Found a robot arm in the garage (as you do!)
As you do on a Saturday, I found an old Maplin (who remembers them, before they stopped trading!?) robot arm with a USB connector.
I was looking around online to purchase a new one and of course I got carried away and moved from £50, to £250 to £400 devices - I even got carried away and looked at the £7000 versions, but alas - I am being money conscious nowadays and thought, well, if I have this old one, SURELY I can make it work.
I had a quick google and indeed the robot arm was from Maplin. I unscrewed the casing and found the 4 x D batteries inside that had an "expiry date of Mar 2019". That tells you more than enough. This unit had gotten quite dusty knocking around in the garage. I "probably" did something with it back in 2016-2018 ish timeframe, I cannot recall. As I've mentioned, I kind of got distracted by the Corporate world around then and lost my focus - fret not, it is returning!
I noticed that it has the USB connected and adapter on the back - again, more googling and I see that it did come with a CD-ROM and the software was for Windows ONLY.
Sigh.
I was going to leave it as an object d'art on the bookcase and go and spend that hard earned cash, when I thought, "No, I will find something on the good old inter-webs".
It was NOT easy - but indeed, I did find something, that led me to something else, that led me to the GOLD.
There was the GOLD - a link to this website:
https://notbrainsurgery.livejournal.com/38622.html
That had some C code and the usage of a libusb C library:
Turns out that link it dead, BUT the library still exists, it's just moved to here:
I've ordered new 4 x D batteries, I actually couldn't get a better price than Amazon delivery - I know, I know, but hey - it gives me time to get the software working before they arrive tomorrow :-D
I would prefer to get the C code running on a raspberry pi, which should be simple enough and then I can hook that up to take commands from remote OR even just hook it up with "other things" to make it a bit more autonomous. Oooooo, I just remembered I have a couple of the Raspberry Pi Camera modules knocking around that I found recently too.
Okay, this could end up being a bit Frankensteins monster, but it'll be a fun use of time and re-invigorate that creative urge that Corporate World (and social media) etc... has drained me out of.
Which also reminds me, this is an interesting video to watch - if you can, give it a watch, this is basically how I've felt now for 3-4 years and I acted upon it about 2 years ago and I am now starting to feel myself again (yes, I deleted my facebook / instagram apps from my phone & I feel so much better talking to myself in my own head! I know that sounds wrong, but it feels so right. give it a try.
Will update with progress.
UPDATE:
Here's the C code as a starter:
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <string.h>
#include <libusb-1.0/libusb.h>
#define EP_INTR (1 | LIBUSB_ENDPOINT_IN)
#define ARM_VENDOR 0x1267
#define ARM_PRODUCT 0
#define CMD_DATALEN 3
libusb_device * find_arm(libusb_device **devs)
{
libusb_device *dev;
int i = 0;
while ((dev = devs[i++]) != NULL) {
struct libusb_device_descriptor desc;
int r = libusb_get_device_descriptor(dev, &desc);
if (r < 0) {
fprintf(stderr, "failed to get device descriptor");
return NULL;
}
if(desc.idVendor == ARM_VENDOR &&
desc.idProduct == ARM_PRODUCT)
{
return dev;
}
}
return NULL;
}
int main(int ac, char **av)
{
if(ac!=4)
{
fprintf(stderr,"Usage: armedgetest CMD0 CMD1 CMD2\n");
return 1;
}
unsigned char cmd[3];
cmd[0]=(unsigned char)strtol(av[1],NULL,16);
cmd[1]=(unsigned char)strtol(av[2],NULL,16);
cmd[2]=(unsigned char)strtol(av[3],NULL,16);
libusb_device **devs;
libusb_device *dev;
struct libusb_device_handle *devh = NULL;
int r;
ssize_t cnt;
r = libusb_init(NULL);
if (r < 0)
{
fprintf(stderr, "failed to initialize libusb\n");
return r;
}
libusb_set_debug(NULL,2);
cnt = libusb_get_device_list(NULL, &devs);
if (cnt < 0)
return (int) cnt;
dev=find_arm(devs);
if(!dev)
{
fprintf(stderr, "Robot Arm not found\n");
return -1;
}
r = libusb_open(dev,&devh);
if(r!=0)
{
fprintf(stderr, "Error opening device\n");
libusb_free_device_list(devs, 1);
libusb_exit(NULL);
return -1;
}
fprintf(stderr, "Sending %02X %02X %02X\n",
(int)cmd[0],
(int)cmd[1],
(int)cmd[2]
);
int actual_length=-1;
r = libusb_control_transfer(devh,
0x40, //uint8_t bmRequestType,
6, //uint8_t bRequest,
0x100, //uint16_t wValue,
0,//uint16_t wIndex,
cmd,
CMD_DATALEN,
0
);
if(!(r == 0 && actual_length >= CMD_DATALEN))
{
fprintf(stderr, "Write err %d. len=%d\n",r,actual_length);
}
libusb_close(devh);
libusb_free_device_list(devs, 1);
libusb_exit(NULL);
fprintf(stderr, "Done\n");
return 0;
}
gcc armedgetest.c -o armedgetest
/usr/bin/ld: /tmp/ccRoDrnJ.o: in function `find_arm':
armedgetest.c:(.text+0x37): undefined reference to `libusb_get_device_descriptor'
/usr/bin/ld: /tmp/ccRoDrnJ.o: in function `main':
armedgetest.c:(.text+0x18b): undefined reference to `libusb_init'
/usr/bin/ld: armedgetest.c:(.text+0x1cb): undefined reference to `libusb_set_debug'
/usr/bin/ld: armedgetest.c:(.text+0x1dc): undefined reference to `libusb_get_device_list'
/usr/bin/ld: armedgetest.c:(.text+0x244): undefined reference to `libusb_open'
/usr/bin/ld: armedgetest.c:(.text+0x27e): undefined reference to `libusb_free_device_list'
/usr/bin/ld: armedgetest.c:(.text+0x288): undefined reference to `libusb_exit'
/usr/bin/ld: armedgetest.c:(.text+0x2f8): undefined reference to `libusb_control_transfer'
/usr/bin/ld: armedgetest.c:(.text+0x338): undefined reference to `libusb_close'
/usr/bin/ld: armedgetest.c:(.text+0x349): undefined reference to `libusb_free_device_list'
/usr/bin/ld: armedgetest.c:(.text+0x353): undefined reference to `libusb_exit'
collect2: error: ld returned 1 exit status
It seems that Ubuntu installs the library however, you have to make sure you reference it when compiling:
(networkx) tony@tony-magicbook:~/dev/robot/arm$ gcc armedgetest.c -o armedgetest -lusb-1.0
and there we go, it compiled:
(networkx) tony@tony-magicbook:~/dev/robot/arm$ ls -l
total 24
-rwxrwxr-x 1 tony tony 16640 Jan 31 23:30 armedgetest
-rw-rw-r-- 1 tony tony 2468 Jan 31 23:17 armedgetest.c
It can now be executed:
(networkx) tony@tony-magicbook:~/dev/robot/arm$ ./armedgetest 00 00 01
Robot Arm not found
however, I am still waiting for those batteries to arrive before I can test this working.
along with the stereo cameras:
Now, combine that tech together and basically you get "more" than the £400 robot arm, for a lot cheaper but also re-cycling the existing kit and code that I had knocking around already.
The important part is - as I'm mis-using the car, basically just testing the very old camera module on the RPi 4 device, you can see that the car is actually quite some distance away.
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