LU2MI2 build log: July 11th, 2013
July 12, 2013
As noted elsewhere I had to start something new to add updates to this project and from now on it will be in the form of blogs (it's about time, huh!). To summarize the project's status, things were going well until I went to test all the subsystems together on the actual chassis. I had forgotten to breadboard test the 3.7g servo at the 3.3V I was going to supply it with and it turns out it hated it. I have since acquired some of TI's sn74lvc1g34 buffer/line drivers that operate at <5V and made changes to the PCB to accomodate it. The new PCB design still needs to be sent to the fab house.
In the meantime I thought I'd include the pics I've taken after the last point that the project page stopped accepting updates.
Ditched the temporary harnesses and wired up all the permanent ones. Ready to test the fit and execution.
Servo on the CtC acrylic "bulkhead shield" and attached to the standoffs.
The charging and programming jack with hotglue strain reliefs. Correctly wired this time around so there was no burny smells when tested :)
Jacks are hotglued into place (yes I know, less than optimal method). Harnesses ready for connections.
The PCB stuffed into the gap with all the snakey wiring hooked up to their respective connectors. The lengths of wire were necessary to have enough play to plug and unplug all the connectors. I was surprised anything worked at all. In fact it all worked fine except for the aforementioned servo! All the connectors can be accessed (relatively) easily without disassembly except for the programming jumper which requires the removal of the PCB. Hopefully I won't need to fiddle with that too much as the project end approaches because I'm still not sure how to afix the circuit board to the bot and still be able to remove it easily. There isn't really any room to add any fasteners or velcro or such things. Hotglue again? Probably...
The head with the 555 circuit, low-voltage LED, and phototransistor circuit board. I had to ditch the fan-looking speaker (as hoff put it) in favor of a thinner and pricier speaker. The speaker was just too bulky and it blocked the mounting area for the tube that will attach the servo to the head. The new speaker stays put with its magnetism only but I doubt I will rely on that in the end. The phototransistor and RGB LED are tacked into place with dabs of hotglue. The yellow undervoltage LED is not in place as it seemed inconsequential compared to the rest of the problems I was having.
The 100uF cap was also bumping into the components on the inside of the bot. It will be replaced with a 0805 sized version that will conveniently straddle the solder pads nicely. Much more expensive than its taller PTH electrolytic cousin pictured here, however. This bot has eaten up more $$$ than I expected so it's just a drop in the robo-bucket.
I would like to say that this robot will be done sooner than later but I'd hate to have Vader tell me that, "The Emperor does not share your optimistic appraisal of the situation," and then choke me out. I will instead go with the statement that LU2MI2 is still progressing. Erratically, but progressing.