Making a Rpi Pico Based Smart Vehicle
ProjectsJun 306 / 6Jul 68h ago
tlfong01:Testing Plan of Pico Smart Vehicle Part 2, Moving Two Motors
It appears that I can no more edit/append my own post if it is two or three days old . So my workaround is “quote something and reply”. This makes my incremental short project progress report like a long blog, where other readers can comment and make suggestion in time. I am thinking of later using a blog site to report my progress, so the late readers can read a coherent article.
Update 2021jul04hkt1307
Errata: I just found out that this pi-top forum is using the Discourse software: Discourse (Software 2013 by Jeff Atwoodet al) – Wikipedia, which I never heard of, and therefore have misunderstood the working and restriction of newbie/low level users. Eg, I wrongly thought that I could not edit my own posts after a couple of days. Actually if I have gone up high levels, I can edit my own post within 30 days. Also Discourse seems to encourage “long form” input, and “infinite scrolling”, which I don’t have any idea about. I am used to StackExchange’s short form Q&A (Question and Answers), not discussion forums, so I need to change my mindset. Anyway, I need to know more about Discourse, before I can make up my mind how to present my project.
Anyway, now I am reading pi-top 4 DIY/Robotic Kit’s documents to get a rough idea of how their rovers look like, so my Smart Pico Vehicle (SPV v1.0) can follow their ideas somewhat. Here are the pi-top 4 references I am reading:
(1)pi_top_rover_2021jul03011134×589 129 KB
(2) pi-top 4 DIY
It appears that the pi-top 4 DIY edition is still a work in progress. So I think I can for now DIY my project Smart Pico Vehicle flexibly, perhaps also let other readers give brainstorming ideas.
So I am now reading more N20 motor documentation, and perhaps rapid prototyping a 4WD, ie Four Wheel Drive, with four N20 motors.n20_motor_spec_2021jul03011024×492 116 KB
This gloomy lock down Sunday morning I was browsing casually around the forum and I was glad to see other users also making 4WDs, using pi-top Robotic kits. I found them using “Mecanum Wheels” which I read long time ago, but never have a chance playing with the real thing. I think these strange looking wheels need advanced, scary maths. So for now, humble me will stick to simple, plain wheels.
SPV (Smart Pico Vehicle) v0.1 Assembly Notespico_4wd_2021jul04021024×503 167 KB
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References
(2) 10 Software Packages You Can Add to Your Pi-Top [4] – Elijah Phillips, 2020jun15
(3) Further – Easy to Use STEM Software for Schools – pi-top.com
(4) Raspberry Pi Pico by Raspberry Pi – ClassRoomEshop Hongkong/Taiwan HK$40
CLASSROOM eShop
Raspberry Pi Pico (board only)
Taiwan eShop: https://bit.ly/2MeEvNM 1 x Raspberry Pi Pico (board only) Raspberry Pi Pico, the new flexible microcontroller board from Raspberry Pi. Board Specifications Raspberry Pi Pico is a low-cost, high-performance microcontroller…Reply
SPV (Smart Pico Vehicle) v0.1 Assembly Notes
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I can no longer edit/append to my old post, so I continue by a reply.
I found Pi-top [4] Rover with ultrasonic sensor and camera too complicated. So I am thinking of using the simpler MMK (Motors and Motion Kit) as a reference.
pi_top_mmk_2021jul05011024×371 147 KB
In other words, I am starting off with a 2WD, and only later scale it up to a 4WD.
So I am assembling my Pico 2WD with 47mm diameter simple plain wheels. But I am jealous seeing other guys building 4WD’s with Mecannum wheels of 60mm diameter, I think. So I have decided to also use 60mm plain wheels, to make it easier to convert to Mecanum later.
spv_2wd_v01_2021jul05011024×313 103 KB
Which Motor Driver for SPV (Smart Pico Vehicle) v0.1 2WD
Last time I used the simple and newbie friendly MX1508 motor driver for basic testing and found everything OK. MX1508 does not have easy PWM speed control features. So this time I am using a more sophisticated motor driver, the
Toshiba TB6612FNG Dual DC Motor Driver.
References
(1) Moebius 60mm Mecanum Wheel Omni Tire Compatible with TT Motor LEGOs for Arduino DIY Robot STEM Toy Parts – AliExpress US$25
25.77US $ 7% OFF|MOEBIUS 2020 HOT 60mm Mecanum Wheel Omni Tire Compatible…
Smarter Shopping, Better Living! Aliexpress.com
(2) Pi-top [4] 4WD Mecannum – forum.pi-top.com 2021may25
(3) TB6612FNG Dual Motor Driver Carrier – Pololu Robotic and Electronics
(4) The Review of DC Motor Drivers: L298N, TB6612FNG and LV8406T – MakeBlock, 2014jan
(5) TB6612FNG Dual DC Motor Driver IC Datasheet, Toshiba, 2007jun
sparkfun.com
TB6612FNG.pdf
202.55 KB
(6) TB6612FNG Dual DC Motor Driver Module – AliExpress, US$1.5
3.53US $ 30% OFF|TB6612FNG Dual Motor Driver Module For Arduino…
Smarter Shopping, Better Living! Aliexpress.com1Reply
Which Motor Driver for SPV (Smart Pico Vehicle) v0.1 2WD
Last time I used the simple and newbie friendly MX1508 motor driver for basic testing and found everything OK. MX1508 does not have easy PWM speed control features. So this time I am using a more sophisticated motor driver, the
Toshiba TB6612FNG Dual DC Motor Driver.
Now I am testing the N20 motor with encoder. I found the tutorials below on encoders and kit very useful
I used 6V to power both N20 motors, and used a scope to display the quadrature motor encoder outputs A, B of both motors, as shown below.
n20_encoder_outpit_2021jul06011024×495 146 KB
This is the hardware setup of SPV 2WD v0.1, with two N20 motors and 60mm simple plain wheels.
Next step is to setup and test the Toshiba TB6612FNG Dual DC Motor Driver, to control the direction and speed (using PWM) of the SPV 2WD’s two N20 DC motors.
Appendices
Appendix A – TB6612FNG Programming Cheat Sheet
tb6612fng_summary_2021jul06011134×549 90.5 KBtb6612fng_summary_2021jul06021012×740 148 KB
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References
(1) Motor Encoders with Arduino – Andrew Kramer’s Research, 2016jan
Bot Blog – 2 Jan 16
Motor Encoders with Arduino – Bot Blog
A tutorial on the use of quadrature encoders with Arduino. Encoders are useful for speed control and pose estimation in robotics applications.
Est. reading time: 6 minutes
(2) Magnetic Encoder Pair Kit for Micro Metal Gearmotors, 12 CPR, 2.7-18V (old version) – Pololu
pololu.com
Pololu – Magnetic Encoder Pair Kit for Micro Metal Gearmotors, 12 CPR,…
Add quadrature encoders to your LP, MP, or HP micro metal gearmotors (extended back shaft version required) with this kit that uses a magnetic disc and hall effect sensors to provide 12 counts per revolution of the motor shaft. The sensors operate…
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