The weather again chose not to cooperate this year for our regular venture down to Black Rock for the UW rocketry class. However instead of cancelling altogether, we were able to adjust our plans and visit a launch site in Brothers, OR. It was a shorter trip, just over a long weekend, but was neat to see a new area.
The group was again smaller this year because the late schedule put the trip into the next quarter’s classes, but still a decent turnout. A number of good flights were had, though recovery was hampered by the scrubland, in comparison to the perfectly flat and open playa we usually have at Black Rock.
I end up doing a number of PCB designs for various projects. Most are small one offs that aren’t a huge problem to assemble by hand, but there are instances where I have multiple to build, or large boards with hundreds of components. In these cases it can take a number of hours of tedious, exacting, labor to place all the parts. Especially in the case of needing multiple, I found myself putting off the work and letting those projects languish.
In light of that, I decided to purchase an open source prototyping pick and place machine, specifically the LitePlacer. This machine comes as a kit, and after assembly and calibration, can place components on boards automatically. It’s not as fast as a professional production pick and place machine, but it also doesn’t cost a million dollars and I can set it up and let it run while I work on other things.
I found the kit instructions quite good, and quickly had the mechanical build completed.
Next was the electrical build which included wiring up all the motors, switches, and other bits to the control board. Then would be calibration and testing.
And finally, placement of the first board!
Since then I’ve placed a few much larger boards with hundreds of components, and I’m quite pleased with how the machine runs. I still need to do a bit of work in terms of the optical recognition on black and clear tapes, but overall I’m pleased to be able to offload this work a bit.
While it’s not particularly new or novel, I’ve long been interested in setting up an Oscilloscope Clock with one of the various kits that have been available for some time. Over the holidays one of the gifts from my family was based on this, and encouraged me to go further to build a clock around a raw CRT tube, rather than just something that interfaces with an existing oscilloscope.
Soon enough I had found a real gem of a tube with a helical PDA, which I thought was just gorgeous.
The tube is a 3BFP1, which is a 3 inch, flat face, with a standard green phosphor like you’d see on an oscilloscope.
Next I needed a setup to drive the tube, which needs a number of various high voltage sources to drive it. I didn’t particularly feel like jumping into designing those circuits myself at the moment, so I found a kit from a fellow in the UK which handled the various power supply needs, and included a very smooth clock display board as well at http://www.sgitheach.org.uk/scope3.html
Soon enough the kit was in hand, and thus began a few evenings of soldering the kit together.
At this point I’ve got power to the tube, and first light. It’s still not well focused, but good progress. Next I move onto building the clock and signal amplifier boards, which will let me actually try displaying something on the tube.
Finally some more work on getting the voltages tweaked to improve brightness and focus, and I had a display I was happy with.
Not perfect, but there may also still be a little room for improvement when it all gets built into an enclosure when I add magnetic shielding. Next I started working on a prototype layout for all the components before I commit to things.
This is how it stands today. I think I’m happy with this layout, so now as I have the time, I’ll make a base out of some wood that’s a bit nicer than plywood, and work on an acrylic enclosure to keep fingers out of the high voltage bits, but still allow the tube to be on display.
After having to cancel the trip last year due to poor weather conditions, we were able to make the trip down again this year to the Black Rock desert in the northwest corner of Nevada.
We had a bit of a smaller group than usual due to having to schedule the trip later than typical, but still a number of good launches, as well as an afternoon visit up to the Soldier Meadows hot springs north of the playa.
A bit ago I posted about setting up an RPi with cellular connectivity which could be used for any number of ideas. One I mentioned was a remote webcam.
I took the basic setup I had shown before, and attached a small solar panel, sealed it in a watertight enclosure, and placed it on some national forest land adjoining a nearby mountain pass.
I used a small arduino board and a mosfet to control power to the RPi. It woke up once an hour to take a photo and upload some telemetry and a thumbnail to my server over the cell connection. If there was a thumbnail I wanted a better look at, or to establish a ssh connection for admin, there were command files I could leave in place on the server that would instruct the RPi to perform additional actions before going back to sleep.
Every so often as the SD card got full, I would drive up and park nearby, and download the full size files over wifi connected directly to the RPi.
Unfortunately, in summer the unit stopped responding and had to be retrieved. Once I was able to get it home and look at it, I found the RPi’s SD card had died, so it couldn’t boot up to do anything. I’m usually careful to buy quality name brand SD cards, but it appears this time one slipped through and lead to the failure.