Categoria: Sem categoria

python-ev3dev v2 available in beta (just for stretch)

The highlights include:

• New classes are available for coordinating motors: ev3dev2.motor.MotorSet, ev3dev2.motor.MoveTank, ev3dev2.motor.MoveSteering, and ev3dev2.motor.MoveJoystick.
• Classes representing a variety of motor speed units are available and accepted by many of the motor interfaces: see our docs to learn more.
• Friendlier interfaces for operating motors and sensors: check out ev3dev2.motor.Motor.on_for_rotations and the other on_for_* methods on motors.
• Easier interactivity via buttons: each button now has wait_for_pressed, wait_for_released and wait_for_bump
• Improved ev3dev2.sound.Sound and ev3dev2.display.Display interfaces
• New color conversion methods in ev3dev2.sensor.lego.ColorSensor

Found my BT BLE dongle with the Broadcom chipset.

It’s a “Targus Bluetooth v4.0 Dual-mode Dongle ACB75A” that is sold at Staples.

dmesg:

usb 1-1: new full-speed USB device number 9 using xhci_hcd
usb 1-1: New USB device found, idVendor=0a5c, idProduct=21e8
usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 1-1: Product: BCM20702A0
usb 1-1: Manufacturer: Broadcom Corp
usb 1-1: SerialNumber: 5CF370878D54
Bluetooth: hci1: BCM: chip id 63
Bluetooth: hci1: BCM: features 0x07
Bluetooth: hci1: BCM20702A
Bluetooth: hci1: BCM20702A1 (001.002.014) build 0000
bluetooth hci1: Direct firmware load for brcm/BCM20702A1-0a5c-21e8.hcd failed with error -2
Bluetooth: hci1: BCM: Patch brcm/BCM20702A1-0a5c-21e8.hcd not found

hciconfig:

hci1:	Type: Primary  Bus: USB
	BD Address: 5C:F3:70:87:8D:54  ACL MTU: 1021:8  SCO MTU: 64:1
	UP RUNNING 
	RX bytes:1052 acl:0 sco:0 events:63 errors:0
	TX bytes:4898 acl:0 sco:0 commands:63 errors:0
	Features: 0xbf 0xfe 0xcf 0xfe 0xdb 0xff 0x7b 0x87
	Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3 
	Link policy: RSWITCH SNIFF 
	Link mode: SLAVE ACCEPT 
	Name: 'xxxx'
	Class: 0x1c010c
	Service Classes: Rendering, Capturing, Object Transfer
	Device Class: Computer, Laptop
	HCI Version: 4.0 (0x6)  Revision: 0x1000
	LMP Version: 4.0 (0x6)  Subversion: 0x220e
	Manufacturer: Broadcom Corporation (15)

so it’s a Broadcom BCM20702A chipset and my Ubuntu doesn’t find the firmware needed. It still works without firmware but I went after it.

This site helped:

wget https://s3.amazonaws.com/plugable/bin/fw-0a5c_21e8.hcd
sudo cp fw-0a5c_21e8.hcd /lib/firmware/brcm/BCM20702A1-0a5c-21e8.hcd

I got my script working with 6 LEGO BLE devices. And 7. And even 8:

But latency isn’t great (with 8 I had to decrease the loop period from 1 second to 0.25 to prevent connection drops and even send the initial command twice to the Handset to hold the session) so even if it supports 14 sessions I doubt that we can make good use of 14 LEGO LPF2 hubs with just one dongle.

To reduce latency we can add more dongles. But even so, when a command takes 0.2 to 0.3 seconds to complete before we can send the next one, it’s hardly interesting for robotics. A Powered Up based robot will require a real autonomous device, able to read its own sensors and react on the fly, not with half a second round trip delay to the “brain”.

Also tried the script without the firmware. It works but with a few “connect error: Function not implemented (38)”.

And also re-tried the Cambridge CSR 4.0. It clearly states that it can’t handle the sixth: “connect error: Too many links (31)”

Yeap. CSR 4.0 on Ubuntu can control 5 different BLE devices:

Bash script:

#!/usr/bin/env bash

#usage: ./rgbled.sh hci0

HCI=$1

#DELAY=0.03
DELAY=0

#colors
OFF=0
PINK=1
PURPLE=2
BLUE=3
LIGHTBLUE=4
LIGHTGREEN=5
GREEN=6
YELLOW=7
ORANGE=9
RED=9
WHITE=A

#hubs
PUPA="90:84:2B:06:AB:5D"
PUPB="90:84:2B:03:CA:6E"
BOOSTA="00:16:53:A3:47:EA"
HANDSETA="A4:34:F1:CE:DC:A2"
WEDOA="A0:E6:F8:1B:FF:9B"

function remoteLED () {
    gatttool -i $HCI -b $PUPA --char-write-req --handle 0x0e --value 080081321151000$1
    sleep $DELAY
    gatttool -i $HCI -b $PUPB --char-write-req --handle 0x0e --value 080081321151000$1
    sleep $DELAY
    gatttool -i $HCI -b $BOOSTA --char-write-req --handle 0x0e --value 080081321151000$1
    sleep $DELAY
    gatttool -i $HCI -b $HANDSETA --char-write-req --handle 0x0b --value 080081341151000$1
    sleep $DELAY
    gatttool -i $HCI -b $WEDOA --char-write-req --handle 0x3d --value 0604010$1
    sleep $DELAY
}

# activate notifications and keep changing colors
gatttool  -i $HCI -b $PUPA --char-write-req --handle 0x0f --value 0100
sleep $DELAY
gatttool -i $HCI -b $PUPB --char-write-req --handle 0x0f --value 0100
sleep $DELAY
gatttool -i $HCI -b $BOOSTA --char-write-req --handle 0x0f --value 0100
sleep $DELAY
gatttool -i $HCI -b $HANDSETA --char-write-req --handle 0x0c --value 0100
sleep $DELAY

while :
do
    for color in $OFF $PINK $PURPLE $BLUE $LIGHTBLUE $LIGHTGREEN $GREEN $YELLOW $ORANGE $RED $WHITE; do
        remoteLED $color
        sleep 1
    done
done

About two years ago I had a dual SBrick “train” setup controlled with my EV3. I never really got much far because there were some hiccups when using one USB BLE dongle to control two SBrick at the same time that didn’t occur with my Ubuntu laptop (same dongle, a CSR 4.0).

By that time, the ev3dev had a BlueZ stack much older than my Ubuntu so I decided to wait and as usual I forgot about it.

Today I’m testing how many Powered Up hubs I can control at the same time with just one BLE “client”. Just a simple bash script, changing the RGB LED colors of the hubs at the same time.

My laptop could control 2. But started to had issues with 3, failing some commands:

Characteristic Write Request failed: Request attribute has encountered an unlikely error

Perhaps sending 3 gatttool commands in-a-row was too much so added a small delay. It got worst:

connect error: Connection timed out (110)

Tuning to a small delay (0.03) seems to be the best but is strange.

Now this laptop is no longer the same I had and it now has an onboard BLE 4.2 chipset, from Intel. Not sure which version.

But I still have the CSR 4.0 dongle on the Ev3 over the desk. So let’s try same script with it.

No errors at all. Not even with 0 delay.

These last years David has been doing a great job with ev3dev kernel so my EV3 and my Ubuntu laptop are now pretty close: (4.14.58-ev3dev-2.2.1-ev3 against 4.15.0-29-lowlatency #31-Ubuntu SMP PREEMPT) so I don’t think this is a BlueZ issue.

I read somewhere that CSR 4.0 allows 5 sessions. So I need to test my script again with more LEGO hubs. But wonder why the Intel only handles two.

Now the script:

#!/usr/bin/env bash

#colors
OFF=0
PINK=1
PURPLE=2
BLUE=3
LIGHTBLUE=4
LIGHTGREEN=5
GREEN=6
YELLOW=7
ORANGE=9
RED=9
WHITE=A

#hubs
PUPA="90:84:2B:06:AB:5D"
PUPB="90:84:2B:03:CA:6E"
BOOSTA="00:16:53:A3:47:EA"

DELAY=0.03

function remoteLED () {
    gatttool -b $PUPA --char-write-req --handle 0x0e --value 080081321151000$1
    sleep $DELAY
    gatttool -b $PUPB --char-write-req --handle 0x0e --value 080081321151000$1
    sleep $DELAY
    gatttool -b $BOOSTA --char-write-req --handle 0x0e --value 080081321151000$1
    sleep $DELAY
}

# activate notifications and keep changing colors
gatttool -b $PUPA --char-write-req --handle 0x0f --value 0100
sleep $DELAY
gatttool -b $PUPB --char-write-req --handle 0x0f --value 0100
sleep $DELAY
gatttool -b $BOOSTA --char-write-req --handle 0x0f --value 0100
sleep $DELAY

while :
do
    for color in $OFF $PINK $PURPLE $BLUE $LIGHTBLUE $LIGHTGREEN $GREEN $YELLOW $ORANGE $RED $WHITE; do
        remoteLED $color
        sleep 1
    done
done

Buy the way, controlling 2 Powered Up “Hub NO.4” and 1 BOOST “Move Hub” at the same time from a single EV3  is already pretty good (if the old hiccups problems are fixed): that’s potentially 8 more motors!

[edit]

Now this is interesting:

I have news, because i did a test. The Broadcom BCM20702 Bluetooth Dongle can handle up to 14 BLE device connections simulateous.
And overall it’s a lot faster than this one from Cambridge Silicon Radio (can handle a max. of 5 BLE device connections simulateous).

Need to search my drawers… almost 100% sure I had a Broadcom LE USB dongle that gave up because ev3dev didn’t like it as much as the Cambridge CSR.
Also Raspberry Pi is Broadcom… time to get back to BrickPi3.

with a captcha plugin

Ben Hughes asked for the code for the demo video “LEGO MINDSTORMS EV3 controlling Powered UP motor” so here it is:

#!/usr/bin/env bash

event_left='*code 105 (KEY_LEFT), value 1*'
event_right='*code 106 (KEY_RIGHT), value 1*'
event_down='*code 108 (KEY_DOWN), value 1*'
event_up='*code 103 (KEY_UP), value 1*'
event_enter='*code 28 (KEY_ENTER), value 1*'

function finish {
    # terminate all subshells
    kill 0
    # reset all motors
    gatttool -i hci0  -b 90:84:2B:06:AB:5D --char-write-req --handle 0x0e --value 0800810011510000
    gatttool -i hci0  -b 90:84:2B:06:AB:5D --char-write-req --handle 0x0e --value 0800810111510000
}
trap finish EXIT



{
    while :
    do
        gatttool -i hci0  -b 90:84:2B:06:AB:5D --char-write-req --handle 0x0e --value 0800810011510000
        sleep 0.35
    done
}&


while :
do
    evtest '/dev/input/event1' | while read line
    do
#        echo $line
        case $line in
            $event_left)
                echo "LEFT"
                gatttool -i hci0 -b 90:84:2B:06:AB:5D --char-write-req --handle 0x0e --value 0800810011510060
                sleep 0.1
                ;;
            $event_right)
                echo "RIGHT"
                gatttool -i hci0 -b 90:84:2B:06:AB:5D --char-write-req --handle 0x0e --value 08008100115100A0
                sleep 0.1
                ;;
           $event_down)
                echo "DOWN"
                gatttool -i hci0 -b 90:84:2B:06:AB:5D --char-write-req --handle 0x0e --value 0800810011510000
                sleep 0.1
                ;;
           $event_up)
                echo "UP"
                ;;
           $event_enter)
                echo "ENTER"
                ;;
        esac
    done
done