so I'm more motivated to daydream about my electric bicycle conversion plans so maybe next winter, etc.

I don't see the point in spending $600 for anything but a 1:1 scale model, and conveniently you're looking at "high three figures" for styrene unlike the $2K or so for all aluminum. Also a lot of cost depends on insistence on perfection delivered today vs "ah I'll put that detail on next winter" attitude. There's a big cost difference between "I'm building a droid that looks like its in the R2 family from 50 ft away" vs "I am making a droid that is so good that it could be used in a hollywood movie as a prop if not main character"