|
| Author |
Message |
|
PK
|
Post subject: Re: So what do people want from a "flight computer" ?  Posted: Thu Dec 16, 2010 8:55 pm |
|
Joined: Sun Jun 01, 2008 5:07 pm
Posts: 1684
Location: Perth
|
strud wrote: Scoop, I think it will be in the order of $100 You outrageous capitalist you! [/quote]
|
|
|
|
 |
|
strud
|
Post subject: Re: So what do people want from a "flight computer" ? Posted: Fri Dec 17, 2010 8:13 am |
|
Joined: Thu Oct 02, 2008 7:37 am
Posts: 692
Location: Hawkesbury Region, NSW
|
Well if the assembly and testing costs can be reduced (unlikley) the price could come down  Alternative approach is people put them together as kits, but we saw how well that went with the GPS project. CS
|
|
|
|
|
|
PK
|
Post subject: Re: So what do people want from a "flight computer" ? Posted: Fri Dec 17, 2010 8:34 am |
|
Joined: Sun Jun 01, 2008 5:07 pm
Posts: 1684
Location: Perth
|
strud wrote: Well if the assembly and testing costs can be reduced (unlikley) the price could come down A board redesign with all the components on one side would help. Batches of 10-20 would go together for about $6 a board on my manual setup. Not enough volume to justify the machine. QA costs drop when you set up for pogo pin test rigs. It's a a little bit of work up front, but... Well, you're the last person I need to lecture on the merits of automated testing in a production environment. Let's see how the digital baro sensors work out too. They're a little cheaper than the amp+strain guage setup we've been using and potentially more accurate. PK
|
|
|
|
|
|
rocket_troy
|
Post subject: Re: So what do people want from a "flight computer" ? Posted: Fri Dec 17, 2010 9:03 am |
|
Joined: Thu Oct 09, 2008 9:30 pm
Posts: 783
Location: Melbourne Australia
|
Quote: Alternative approach is people put them together as kits, but we saw how well that went with the GPS project. I vowed to never ever buy another kit that needs to be put together after that. I've probably purchased 6 or so kits like that in the past and I reckon I've had problems with every single &*@%$ one of them. TP
_________________
ERG #02
|
|
|
|
|
|
strud
|
Post subject: Re: So what do people want from a "flight computer" ? Posted: Fri Dec 17, 2010 9:27 am |
|
Joined: Thu Oct 02, 2008 7:37 am
Posts: 692
Location: Hawkesbury Region, NSW
|
|
The digital sensors aren't much cheaper I'd think than the baro sensor and amp I'm using and have limited altitude range (not a problem for most).
A simple low functionality altimeter could obviously be made more cheaply and a lot lower firmware developlement effort.
Troy that is why the kit thing is a false economy ie people may think they can save a little by putting it together themselves but 20 to 40 hours it takes them to finally make it work end up not being worth it.
CS
|
|
|
|
|
|
rocket_troy
|
Post subject: Re: So what do people want from a "flight computer" ? Posted: Fri Dec 17, 2010 9:37 am |
|
Joined: Thu Oct 09, 2008 9:30 pm
Posts: 783
Location: Melbourne Australia
|
Quote: Troy that is why the kit thing is a false economy ie people may think they can save a little by putting it together themselves but 20 to 40 hours it takes them to finally make it work end up not being worth it. I have no problem with the economics of the deal, it's that 10 or so hours of good quality pulling-ya-hair-out pure helpless frustration that's the real killer for me. TP
_________________
ERG #02
|
|
|
|
|
|
Scoop1261
|
Post subject: Re: So what do people want from a "flight computer" ? Posted: Fri Dec 17, 2010 9:44 am |
|
Joined: Sun May 06, 2007 9:29 pm
Posts: 1600
Location: Perth, Western Australia
|
rocket_troy wrote:
I have no problem with the economics of the deal, it's that 10 or so hours of good quality pulling-ya-hair-out pure helpless frustration that's the real killer for me.
Amen..... to that Brother! That... plus the fact.......I am just a LAZY SOB! 
_________________
Why Limit Yourself?
TRA #11080 - L3
MDRA #263
Prefect - Tripoli Western Australia
TAP Member
www.cgngroup.com.au
|
|
|
|
|
|
strud
|
Post subject: Re: So what do people want from a "flight computer" ? Posted: Fri Dec 17, 2010 11:31 am |
|
Joined: Thu Oct 02, 2008 7:37 am
Posts: 692
Location: Hawkesbury Region, NSW
|
The main point is to ensure that they are all tested properly and thoroughly to be confident they work as designed
|
|
|
|
|
|
strud
|
Post subject: Re: So what do people want from a "flight computer" ? Posted: Sat Dec 18, 2010 8:23 pm |
|
Joined: Thu Oct 02, 2008 7:37 am
Posts: 692
Location: Hawkesbury Region, NSW
|
1st board populated : Attachment:
New board_populated_top.jpg [ 243.54 KiB | Viewed 1323 times ]
Attachment:
New board_populated_bottom.jpg [ 240.19 KiB | Viewed 1323 times ]
Note the small board error on the 3rd FET (used as staging output or auxiliary function). Bit of a bummer but no big deal. Programming header shouldn't be required going forward since I'll program the pic with a bootloader prior to mounting. CS
|
|
|
|
|
|
PK
|
Post subject: Re: So what do people want from a "flight computer" ? Posted: Sat Dec 18, 2010 8:26 pm |
|
Joined: Sun Jun 01, 2008 5:07 pm
Posts: 1684
Location: Perth
|
|
|
|
|
|
strud
|
Post subject: Re: So what do people want from a "flight computer" ? Posted: Sat Dec 18, 2010 8:30 pm |
|
Joined: Thu Oct 02, 2008 7:37 am
Posts: 692
Location: Hawkesbury Region, NSW
|
|
Haven't used one before but willing to give it a try. Would obviously speed up assembly somewhat.
|
|
|
|
|
|
PK
|
Post subject: Re: So what do people want from a "flight computer" ? Posted: Sat Dec 18, 2010 8:38 pm |
|
Joined: Sun Jun 01, 2008 5:07 pm
Posts: 1684
Location: Perth
|
strud wrote: Haven't used one before but willing to give it a try. Would obviously speed up assembly somewhat. Your problem will be the components on both sides. You might get away with it. If you send me a dxf of the cream layers I'll cut you one. If only you had access to a laser cutter! Use the transparancies you do the artwork on. Offset to the inside by 0.15mm, cut them as a scan job (the deceleration into the corners cooks the plastic in vector mode), 0.05mm scan, 140mm/sec, about 20W and put something underneath it to stop reflections.. PK
|
|
|
|
|
|
PK
|
Post subject: Re: So what do people want from a "flight computer" ? Posted: Sat Dec 18, 2010 8:40 pm |
|
Joined: Sun Jun 01, 2008 5:07 pm
Posts: 1684
Location: Perth
|
strud wrote: Would obviously speed up assembly somewhat. Mikes up to about 25 uMads an hour, Including one board bug and hand soldering terminals... PK
|
|
|
|
|
|
strud
|
Post subject: Re: So what do people want from a "flight computer" ? Posted: Thu Dec 23, 2010 4:17 am |
|
Joined: Thu Oct 02, 2008 7:37 am
Posts: 692
Location: Hawkesbury Region, NSW
|
|
So I did some testing with the AD623A amplifier as an alternative to the INA122U.
Unfortunately it seems as though it has a lower drive capability (surprising) and when reading the datasheet it states that it is only rated to drive a 10k or higher load ! This meant that it is not suitable as a drop in replacement in my cct.
So, I'll be stating with the INA122U's. Good news is that their price seems to have dropped again for some reason....
First board seems to be functioning as expected. Will post some data from it shortly.
CS
|
|
|
|
|
|
strud
|
Post subject: Re: So what do people want from a "flight computer" ? Posted: Sat Jan 15, 2011 9:09 pm |
|
Joined: Thu Oct 02, 2008 7:37 am
Posts: 692
Location: Hawkesbury Region, NSW
|
Update : I have about 15 boards assembled so far and have got myself a little more organised. Still waiting on some terminal blocks to finish off most of them though. Good news is that this will be released onto Whooshtronics in a month or so once final testing is completed. There will be a detailed manual available but assistance and discussion regarding issues and 'new features' etc will stay on this forum. Here is a link to the draft version of the manual. http://www.members.optusnet.com.au/~cstrudwicke/Flight_Computer/Filght%20Computer%20Instruction%20Manual%20rev%200.5.pdfThere is a section still to be added regarding example installation.
|
|
|
|
|
|
|
