Author Topic: Wanted: someone to choose parts and design PCB  (Read 2629 times)

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Offline rthorntn

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Wanted: someone to choose parts and design PCB
« on: August 02, 2018, 04:50:07 am »

I'm a bit of a newbie thats wants to build something.

I would need somebody to choose the parts, design the board and possibly write the code.

I understand most of what I want to do and I could cobble together lots of breakout boards from aliexpress, code from google and I'm pretty sure it would work (its a PID loop) but I want a professional PCB designed.

Below are my thoughts:

Circular PCB mainboard 20cm diameter with a 50mm hole in the centre (The 48mm [~2mm kerf] centre hole PCB used for the remote rotary encoder and 12 x RGB LED PCB)

Should be designed with serviceability and community open-source manufacture in mind

Extended temperature range

Heat dissipation should be factored in


Board input is 48V DC, output rails:

48V 10A (heater)
12V 3A (fans and MOSFET drive)
5V or 3.3V 1A (MCU's)

Mainboard has two MCU's

Primary MCU connections:

- Heartbeat output
- Onboard FTDI USB-Serial
- 3 x temperature inputs for thermistor or thermocouple
- 3 x fan outputs, each 12v 1A with speed control and reverse polarity function, onboard motor drivers
- 1 x heater output, onboard power MOSFET, 48v 10A, needs to be spec'd to run for 15 minutes constant
- Remote Rotary encoder and 12 x RGB LED PCB I/O

Secondary MCU connections

- Heartbeat input
- Remote relay board connector 5v logic

The primary MCU's main function is to run a PID loop
The secondary MCU's main function is to power off the system if the primary MCU stops responding (watchdog), maybe it also connected to an onboard thermistor and maybe its operating temperature range is higher than the primary MCU

Being a newbie I have no idea what something like this would cost to design.

Thanks for looking.


Online blueskull

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Re: Wanted: someone to choose parts and design PCB
« Reply #1 on: August 02, 2018, 05:06:41 am »
I don't have time to do this, however, I can give you an estimate based on my experience:

1. Research: 10 hrs
2. PCB library and schematics: 5 hrs
3. PCB layout: 5 hrs
4. PCB fine tune and optimization: 5 hrs
5. Embedded firmware: 10 hrs+unknown time for debugging
6. Computer GUI: 5 hrs (a crude interface)
7. Prototyping and small batch mfg for 10 units: 20 hrs
8. System level debugging: 10 hrs

Bottom line: 70 hrs, or ~$7k US for average professional consultants.
With parts and documentation and others, I would expect $10k minimum to get this thing rolled out.

Alternatively, you can try to find university students, maybe from some design clubs or from some maker spaces.
They usually cost $15 per hour for BS students or $20 per hour for graduate students.
Since you can't give them credit hours, I would expect them to charge you more than they charge the university, but still $30 should be more than enough.

With undergrad students, you want to pay by task, not pay by hours. This is extremely important. Get 2 kids, each for a task (hardware, firmware+software), give each $1500, pray and see what they can deliver.
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Online rx8pilot

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Re: Wanted: someone to choose parts and design PCB
« Reply #2 on: August 02, 2018, 05:30:36 am »
However much you think it will cost.... it will be more. Count on it. Budget for it.

I have seen a lot of projects that are almost finished.... but the money/time dry up before the finish line.

Estimating the cost of a project is easy. Estimating a project accurately is quite difficult.

Short and misplld from my mobile......

Factory400 - the worlds smallest factory.
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Offline radiokot

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Re: Wanted: someone to choose parts and design PCB
« Reply #3 on: August 02, 2018, 09:01:29 am »
Hi rthorntn.

I wrote in a personal message.

Best Regards,

Offline julianhigginson

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Re: Wanted: someone to choose parts and design PCB
« Reply #4 on: August 02, 2018, 09:37:37 pm »
Easily 70 hours.

Probably a fair bit more if you want good technical documentation beyond just the schematic and fabrication/assembly files that allows makers to work on the board, and you want to limit parts selection to through hole or large SMT and avoid modern simple motor control ICs they also limit peak current, etc.

And more again, if you want the firmware polished enough and fully commented for public release and reuse by makers..

I expect you won't need a 2nd microcontroller.  But that depends on more details around what the watchdog behaviour needs to be (and what the device is, in terms of trust the user is exposed to in using it)

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