Hello All, If you’ve read the Ask Mr. Roboto column in the June 2007 issue of Servo Magazine. He did a real good write up on the use of the modules. I did see a pretty big Oops in there. He mentions that the SSC-32 does not have a +5vdc output so you need to wire up a regulator. Well the SSC-32 does in fact have a +5vdc output. And the BlueSMiRF can be connected to the SSC-32 with 2 off the shelf cables, with a slight modification of course. We are currently developing a full tutorial for the BRAT and the SEQ program. But for now you can view this diagram to get it going.
Because Remote Control can be generalized as joysticks and a receiver such as a RC car or airplane setup, or a Sony Playstation style controller. Wireless can be thought of as data communications, weather it’s WiFi or Bluetooth. I thought they were different enough to have separate sections.
As to using the Blue SMiRF with the SSC-32, I have to say that I was quite impressed with how quick and easy it was to get it rolling on the “Walking blues” project.
I wanted to go wireless, since a serial cable would tend to drag the bot around from the top while it was trying to balance and walk. I got the Blue SMiRF (RP-SMA version), and didn’t do much with it for a while, since I was reluctant to start anything new which could potentially require a bit of sitting down and troubleshooting it before getting it to work properly. As it turns out, that was a needless worry - I bashed together the cable (two 3-pin header shells glued together), plugged it in, and lit it up on the first try. The Bluetooth dongle I had (not the one offered by Sparkfun) saw it, recognized it, and connected to it with no issues, and suddenly I was running wireless. It really is a transparent cable-replacement, with no tweaking necessary out of the box. Sure you can tinker with stuff after you connect, but for basic connectivity, I was pleasantly surprised to see that it was about as “plug and play” as it gets.
I don’t have one showing the onscreen process of connecting, but I do have this Link] to the YouTube video of Walking Blues doing its stuff. The flashing green LED at the beginning indicates that it’s powered on and waiting for a connection. If you turn up the volume, you can hear me double-click on my notebook’s mouse button to connect, at which point, the green LED extinguishes, and the red one illuminates solid, indicating an active connection. Everything after that is being fed to the bot via the Bluetooth virtual serial port, as though it was connected with a cable. You can hear me click the “play” button in SEQ, which steps it through the sequence for park, stand, three forward steps, stand, and park. Then I turn off the bot. A second or two after that, the bluetooth dongle on the notebook realizes that it’s lost the other end of the link, de-allocates the COM port, and drops its end of the connection.
Heh. No, that domain is really just an “image dump” - I’ve been using it as a file host, in order to clean up the access statistics for my other domains. I have a few “go nowhere” pages like that, as I have some friends who enjoy digging around in subdirectories to see if they can shake anything loose.
I’ve been working on my actual site, but not fast enough. Unfortunately, I don’t currently have any up-to-date robotics information on the web, other than the photo and video posted above.
I didn’t know that you could use the A/D port to source current to another device. With that said, this is a whole lot easier to do.
Now I have been using this with my 17 servo biped, and it works quite well.
Though Jim was able to get 50 feet with the ceramic antenna version of the BlueSMiRF, I wasn’t able to come close to that. I had to use the duck antenna version to get the better range. This was not the fault of the BlueSMiRF, but the USB Bluetooth dongle since it doesn’t have the output power to transmit the longer distances reliably.
The key is reliable communication, especially with a 17 servo biped.
What happens is that communication is lost for a monent, then the data is delayed. With the PC tranmitting data at a specific rate and assuming the robot is processing it properly, a delay in the communication causes the robot to get out of sync and bad things begin to happen. The blueSMiRF does do some buffering, and will transmit the data, but it the signa; loss is too long, the delay will cause the robot to get out of sync, or in many casses, the BlueSMiRF will time out and the signal is lost completely, and you will have to reconnet to the device.
Spend the extra dollars and get the duck antenna version. This will save you a lot of headaches.
When your bot looses sync. does it potentially cause the servos to move past its limmits? or does it just case it to buckle and fall over having a servo seizure?
We tested the range simply by moving the robot and the laptop to opposite ends of the building. The “connected” dotted line in the BlueSoleil program, and the red LED on the BleuSMiRF stayed on steady. However today, just to make extra sure, we did a more “real” test and had the BRAT walking around the office from one end to the other. The range really is more than 50’.
We are currently developing a full tutorial for the BRAT and the SEQ program. But for now you can view this diagram to get it going.
I stopped upgrading at version 8. I can do everything I need with it.
