This thread will be about "Arduebot" (not "Ardubot"), the robot which basically is mostly the Arduino Due board itself.
The peg-board is only used to connect half table tennis ball and two motors with superglue and still be able to quickly change the screwed Arduino board:
This is the upside view, the little box with 3 Lipos giving >12V when fully loaded will be superglued to bottom of peg-board:
Ok, if you look carefully you might say that it is not a Due but a Mega on top of the peg-board.
Reason is that I lost a TB6612FNG motor driver by an explosion today, and sadly the connected Arduino Due as well:
Before loosing the next Due [I still have 2 ;-)] I will give the Mega with L293D motor driver a try.
The main reason I will use a Due is its incredible power (84MHz, with overclocking even 114MHz) and the huge ram size (96KB) compared to all other Arduino models.(see my point of view on Arduino Due versus Arduino Zero). It is even powerful enough to drive a 800x600 monochrome VGA monitor by itself with just 3 resisitors (DueVGA).
Next on the basic form of Arduebot -- that is basically the one of the "Asuro" robot I played with 9 years ago:
Asuro was able to run with 0.43m/s maximally by default, tuned it was able to run 1.8m/s with 70mm wheels(!).
I did select the motors and the directly connected wheels (no gears at all) after more than 50 test runs in Motor Test Station (MTS), see this thread:
The best run reported in that thread was 13.59m/s(48.9km/h), but the record was 14.37m/s(51.7km/h):
This nice run did show 13.16 m/s(47.37 km/h) maximal, but during the whole run you can see the speed displayed on a live 320x240 LCD speedometer:
In MTS thread it was discussed that gears are normally needed. I liked the idea or leaving away gears and just directly drive the wheels. The 14,8V motor was definitely powerful enough. I did many experiments with many kinds and diameters and types of wheels:
It turned out that the best were the Lego wheels, and among them 20, 24 and 30mm diameter were best. Record was achieved with 24mm, and that is the reason I go with that wheel for now.
Btw, the most important act determining success or failure of a wheel is balancing out the wheel when connecting with superglue to motor axis:
Another aspect discussed in MTS thread was that circular speed is proportionally, but not directly comparable with the potention linear moving speed. I did a small Uno bot based on 12V motors that achieved 9.89m/s(35.6km/h) in MTS. Linearly they achieved only 3.1m/s, good below my target speed of 5m/s(18km/h):
What the youtube video of the 3.1m/s run in that posting shows is that the robot does run totally straight, without any help with both motors powered fully. I recently tested other bot platforms with a 3rd (or even 4th) small wheel instead of half table tennis ball. These robots cannot go straight, I needed 15 runs with the circular robot to get a slowmo video allowing me to measure linear speed by inspecting slowmo frame by frame.
So the two just mentioned robot platforms were good for two things:
- don't use a 3rd all-direction wheel, use half of a table tennis ball
- I was surprised that maximal circular speed of 1.57m/s(5.6km/h) of circular robot was not much better than the linear speed of 1.26m/s(4.5km/h)
I did run both platforms with a V1 Arduino Motor Shield, and tried a nodemcu (ESP8266) motor shield as well allowing for Wifi remote control:
But I am interested in autonomous robot, and would need the ESP8266 not for remote control in Arduebot, bot for streaming video back to laptop. One thing I am interested in is line following (yes, really), but speedy line following. In 2013 "Thunderstorm" robot won a line following contest with 3.1m/s(!) speed on average(!!):
This number is the basis for my maximum linear speed of 5m/s target
I mentioned the plan of having a camera on Arduebot, and the plan is to use it for linefollowing as well. Taking a picture just before the front of Arduebot would be equivalent to using infrared LED and photo resistors I did back in 2007. But taking more of the picture ahead into account should give Arduebot a view of the line follwing course "in the near future" as well, which should hopefully make control of speedy linefollowing better.
The camera is a cheap ov7660 VGA camera, but for line follwing 320x240 or even 160x120 or 80x60 black&white pictures should be good enough, and thanks to the MHz of the Due processing the pictures in real time should be doable -- next part project will be to learn how to connect and use the ov7670 camera:
Ok, this should be a first posting on Arduebot, will update when new things happen (hopefully no explosions anymore),