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Vin pin on Brain Shield
06-27-2016, 12:59 PM (This post was last modified: 06-27-2016 01:57 PM by rosbot.)
Post: #1
Vin pin on Brain Shield
Hi,

I'm asking for Vin pins on Brain Shield. What are they?

Hoe can they be used?

thank in advance

I'm asking this because I would like to use 17hs4401 nema17 motors but they works at 12V. I''ve seen using Leonardo voltage motor doesn't work properly.

I'm trying to use a direct line from external source (8xAA battery) so I can power motors directly at 12V.

From schema I've seen Vin+ is directly connected to A4988 positive power supply so can be used to power motor drivers.

I'm right?

Looking also on Leonardo sch Vin and jack power supply are connected and described like External power.

This means Vin is already at 12V and A4988 are already powered with it.
I'm right?

If true, Why motors doesn't works?
I tuned Vref on A4988 but there is only noise. Another point is that one motor works much more the other.
Any suggestion?
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06-28-2016, 04:32 AM (This post was last modified: 06-28-2016 04:33 AM by Ing. Lucian.)
Post: #2
RE: Vin pin on Brain Shield
(06-27-2016 12:59 PM)rosbot Wrote:  Hi,

I'm asking for Vin pins on Brain Shield. What are they?

Hoe can they be used?

thank in advance

I'm asking this because I would like to use 17hs4401 nema17 motors but they works at 12V. I''ve seen using Leonardo voltage motor doesn't work properly.

I'm trying to use a direct line from external source (8xAA battery) so I can power motors directly at 12V.

From schema I've seen Vin+ is directly connected to A4988 positive power supply so can be used to power motor drivers.

I'm right?

Looking also on Leonardo sch Vin and jack power supply are connected and described like External power.

This means Vin is already at 12V and A4988 are already powered with it.
I'm right?

If true, Why motors doesn't works?
I tuned Vref on A4988 but there is only noise. Another point is that one motor works much more the other.
Any suggestion?

look here: http://forumsjjrobots.com/thread-7.html

is the electrical diagram, you see that the 12v are those who feed the arduino, a4988, the entire circuit has its 5v voltage regulators and 3.3V, if you only work a motor, check the connections, can be fake.

...Google translator
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06-28-2016, 09:57 AM
Post: #3
RE: Vin pin on Brain Shield
Hi,

I already see the brd and sch file. I suppose it's the old version because servo and sensor are located in a different position.

My Brain shield ha servo 1 & 2 near Vin pins and I2C between first A4988 and wifi module.

In brd file you posted (feb 2015) layout is quite different. here you are the board I found.

.bmp  BrobotShield.bmp (Size: 341.61 KB / Downloads: 51)
Can someone share last layout?

Thanks
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06-29-2016, 09:18 PM
Post: #4
RE: Vin pin on Brain Shield
(06-28-2016 09:57 AM)rosbot Wrote:  Hi,

I already see the brd and sch file. I suppose it's the old version because servo and sensor are located in a different position.

My Brain shield ha servo 1 & 2 near Vin pins and I2C between first A4988 and wifi module.

In brd file you posted (feb 2015) layout is quite different. here you are the board I found.

Can someone share last layout?

Thanks

this is the most current version of the brain, there is a pdf file within the circuit
...Google Traductor


Attached File(s)
.zip  Brobot ESP12.zip (Size: 103.94 KB / Downloads: 48)
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06-30-2016, 06:57 AM (This post was last modified: 06-30-2016 07:25 AM by rosbot.)
Post: #5
RE: Vin pin on Brain Shield
Hi,

This is version of my board. Thanks.

I bought only the shield so I had to do some soldering work (pins) on it. I applyed pins I suppose needed but I'm not sure because there are no info on my shipping package on how to solder all.

May be I missed some jumper or some other thinks I need to have a complete working shield.
There is any instructions or guide on how to solder and complete Brain shiled for people that take it separately? or at least some picture of both shield sides so I can view if I miss some work to do on it?

This because I still have problem on motors. They do noise. Only if I put BRobot in my hands wheels are free to move. I see wheels rotations and they change spin direction following BRobot inclination (or at least seems so). If I put BRobot on the floor I listen only noise.

I checked again Vref on my Nema17 (I used it with A4988 drivers on my 3D printer and work perfectly) and also Vcc is already at about 12V so I suppose there isn't any power problem.
Probably remains some jumper missing (for microstepping) or some other jumper because I see there lots of hole in board free and I don't know if I must solder pins on it and ho to cable it.

Just another question. When I switch on BRobot, I must leave it in horizontal position (and BRobot stand up itself) or I must find a vertical position to complete starting autocalibration?

Thanks in advance

Rosario

Hi,

I found a picture on jjrobots.com with Brain Shield clearly visible.

There are no other pins to solder so seems I've done all jobs needed.

I ordered a set of 42BYGHW609 so all parts are compliant to your BOM. I hope this may solve issue.

I'll inform as set arrive.

Thanks
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07-01-2016, 08:56 AM (This post was last modified: 07-01-2016 08:57 AM by rosbot.)
Post: #6
RE: Vin pin on Brain Shield
Hi,

seems I solved some problem. Now my BRobot go. Not so good but go. I changed power with a NiMH battery with 7.2V with still 17HS4401 motors.

I observed there is some problem with gyroscope connections so I build a new cable to connect MPU6050 with Brain Shield.

After that magically worked !!! ;-)

There is still a problem with motors. There is noise but not at all time. Only in some cases. I've seen that if battery goed down noise is always present.

So I suppose depends on 7.2V (17HS4401 works at 12V). I'm waiting new motors so I can check if this is reaaly the problem.

At the moment, I'm able to play with my BRobot using Google app. Is a bit instable due to battery position (is larger than Brobot so I had to put it on top of BRobot).

I'm designing new horizontal parts of BRobot to be able to put battery between motors and arduino so all is more stable.

I'll inform you when all is done :-)
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07-03-2016, 06:18 PM
Post: #7
RE: Vin pin on Brain Shield
(07-01-2016 08:56 AM)rosbot Wrote:  ...
I changed power with a NiMH battery with 7.2V with still 17HS4401 motors.
...
7.2V is very low for a4988 driver. It can be unstable because it need 8-35V according to datasheet
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07-13-2016, 05:59 PM (This post was last modified: 07-13-2016 06:06 PM by rosbot.)
Post: #8
RE: Vin pin on Brain Shield
Hi, I'm using BRobot since a week and I'm happy with it.

Finally I used properly the jjrobots app and now I can drive it fine. Sometimes There is still some noise but I just put Bot horizontally and noise go off.

There is still the problem with motor. The ones I ordered was shipped so I need to find time for mount them.

I'm waiting also for a new 11,1V LiPo Battery (6000mah) so I can resolve all my issue. I suppose I need to wait at least 3 or 4 weeks.

I also designed new 3D parts to accomodate 13,5cm battery size (at the moment I locked my battery at the top of Bot causing instability).

I'll share soon all parts. At the moment I'm printing them and I need to test them if all is ok.

See you soon.

Thanks for your support.
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