|Surveyor Robotics Journal|
Sat, 29 Dec 2007
Python version of SRV1Console
We have posted a Python version of the SRV1Console to http://www.surveyor.com/blackfin/.
pySRV1Console is similar in function to the java-based SRV1Console, though the code is more easily extended. The basic SRV-1 controls are supported, and though not yet fully implemented, there are hooks for firmware uploads, user flash editing, and image processing functions which should be operational soon.
We welcome SRV-1 user extensions to this code base !
Fri, 28 Dec 2007
SRV-1 Lunar Lander ?
Excellent coverage today on CNBC for the Team FREDNET entry in the Google Lunar X Prize competition, using an SRV-1 Blackfin robot to demonstrate remote control and video access of a lunar lander via the internet. Nice work by SRV-1 owner Kevin Boyd at University of Michigan to support the Team FREDNET effort.
Click on the image below to access the CNBC feed -
If you are unable to access CNBC, we have archived a Quicktime version on our website - http://www.surveyor.com/images/lunar-lander.mov
Thu, 27 Dec 2007
SRV-1 antenna issue
An observant SRV-1 customer noticed some signal strength issues with his robot at longer range, and then asked why neither the 3db antenna nor the SMA bulkhead connector on the SRV-1 seemed to have a center pin. And he was right - there is no center pin, and therefore no connection between the antenna cable and the antenna.
One would expect that we might have noticed this in the 1.5 months the new SRV-1 has been shipping, but we didn't - we configure and test the WLAN radio modules and robots without antennas, as the radio module has pretty good range without one. We only add the antenna to the shipping box as a final step before taping things shut.
There is an easy fix. The pin diameter is approximately the same as 18 gauge wire (approx 0.9mm or 0.035"), and a 0.250" - 0.300" (6.5mm - 7.5mm) length of 18 gauge solid copper wire seems to work nicely. At the hardware store, they refer to this 18 gauge wire as "Bell wire" or "telephone wire".
The only trick is to straighten the wire before insertion and make certain the wire end isn't flattened where it has been cut, but this can be corrected with pliers.
We contacted the antenna manufacturer and learned that both the SMA bulkhead connector and the antenna can be ordered with the center pin, but we had neither, and nobody flagged this before. In the future, we will order the SMA connectors with pins, and until the new cables arrive, we will add a pin to the antenna for new shipments.
By all reports, this fix is working well. We are somewhat embarrassed to have missed this, but are at least glad that our users are paying attention.
Fri, 21 Dec 2007
new lenses, new combo radio/motor-control board
We just received a shipment of add-on lenses for the SRV-1 Blackfin Camera Board. The standard lens has a 6.5mm focal length with f3.2 aperture and approx 60-degree field of view. The new lenses are wide angle - one is a 3.6mm focal length with f2.0 aperture and approx 90-degree field of view, and the other is a fish-eye with 2.2mm focal length, f2.5 aperture, and approx 120-degree field of view.
We are going to offer the 3.6mm and 2.2mm lenses as an add-on option with the camera boards and robot for $29 for the lens pair - this will be added to the shopping cart in the next 1-2 days.
Here are some images captured by the robot from the same position, in order of 6.5mm, 3.6mm and 2.2mm. Note some reflection in the pictures because they are shot through a window, and there's not much light. The 2.2mm has a lot of fish-eye distortion, but a nice wide field of view. The 3.6mm has some fish-eye, but isn't too noticeable except with close objects. The 6.5mm is pretty linear.
Also, I wanted to mention that we have a new board that combines the Matchport WLAN radio with the motor control and laser driver circuit. By combining these functions into a single board, we reduce the robot height be 9/16" (15mm) and simplify the assembly. The new board won't have the back-emf circuit, but it will add support for the 2nd Matchport UART, and we're looking at alternative (more accurate) speed measurement approach using optical flow. We will probably start to switch production over to these new boards in 2-3 weeks. The motor control board with back-emf will still be available as an option, but the standard configuration will ship with the combo board.
Here are some photos of the combo board setup -
Sun, 16 Dec 2007
SRV-1 firmware update - test version
A test version of the latest SRV-1 Blackfin firmware is now available from http://www.surveyor.com/blackfin/ - look for srv-blackfin-121607.zip. Release notes are found here. Basic image processing functions have been added, and the code has been substantially restructured for easier maintenance and extension, thanks mainly to the Transterpreter development group - http://www.transterpreter.org - who are in process of porting the Transterpreter Virtual Machine and OccamPi programming language to the SRV-1 Blackfin.
Also worth noting is a new version of ldr-utils for Linux, also available from the SRV-1 Blackfin download page, which now support the Blackfin UART boot mode via the Matchport WLAN connection. This is significant for users without JTAG who might clobber the boot loader image of the SRV-1 firmware and need a way to recover. We don't yet have a corresponding version of ldr.exe for Windows, but will be happy to post a working version if anyone out there can do the port.
Speaking of JTAG, we strongly encourage users who are planning any significant code development on the Blackfin to consider getting a JTAG cable if they don't already have one - JTAG is a huge timesaver in loading and debugging new code, and is well worth the investment. Our recommendation is the ICEbear from www.section5.ch, which works with GNU gdb and interfaces via USB. There are also some low-cost JTAG cables with parallel printer port interfaces, but none of our computers have parallel ports anymore, so we haven't tested these.