simple circuit will pay, please bid

[a.mlw.walker]

Hi guys. I am an amateur electronics hobbyist and I want to convert a recent project of mine to surface mount, however the company that will manufacture it are chargin loads for circuit board design - gerber files etc and wondered whether anyone here reckoned they would be able to do it and offer a fee for the job. I know this isnt normal forum procedure but its out of my depth really.
The circuit is simple. An avr mega1284p (in smt format) a bluetooth module (http://www.coolcomponents.co.uk/catalog/bluetooth-stereo-audio-module-p-743.html) - one of the pins of the avr outputs the audio using pwm...
an sd card (micro) and a cell battery powering everything. Will need caps etc for voltage regulator.
The bluetooth audio board requires 1.8v on one pin, Im not sure the best way to generate this, although maybe ok to just use a 1.8v reg

The most important thing is smallest size...
Please ask any more details that would be required

 

[GonzoEngineer]

If you can send me a schematic, and the approximate size, I will give you quote for a complete PC Board design. (I have been designing boards for over 40 years, and am semi retired. No overhead, so I can give you a good deal!)

 

[a.mlw.walker]

great

Thats great, I'll get you a schematic tomorrow, bit tired now. it wont be that professional, but it will show you what im affter.

If you dont mind I might need your advice on some of the points of the schematic/pcb when it comes to it

thanks

 

[GonzoEngineer]

Thats great, I'll get you a schematic tomorrow, bit tired now. it wont be that professional, but it will show you what im affter.

If you dont mind I might need your advice on some of the points of the schematic/pcb when it comes to it

thanks

No problem, happy to oblige. Check your PM's for my e-mail address.

 

[a.mlw.walker]

Hi Everyone, so I can't get hold of GonzoEngineer for some reason. I wondered if there was anyone else who might be able to help with this?
A

 

[CocaCola]

I would like to give Gonzo time to respond, but if he doesn't or for whatever reason backs out I might be interested in taking the project on...

I would need more input on requirements before committing though, most importantly I don't have time to verify 'your' design so I would request a final working design to work off of, no 'oops' I forgot this or that half way though or worse after you get the boards produced...

 

[a.mlw.walker]

Hi CocaCola.
Great, well I was speaking with Gonzo about a month ago about it, and then suddenly all email contact seemed to end.
I have the circuit design completed, however I do have a couple of questions that hopefully you will be able to answer reasonably quickly and wont cause a problem in the design.
The first is:
At the moment I am using PWM to output simple sounds (mono) out of a pin. This is attached to a 3.5mm female jack. It all works great when I plug headphones in, however I want to now send the sound via bluetooth. I have found this module:
http://www.coolcomponents.co.uk/cat...-p-743.html?osCsid=j90j5kqfegquksdbumahtmuqg5
which looks perfect. My question is though, and I believe I can, but I washoping you could confirm it, is can I just connect the ouput pin of my AVR to that and not have to edit anything else (codewise). Then connect the serial lines to this to be able to send it serial commands.

The second question is, I am currently using an SD card which requires between 2.8-3.3v which is perfect because my avr can be powred from this voltage. however that board above also needs 1.8v. I want to power it off two 1.5v cell bateries (3v in total) so is there a way I can drop this voltagte down to 1.8v? I cant find a voltage regulator that could do it, and I thought about possibly a diode or something however I think that would just drop the voltage by 0.7v...
lastly I've never had surface mount stuff made before, I am hoping that whoever manufacturs the bards for me will also populate them. What Im not sure of is generally whether I am expected to buy the parts, and hand them to the manufacturer, or they buy them. I am based in the UK so eitherway the parts used would need to come from a UK supplier.
Thanks

 

[CocaCola]

The quick and dirty way to drop the 3.3 volts is two diodes in series, it will get you about 1.9 and that appears to be a safe voltage for the module...

As for the module interface with the micro, it appears it should work, but you are really jumping the gun with a pc board design before you have tested anything (unless you have money to waste)... My advice is to get the parts, get the through hole version of the micro for ease and breadboard you entire circuit, debug and at least get working code and a FINAL circuit design before you even consider heading towards getting a pc board manufactured or designed... It's easy to add a resistor or cap or swap a pin on a breadboard model, not so easy on a final pc board design...

IMO you are jumping the gun on the pc board design, you need to focus your attention on the circuit design itself and also the firmware, and verify what might need changing or what not...

 

[a.mlw.walker]

In terms of the circuit, I already have the circuit on protoyping board and the code completely working. The only thing I dont currently have involved is the bluetooth module I linked.
As far as I can tell, you use AT style commands to program the bluetooth module into the mode you want, and then just connect the pins together.
I'll buy the bluetooth module and try to get it to do what i want on a breadboard, but the rest of the circuit is working well. If you go ahead with the design, I will send you pics of my current circuit. My aim was to make it as small as possible, which is why I want to go surface mount with it now because I want it even smaller. it currently runs off the through hole version of an ATmega1284.
If using two diodes will work, then Im happy with that tactic. seems a bit over kill to use a bigger voltage source, just so i can drop it down to 1.8v...

 

[CocaCola]

Like I stated before I don't want to step on Gonzo's toes so I would like to give him the benefit of the doubt... I'm certainly willing to explore this further if he bows out, but I would want you to test it fully including the bluetooth... There is no room for error when designing a pc board, if there is a missing trace, a wrong trace or a missing part the board won't work, or will need to be bashed to work... In a case like this as simply the guy doing the board layout based on your design, you have to understand I can't assume any liability unless it's clearly my mistake, an omission or design flaw in the original design has to be placed squarely on your end...

So for this reason I really emphasize that you have a final working and tested design and clearly relay that to me or whomever, I don't want to see you waste money paying to have an overpriced PC board drink coaster manufactured...

In regards to the size, instead of saying 'as small as possible' it's better for you to set a maximum size and work from that point...

 

[GonzoEngineer]

I am sorry I didn't get back to you......I have Chronic Myeloid Leukemia, and I am slipping backwards in spite of my medication.

Good luck with your project.

 

[CocaCola]

a.mlw.walker it appears Gonzo is stepping aside so if you would like to explore this further, feel free to contact me...