Monday, 4 July 2011

Test stand and programing frustration

I worked on the test stand for most of yesterday. All the plumbing on the fuel side is pretty much done. I I am waiting for a few NPT to BSP adapters but once they are installed the fuel side will be done. The line looks like copper but its actually "bundy line" which is just mild steel with a coating. Copper is much much easier to work with but its also costs much much much more. I started using a pipe bender but it could only bend with a radius of 5cm (as it was designed for larger pipe) and i ended up just using a vice and my hands for most of the bends. I kinked it a few times initally start but once i learned its tolerances for bending things sped up.

I am waiting for two solenoids then i can start the oxidizer side. Originally i was planing on having hand operated ball valves to fill the oxidizer tank, but after pressure testing the tanks (and having a failure) i thought, i really don't want to be near that when its filled. So with the two extra solenoids the procedure will be close fill and vent, open nitrous bottle, leave, open vent, open fill for hoverer much oxidizer i want, close fill, close vent. I also need to thoroughly degrease all components as the ball valves come filled with grease and i was pressure testing the tanks with oil.

I also added a few steel plates to hold the pump, electronics and main propellant valves.

 After that, and today i have been working on programing and have been getting frustrated with the lack of progress. The main problem i am having is with data types.

There are two parts to the control system. A ardwino on the test stand which controls test stand functions and program which runs on a computer connected wireless via serial which controls the ardwino.  I have invented a protocol for communication which is so far only one way (to ardwino) which is simply  to send a string with one letter and 3 numbers. The letter is the device to controll and the number is its value. So 'i001' is igniter to 1 (which is on). It seems simple enough but just getting the string and separating it into its command and value components took quite a while, although the ardwino side is done now. I kept having wired issues where i would get the last command only when i sent a new one. Te other problem i was having is that "strings" and "chars" are not compatable (which it took several hours to figure out). Now i am now working on the computer side. Recently someone was talkign on arocket about writing a trajectory simulation and they said if you assume its easy you wont be able to to it. I think that this is true for alot of things. If you assume something is going to be trivial your in a mind set where you get frustrated when things go wrong or you dont understand something, and this is exactelly what i have been doing.

No comments:

Post a Comment