Shepard Hangout Aug 30, 2012
Attending
J, Jeremy, Ethan, Greg
Agenda
- Prep for Open Hardware Summit (time permitting)
Discussion
- J - Getting ready to hand off to Jeremy for DAQ integration.
- Be doing that at Club Cyberia in Indianapolis, IN.
- President has been contacted and responded positively to us coming and doing demo, test, development.
- J - Ethan’s suggestions helped.
- Used a ball bearing drawer guide.
- Direct Estes motor mount with copper T-fitting to exhaust ejection charge.
- Design covers 4x8x16 concrete block to hold the stand in place.
- There’s a hole in the upright where a string can go through so we can hang weights from a pulley to test the structure and DAQ setup.
- J - Has pulley set up to be installed, but thinks we can do better in future designs.
- Greg - In terms of architecture, what we came up with is a good level 1 kite design. What we were trying to do before was more of a level 2 kite.
- Jeremy - asked about the pully because the software allows a reading of the direct voltage. This is the first step to calibrating the system. and doing some additional developmental testing
- There are a couple other options that may be a good substitute if the FSR resistors are not robust enough
- Jeremy - How much budget is left?
- J - $65 spent on structural system already
- Jeremy - Is there anything that we can use for weight on the pulley setup to test accuracy, repeatability, hysteresis, etc.
- Dumbells, quarters, bolts, washers.
- Washers are easier to mount to a hanger.
- Try to engage Cyberia attendees with this part of testing the stand.
- Greg - A deadband at the lower end of the sensing range was why the ratchet setup was in an earlier design.
- Greg - Testing of those parameters:
- Accuracy: What accuracy can the FSR provide.
- Unless it’s completely abismal and we can’t get a decent approximation of the typical thrust curve, and somewhat accurate values, we should focus on quantifying the operation of the test stand.
- Repeatability: Has to be repeatable between firings. Going to be the biggest factor.
- Need to quantify the systems behavior, lag, usable range, sensitivity, etc.
- J - DAQ is complicated enough to be it’s own level 1 kite.
- Greg - Could just be a function of the knowledge and experience of the current team (sans Wilton).
- J- Doing a full NAR system would also go over the $200 budget just for one item.
- Jeremy - The thermocouple and signal conditioner, on their way.
- J - Can attach the thermocouple to the D & E size motors near the throat, other sizes will require modification of motor adapters.
- We need to secure the thermocouple with high temp tape like Kapton.
- J - Need a clear button, and a start/stop and save button for data CSVs.
- Have 2 charts for two different scales (force and temp).
- ACTION - Jeremy to bring thin, stiff tape for Saturday.
- Prep for Open Hardware Summit (time permitting)
- J - Wants to fire Shepard at OHS. Looked at where Eyebeam Studios is.
- Eyebeam is a building on a city block. There’s nowhere to fire Shepard.
- Greg - If they have a garage space that would work.
- J - They are more of a storefront.
- ACTION - J to email OHS organizers to find out if a firing can happen.
- Need poster and can show videos if we can’t fire. Taking a larger monitor for the laptop might work fine.
- Could also do calibration tests to show people how data is displayed and collected.
- ACTION - J to work with Bekah to come up with poster. 24” x 36” poster spec from OHS organizers.
- J will also bring extra materials about Mach 30 and ODE. Flyers, stickers, etc.
- Include a link to the Catalyst Club.
- Need to be specific with brochure about what people can go do to get involved.
- We need a ship-out date to get the stand to the OHS.
- Ship it cheap. On the order of a week. Summit is a 27, need to have the stand waiting on the 26th. Ship out by the 19th.
- Want video of the test stand firing with the characteristic curve before shipping.
- ACTION - J to put together 3 minute video with clips of Shepard operating. Use natural sound, no voice-over.