RoboPi - the most powerful Robot controller for the Raspberry Pi (adds 8 core co-processor)

mikronauts · May 24, 2014, 2:16pm

Mikronauts RoboPi adds an eight-core 32-bit microcontroller running at 100Mhz to the Raspberry Pi in order to off-load hard real time I/O and allow more precise timing than Linux running on the Pi allows.

RoboPi Features

Parallax Propeller P8X32 eight core 32 bit Risc microcontroller running at 100Mhz
Each of the eight cores provides up to 25MIPS as most instructions take only 4 clock cycles
three ten-pin Mikronauts I/O module expansion connectors (P0-P7, P8-P15, P16-P23)
24 servo compatible headers on P0..P23Screw terminal for providing external power for Servo connectors P0-P15
8 servo compatible headers for an eight channel 0-5V MCP3208 analog to digital converter
512Kbit boot EEPROM for the Propeller
4 pin I2C expansion header for the Raspberry Pi
4 pin I2C expansion header for the Propeller
5 pin HCOM connector for use with PropPlug in stand alone operation (optional)
Mikronauts EZasPi prototyping board can stack below RoboPi
Mikronauts Pi Jumper can stack on top of RoboPi
Mikronauts SchoolBoard ][ and other Propeller products are compatible with RoboPi

For more information, including more photos and user documentation, please visit:

http://www.mikronauts.com/raspberry-pi/robopi/

Please do not hesitate to ask any questions you may have!

You can now buy RoboPi directly from us, or from our Ebay listings by searching for RoboPi on Ebay

mikronauts · May 24, 2014, 2:59pm

Hi bdk6,- RoboPi is an

Hi bdk6,

- RoboPi is an all-in-one Robot controller specifically for the Raspberry Pi, that is very differentiated

- The kit, minus chips, is $24.95 qty.1, which by the way is the approximate cost of the components it comes with from Digikey

- The chip’s cost more in Canada than the states, thus I have to charge $49.95 qty.1 for the full kits

- I have to get them assembled in Canada, I originally intended to only sell kits, but some customers asked for the A&T option

- 3x$35 = $105, so my A&T board is not quite the cost of three Pi’s

- Pi is made in extremely large volume, by a non-profit, with subsidized pricing from Broadcom for the processor, and subsidized assembly & manufacturing … RoboPi is made in low volume and not subsidized

RoboPi was intended for educational users who value building a kit, and it is very affordable for hobbyists as a lite kit.

Regards,

Bill

mikronauts · May 24, 2014, 5:00pm

clarifications for you

Hi Maxhirez,

Thank you for your reponse, and I will attempt to address each of your points.

"The point of the Pi is its low cost. Adding a peripheral that costs close to 3x the mother processor(without including the Pi itself) defeats the purpose a little bit."

I tend to think of the Pi as an add on to RoboPi

The Propeller is great for hard real time control, but is not powerful enough for vision, WiFi, etc.

The Raspberry Pi, while great for many things, is not great for hard real time control.

RoboPi and a Raspberry Pi is an example of a happy mariage, where the sum is geater than the parts.

Being well aware of the Raspberry Pi’s unusually low subsidized price, RoboPi was designed to be sold as a kit for education and those that need a very powerful robot controller with hard real time control.

You are comparing to an assembled and tested RoboPi, which is not how it is designed to be marketed, precisely due to the cost of components, non-recurring engineering costs, and low quantity assembly costs.

I do have a surface mount volume version, meant to be sold in volume, on the drawing boards, but I am not sure I will produce it due to the large number of boards I’d have to build before selling even one, due to inventory carrying costs.

The “RoboPi Lite Kit”, which includes all parts but the three integrated circuits, is $24.95 qty.1

The parts - including the PCB cost - if bought by an individual for one or few boards is more than that.

The three integrated circuits currently cost (I just checked prices for you)

$ 7.99 USD http://www.digikey.com/product-detail/en/P8X32A-D40/P8X32A-D40-ND/1136005
$ 4.18 USD http://www.digikey.com/product-detail/en/MCP3208-CI%2FP/MCP3208-CI%2FP-ND/305928
$ 1.61 USD http://www.digikey.com/product-search/en?x=18&y=16&lang=en&site=us&KeyWords=24LC512-I%2FP-ND
------
$13.78 USD
$ 8.00 USD Digikey s/h for USA
------
$21.78 USD

I offer “RoboPi Full Kit” for $49.95 USD for the convenience of my customers, as I hardly make any additional markup on the full kits.

I do get somewhat better pricing for the parts, but not as much as you would think as I have to buy the chips from Canadian suppliers and suffer the slings and arrows of inflated pricing, taxes etc. Parallax gives me a better price per chip - but after shipping, brokerage, taxes, its cheaper to buy in Canada. Go figure.

The techs who do assembly for me cost $25/hr, or equivalent in “per piece pricing”, and will only assemble lots of 10 or higher. It takes 15 to 20 hours to assemble and test ten boards.

If you check with other North American product designers regarding their costs for low volume products that they have to get assembled and tested in North America, and you will find my price is actually quite good.

"As I point out in this tutorial, you don’t even need an Arduino to control your robot with a Raspberry Pi."

Please see the “SPRITE” Rasberry Pi based robot in the January 2014 Servo magazine. I built such a simple Pi robot.

I have some information on SPRITE on my site:

http://www.mikronauts.com/robot-zoo/sprite/

"If you want to control multiple servos, Adafruit offers this i2c option which you can usually find for less than $15 on eBay."

You mean: http://www.adafruit.com/product/815

$14.95+s/h

The ebay ones are likely clones from Asia.

And you cannot compare the power of RoboPi with an eight core 32 bit risc processor, with an eight channel 12 bit ADC, and 512Kb EEPROM, to a $15 board based on a $1.80 PWM LED controller.

"One shortcoming of the (admittedly powerful) Propeller system that I ran up against almost immediately when Duane first converted me to the Cult of Parallax is most prop boards’ lack of ADCs-and with my quick examination of this post I don’t see anything about them listed for this platter-are they included?"

As the product page shows:

RoboPi Lite Kit - no IC’s included
RoboPi Full Kit - MCP3208 tweleve bit ADC, 512KBIT EEPROM, and Propeller inclulded
RoboPi Assembled & Tested - of course all chips are included.

"I hope you’ll forgive me for my skepticism"

Of course I do!

You did not get the intent of RoboPi, nor how it is used.

Think of (RoboPi+Pi) as a $134.95 fully assembled and tested ARM + 8 worker core powerful robot controller.

It is a gestalt product, not really a peripheral, marketed to education as a kit to lower costs, but with industrial and sophisiticated users who realize the value.

See http://www.mikronauts.com/robot-zoo/hexpi-hexapod-pi-robot/ for one application

"and that you’ll stay with us as a member, mikronauts. You’re obviously the kind of talented intelligent member we pride ourselves on having at LMR, but while I wish you the best in this endeavor,"

Thank you, I will stay a member, and I do appreciate your kind wishes.

"I don’t think I see this as being a really useful tool or one that I’d recommend. If someone has the skills it takes to build and use it they will probably see more economical and targeted solutions to their particular situations, and if they are just starting out, the cost will be prohibitive."

RoboPi is certainly not for everyone, however I will disagree (and so will my customers) about RoboPi not being a useful tool.

The intended target for RoboPi is educational buyers in quantity, or hobbyists who will build their own. In an educational setting, the school can order the parts separately, and get the electronics class to assemble them.

In a hobbyist setting, a Propeller enthusiast will already have Propellers and EEPROM’s, and might have the ADC - which he can order if he does not.

I have some industrial customers who are happily using RoboPi, so there are many people who find it to be the right solution for their situation.

"However, I do commend you for your work and your effort. I love both sets of technologies you’re incorporating."

Thank you.

William Henning
Mikronauts

roxanna77 · May 25, 2014, 7:10am

**I think the RoboPI is quite awesome! **

I think the RoboPI is quite awesome and will order one today. The cost is actually quite reasonable, and I agree, the Pi is the add on to the RoboPi. And this is pretty much all made in North America, right?
And, I am so glad it does not have a motor controller on it, as that is the most likely thing to fry on a robot, especially if its a bigger bot with hefty motors. Motor controllers need to be sized for the application.

Now a Raspberry Pi has something I want, as before I had only interest, not want for one.

mikronauts · May 25, 2014, 5:55pm

Thank you Roxanna!Designed

Thank you Roxanna!

Designed in Canada, kitted in Canada, most parts from North American suppliers (though even those are probably mostly from overseas), and assembled & tested in Canada.

I see you understand about the lack of a dual H bridge!

I had three reasons for not putting one on:

1) There is no one right H-Bridge (as you rightly pointed out, it needs to be sized for the application)

2) No room left on the board, without squeezing everything so much it would be difficult to assemble

3) It would add to the price

You have pointed out a new one, that I realized, but never itemized:

4) H-Bridges are the most likely part to fry

(I have two other robot controller boards, one has an integrated L293D, and one an L298)

I do support PWM motor control with my firmware, API’s and protocol, but I envisioned people wanting to choose their own motor drivers for robots sophisticated enough to need a RoboPi/Pi combo.

For my test bots, I currently use:

(cheapest) L9110 module (0.5A per channel)
(next cheapest) L293D (1A per channel)
(inexpensive) L298 module (2A per channel)
(higher power) Cytron (sp?) 15A per channel controller
(ridiculous) unnamed 320A (theoretical) controller

The last two are ridiculously over powered for most home/educational bots

My HexPi build is using 18 servos, no H-Bridge needed

You will have a LOT of fun with the RoboPi/Pi combo!

Best Regards,

Bill

mikronauts · May 27, 2014, 1:37pm

Forgot to mention…

RoboPi works well stand-alone.

All you need to add is a Parallax PropPlug, and a regulated 5V supply.

I’ve been using it as a DAQ board for some projects.

mikronauts · June 2, 2014, 2:14pm

RoboPi v0.81 software is now available

This version adds:

readDistance(pin) for HCSR-04 ultrasonic range sensor
improves servo and PWM resolution to 5 microsecond timing grain

The new software is available on the product page at:

http://www.mikronauts.com/raspberry-pi/robopi/

Please note:

readDistance() should also work with the Parallax Ping sensor, and may also work with the SeeedStudio range sensor.

I will be testing both of those sensors shortly.

mikronauts · June 30, 2014, 10:28pm

User Docs updated to v0.81

I updated the user manual to reflect the latest version of the readDistance() API for ultrasonic sensors, and added information on how to connect them to RoboPi.

mikronauts · October 11, 2014, 2:57pm

Python sample code

I am putting the finishing touches on the v0.85 software/documentation release for RoboPi.

Today I translated the new C/C++ RoboPiLib examples to my new Python interface, adding

analogRead.py
analogWrite.py
digitalRead.py
digitalWrite.py
servoWrite.py
readDistance.py

Of course, there are C versions of the same samples as well.

------------- -------------<code>#!/usr/bin/python import RoboPiLib as RoboPi import time as time RoboPi.RoboPiInit("/dev/ttyAMA0",115200) HC_SR04 = 16 while 1:   print "Distance is ", RoboPi.readDistance(HC_SR04)   time.sleep(0.1)</code>

------------- [/code] -------------

There is also a resetRoboPi.c with a resetRoboPi.py coming as soon as I sort out the issue I am having with setmode.

mikronauts · October 21, 2014, 9:11pm

RoboPi Python support & samples released!

UPDATE: Python support for RoboPi !!!

The new RoboPi v0.85 software release provides:

v0.85 of the C RoboPi Lib
C sample code using RoboPiLib
Python 2.7 support
Python 3.2 support
Python sample code
Compiled test utilities in the C Demos folder

This release took longer than anticipated due to other work and “real life ™”

You can find RoboPi v0.85 libs & demos on the product page at:

http://www.mikronauts.com/raspberry-pi/robopi/