tf_archiv

The machine is build out of aluminium profiles from MayTec: http://www.maytec.org/mainframe_e.htm There are unfortunately no construction plans or the like. Also the profiles are quite expensive, the materials we used are probably more expensive then a ready-to-use beginner CNC mill. And just as a disclaimer: If you want to use Stepper Bricks to control a CNC machine, you have to put in quite a bit of work. You either have to write your own gcode parser that translates gcode to commands for the Stepper Brick or you have to adapt something like Linux EMC. A second solution i can think of is to use 3 Stepper Bricks with 3 Debug Bricks and to write a small C firmware that sends the serial commands to the driver IC on the Brick. This way you can use Linux EMC as it is. The third and definitely best solution would be to write a C firmware for the Stepper Bricks that can parse gcode directly. This could beat every hobby CNC mill out there that uses Linux EMC in terms of precision. But this would also be lots of work :-).

i was thinking it might do well as a 3d printer/ mill combo

I agree. I would love to see how you built this.

in your introduction video you had a desktop mill. Is the plans for that thing on the internet any where?

I think you need to connect the Switch to the IO Bricklet. Then you should be able to calibrate the stepper when the switch is pushed. Not sure though, since i'm new to all this.

Hi! Typically you connect a switch to an IO Bricklet by connecting one pin with the logic pin (A0...A7, or B0...B7 in case of IO16) and the other pin to GND. When you enable the internal pullups of the IO Bricklet, all pins are logical "high". If you now press the switch, it will short the logic pin to GND and your pin gets logical "low". Hint: Its important that you switch the internal pullups. If you do not, the signal is floating when the switch is not pressed and you get random behaviour. I hope thats helps. Cheers, Bastian

Hi I want to use the Stepper Brick to control something similar to a conveyer belt but I need to be able to "reset" the position to a known position after a full action has been taken. You can compare it to the calibration a printer does from time to time to verify that the printer head is at the right position. Can I use the Micro Switch to do this and if so, how do I connect the Switch to the Master Brick/Stepper Brick? /A

Hi! We want to offer a Wlan Master-Extension, such that you can use it without Brick Deamon. The web server functionality is a nice idea, but I think that we can't offer it directly when the WLAN Extension will be available. Cheers, Bastian

+2 any added network connectivity would be SO incredibly useful in ways of in-home automation!

+1 In the German section is this as a Lan Brick already on a wish list. Even the control via web browser.

Will there be a Wlan brick with perhaps a small web server functionality for a direct web browser for viewing/controlling?

Depending on your system (how you connect Bricks/Bricklets) you can reach 1ms latency with our system. Cheers, Bastian

Just to share some experience on robotics contest. To create robot for eurobot, i need most of the time Analog input (this enable the use of variable resistor as precise sensor, but also enable the use of numerical hysteresis and/or debouncing, reducing a lot analog part), for output i need most of the time PWM, for DC motor using a single transitor (hexfet are nice with a tension of transistion fixe around 1V), for servo, or 2 for DC motor using h bridge, then 3 for use of brushless motor (but i never tried). Then if you want a "reactive" robot, a 1ms latency is the way to go, it's faster than mecanical latency but it's a way to have precise feedback beavior. This latency is time taken by the system from input to ouput.

I can only agree. Really great idea. Great Project. Well realized. I hope you will expand soon. I think the more successful they are, the longer they will need for the rpm packages. :-D But they provide the source code. There are many Manuals and HowTos in the web which explain to create a rpm package based on source code. So, like first aid, your yould create your rpm package on your own. Yes...ok, it ist not as easy as waiting for their package ;-)

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Thank you for your kind comment. I think we have to prepare a description how you can connect stepper motors to the Stepper Brick. But currently we have got our hands full to prepare the shipping of the orders and fixing some problems with our site. Please be patient. Cheers, Bastian

Your stepper motor brick controller has 4 wires from the diagrams. Is it possible to control 5 or 6 wire stepper motors with this brick? Could you describe how it might be done if so please? Brilliant site and I have huge hopes for your success in the future. I am only a beginner in this field but the clarity of the site has really inspired me to tackle this. I do hope you make an easy to use approach to upload code to the modules so they can become autonomous.

could you not do brushless with the 7 servo driver brick. 1 DC esc 3phase , per brushless . some esc's have a feed back wire, and take servo pwm . you can read the feed back pulses on a bricklet? or possibly use a he sensor near the drum(s) if you use real cheap ones . only asking. Sry, i just love micro and mini brushless. once you tach em , kv rating lets you ajust rpm via voltage from there? i fly rc with thrust diferential for yaw , just 2x 5g brushless , and 2x 6a 2s rated esc , powerd by 2s lipo , you just need to pull v+ pin off the esc , as most have bec's in them. the V level on the main dc input relates directly to the kv rating , once you tach it to calibrate . maybe not accurate enough for you to just aproximate by V+ supply at esc.

We have a encoder-bricklet in preparation. It is planned to extend the API of all driver Bricks such that they can control the rounds per minutes of the connected motor directly. The speed you can interchange messages depends on the way you have connected the bricks and bricklets. If you build a large stack, the number of messages per second for each brick in the stack gets less, compared to a system in which you have connected each brick seperatly to your PC over USB. Cheers, Bastian

In robotic, you could have many IOs. If you use getter for each IO, you have a round trip for each. In general, you have a main loop, where you want all data at the begining and set the output at the end. So you can have a protocole where all data are send in rythme, you avoid the round trip, this halve the latency and saves a lot of bandwith. You can even masqued the IO: you receive the n+1 data group, when the group n is computed, and the result n-1 send back to the slaves. PC are not very good for low latency. It's easier to have a master mcu, and use the PC has slave for computer hungry task. To control a simple tank design robot, you will need 2 encoders-bricklet, 2 DC bricks, why not having a more complexe bricks that handle 2 DC motors (or even bruchless one) with feedback ? Maybe you could also provide the feedback loop for 2 axis (which is not easy at all).

First of all: The Number of messages you can send to Bricks solely depends on the implementation of the USB stack from the operating system you use. The Bricks themself could handle 100khz and more. I just made this small test on my PC (linux 3.0.0-13): http://pastebin.com/NrKmWhn6 The output was 9.4246690273. Which means the roundtrip time (a message is send from your program to the Brick Daemon, over USB to the Brick, the Brick answers to the Brick Daemon and it sends the answer back to your program) takes about 1ms. This means your feedback loop over USB is perhaps possible if you only use one Brick. If you have a Stack of Bricks with many connected Bricklets, they all have to share the same USB connection. Over a wireless connection such a feedback loop is definitely not possible. The latency is just too high. But, as Bastian already said, we intend to release an Encoder Bricklet that would solve your problem.

How could i do feedback motor control ? Usually a encoder wheels are used or a magnetic one or even for single rotation, a variable resistor (intensity feedback is too slow). For fast reaction, the frequency of the feedback must be around 1khz, is it possible using our stackable design ?

We have a big list of other languages we want to support and you should be able to use the C bindings in Objective C. I don't think there will be direct Objective C bindings anytime soon.

Is there planned support for other programming languages, like Objective C?

Hello Olaf, Thanks for the reply, this helps a lot. I'll order some elements shortly. Kind regards