5 replies to this topic

[moenia]

due to current problems to get the base-PCB, we're discussing, if we should order the PCB from local PCB-shops to start our project.

schematics, gerber-files, order-lists  etc. seem to be available within the git-tree below OpenPilot/hardware/Production/CopterControl, but we're not sure if this is a tested and working configuration, because there's no information available what is the problem with the last charge, which is not delivered to shops or end-users.

so, is there anybody here, who can either confirm, that the above directory contains a workiung configuration, or possibly has built up a working PCB with these files as source?

well, I've tried the contact-form at openpilot.org, but unfortunately didn't get a reply, so I'm trying here...

thanks for your help

moenia

[peabody124]

Those files should work.  However, if you are not used to doing SMD work then you might have a low yield.  The QFN16 packages are quite hard to get right.  I would highly suggest making a stencil too.  Also one of the components has had a fairly high fraction of parts out of spec (we're not naming the component to encourage a good relationship with the vendor) so be prepared to do some rework.

TL;DR: If you want the fun and challenges of making a board go nuts.  It will probably cost you 2x what we sell it for.  If you just want to get in the air quickly I would recommend ordering something else and trying to get a CC once you are flying.

[ANV]

1. http://forums.openpi...iting-for-a-cc/ - new batch is ready to dispatch.
2. http://forums.openpi...ию/page__st__20 - Gapey got some bare PCBs left after ordering for himself, he is not selling it soldered (license issue and unfair to Project).

[A*Morale]

The files work for sure ().
I used the dorkbot pcb service http://dorkbotpdx.org/wiki/pcb_order
Please keep in mind that building it yourself will cost around 120€ per board if you have to buy all the component needed.Add also the time needed to assemble them.
I didn't mention that obviously you should have got all the equipment needed to solder smd components and you should be well acquainted in handling and rework (it will be necessary if something doesn't work after build) surface mounted components.

[moenia]

first: many thanks for your answers.

because the delivery-date of the new batch wasn't clear and additionally it was not clear, if really everyone, who's interested in, will get a board, we've decided, to do it on our own...
after a while for ordering all necessary parts from various sellers, we've now built up four boards, which all seem to run well. (checked for now only with GCS via USB)

for those, who wants to go this way, too, here some infos:

what was necessary?
we've used the gerber-files to order the pcbs and got 8 boards (due to fabrication there're built up so much within one order). costs are 20€/each (sorry, we can't give any of this board away...)

we've used the orderlist from git directly for ordering at digikey and got the gyros from farnell. all together we've paid 300€ for components for four boards, 75€/each

the pcb-manufacturer added the stencils mentioned above, so we could use soldering paste.
some old pcbs built a frame and we use an old pci-card for pressing the paste through the stencil.

for asembling the PCB we used spiky tweezers and a 20x-stereoscope - I believe a 10x would be ok, too, but without it may not possible to place all components right...
for soldering we use hot-air, but we've to fix some junctions and bad solderings manually with soldering wick and a SMT-soldering-station.

for applying the paste onto the backside, we used a wodden plate, where we place a hole of 40mm, so the one-side-assembled and soldered pcb nearly fits despite the components on it but don't fell through.

to prevent detaching components while soldering the backside, we used scrunched aluminium-foil, to place the pcbs on.
a  check with a tempertaure-sensor shows temperatures up to 150°C on the back. maybe it works without the foil, but if not ...

after a visual check of the board we used a power supply with current limiter to check for short-circuit (but all went well)

to get the firmware on the board, we used a bought FTDI-serial-connector. a standard-serial could only be used, if the voltage-levels are changed to 5V! with a "make unbrick_coptercontrol" within the toolchain from git the bootloader gets on the chip and then you can either update the firmware with gcs or can use the JTAG-Interface to upload it.

well, you see: it is possible, but you'll need some infrastructure (stereoskope, SMT-soldering, ...) - but a good laboratory in high-schools or universities should have it and you should have at least some experience in soldering electronic components. NOTE: if something's going wrong, you should be able to handle this; a board does not work, you should be able to debug hardware, no warranty from anyone!

the complete boards may be more expensive, than getting them from a larger batch (if available), so you should check this before you start. (for us it was ok, because we need more than a single board and need them now and now we see, that we're not so much above the price of 95€ in europe for original copter_control. in other countries this may differ)

all this won't work without the really good develeopment of the copter_control-board and the great and comfortable tool-chain within the git-tree!!! many, many thanks to those, who've done this work!

as soon, as our project reaches next stage I'll try to report about.
sorry for any bad use of english, but it's not my native language. if you've questions, I'll try to answer them.

Edited by moenia, 22 February 2012 - 03:39 AM.

[dankers]

Well done Moenia, nice write up and a very similar process to what I use for building the test boards.