Trinket Rover

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scottw10
 
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Trinket Rover

Post by scottw10 »

I am a middle school special education teacher developing a curriculum for a STEM/Robotics club at our school. To this end I've acquired several mini-sumo robts, boe-bots, activity bots and some line followers, but I want to start with a real hook. I found the Rover project really intriguing and want to build several of these as way to get the kids fired up in the beginning. (I've read about the need to adjust the Arduino IDE.) But I have a few questions:
1) You sell the Tower Pro micro servo but the project shows the Turnigy servo with no link to the Tower Pro. Any reason for this? Also, how about the Fitec continous rotation servo <http://www.robotshop.com/en/9g-continuo ... servo.html> to avoid the continuous rotation hack?
2) The Rover project really got be excited about 3d printing and I think designing and printing robot parts will be a great addition to the curriculum. I know you sell MakerBot printers, but they are out of my price range. Do you have any compelling recommendation for a sub-$1k printer? Solidoodle? Cube? Printrbot?
Many thanks for the Adafruit educational materials. 8)

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adafruit_support_bill
 
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Re: Trinket Rover

Post by adafruit_support_bill »

The budget servos such as Tower Pro, and Turnigy are all pretty much interchangeable. The Fitec CR servo should work fine in this application as well.
There were a bunch of sub-$1K 3D printers announced at CES recently. I'll check with our 3D printing expert to see if he has any specific recommendations.

matt_adafruit
 

Re: Trinket Rover

Post by matt_adafruit »

Hello Scottw10,

While we don't offer other 3D printers yet in our store, we suggest that you take a look at the MAKE Ultimate 3D printing guide for a few suggestions. There are a number of units in your price range, including the excellent Printrbot Simple, and each has its own strengths and weaknesses for you to consider.

As you start to create 3D printed robotics projects, please remember to drop us messages at [email protected] with links to projects that you and your students create and share online!

Thanks,
Matt

scottw10
 
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Re: Trinket Rover

Post by scottw10 »

thanks to Matt & Bill for the advice. We'll keep you posted as our project moves along.

scottw10
 
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Re: Trinket Rover

Post by scottw10 »

Hello-
I have learned that a high school in our district has a MakerBot and the owner is printing the parts for the Rover for us. The parts list for the rover indicates we should buy the 3.3v version of the Trinket, but the product info page says we should use the 5v version for sensors requiring 5v. The Ping((( info says it runs on 5v as do the micro-servos. Last night, I ordered several of the 3.3v Trinkets (order # 420778) and I want to be sure these will work. I know the website says orders cannot be modified once placed, but if there was some misinformation on the Rover parts list, I hope we can make sure to get the right product.

Thanks again.

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adafruit_support_bill
 
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Re: Trinket Rover

Post by adafruit_support_bill »

According to the Ping sensor documentation for the data pin, this should be OK.
Bidirectional TTL pulse interface on a
single I/O pin can communicate with 5 V
TTL or 3.3 V CMOS microcontrollers

scottw10
 
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Re: Trinket Rover

Post by scottw10 »

Thanks. Next time I'll look a past the product description to the documentation before I bug you. :D

scottw10
 
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Re: Trinket Rover

Post by scottw10 »

Hello-

We've built a Trinket Rover and wired it up, but we are having trouble uploading the sketch. We have put Adafruit_SoftServo.h is our libraries folder. I've tried to follow the instructions for making my Arduino IDE "trinket compatible" but I don't think I've succeeded. I am on Windows Vista 64 bit and get this message:

Binary sketch size: 2,326 bytes (of a 32,256 byte maximum)
avrdude: stk500_getsync(): not in sync: resp=0xe1

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adafruit_support_bill
 
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Re: Trinket Rover

Post by adafruit_support_bill »

Binary sketch size: 2,326 bytes (of a 32,256 byte maximum)
Looks like you do not have the Trinket selected as your board type. The Trinket only has 8K of flash memory, not 32K.

Make sure you can upload the Blink example first as on this page: http://learn.adafruit.com/introducing-t ... rduino-ide

scottw10
 
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Re: Trinket Rover

Post by scottw10 »

I am using the AdafruitArduino IDE on Windows Vista and have finally managed to load the Rover sketch. I opened avrdude.conf in Notebook and changed chip_erase_delay = 900000; to chip_erase_delay = 400000; per FAQ at http://learn.adafruit.com/introducing-trinket/faq. But uploading the sketch returns:

avrdude: error: usbtiny_receive: usb_control_msg: sending control message failed, win error: A device attached to the system is not functioning.

(expected 4, got -5)

However, when switched on, the rover moved forward slowly in a very jerky fashion until within 8 cm of an object, then backs up as intended. It will run forward properly when an object is 30 cm in front of it. I have checked the wiring and the sketch. It feels like it is not responding to the parallax ping properly and I've tried two different units of the same type. Suggestions are appreciated as I have 6 more trinkets on the way and I'm hoping to the use the rover as a robotics club project so I'm determined to get it working right.

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adafruit_support_bill
 
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Re: Trinket Rover

Post by adafruit_support_bill »

However, when switched on, the rover moved forward slowly in a very jerky fashion until within 8 cm of an object, then backs up as intended. It will run forward properly when an object is 30 cm in front of it. I have checked the wiring and the sketch. It feels like it is not responding to the parallax ping properly
It sounds like it is detecting obstacles and avoiding them. What behavior are you concerned about? Is it the jerky motion?

scottw10
 
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Re: Trinket Rover

Post by scottw10 »

The overall operation is not correct. When switched on, it moves erratically in a chattering fashion, sometimes moving forward for a fraction of a second, sometimes moving backward. But if I put my hand 30-50 cm in front of the sensors, it moves forward as it's supposed to. Then at 8 cm from an obstacle, it moves backward as it's supposed to. One interesting thing is that I uploaded the blink program as suggested after changing the avrdude.conf as suggested, it returned the same error message described in the previous post. Then I uploaded the rover sketch after pushing the reset button on the trinket. It returned the same error message as described earlier and I get the behavior described above. However, when the rover is switched off but still connected to the USB port, the blink program runs. I wonder if the problem I'm having is because both programs are loaded and conflicting. I thought hitting reset and uploading a new sketch would overwrite/erase the previous program. Thanks again.

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Re: Trinket Rover

Post by adafruit_support_bill »

It is not too unusual to get an error code, but still upload successfully. You can't really have both programs loaded though. Are you sure that the blinking is not just the bootloader?

I don't have any experience with the Ping sensors. But from looking at the code, it should be either full forward or the reverse turn. Are you using this code exactly as is?
http://learn.adafruit.com/trinket-power ... ource-code

scottw10
 
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Re: Trinket Rover

Post by scottw10 »

I have checked the code thoroughly. The error code is trivial, then? When I connect to USB, the blinking of the bootloader is faster and quits after 10 seconds, then the blink code runs, one second on, one off as described by the code. Maybe I should try another trinket and upload only the rover sketch and see if that solves the problem. It's just weird that it runs full forward as it's supposed to when I put my hand 30-50 cm in front of it until I get within 8 cm, then it backs up as it's supposed to. Without any obstacle, it just sits jerking around in a funny dance acting confused, the led on the ping the red trinket led flashing spasmodically.

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Re: Trinket Rover

Post by adafruit_support_bill »

It is possible that it is getting inconsistent information from the ping sensor and hesitating between forward and reverse modes. I haven't worked with these sensors at all, so I don't know how stable they are.

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