Project price estimation - image scanner

[gaminn]

Hi,
I'm a HW & FW & SW freelancer. I'm working on a card scanner and I would like to ask you, how much would you ask to design this scanner. This are requirements:

- double sided image scanner for credit card sized cards. User inserts 2 1/8" wide card into slot of the scanner, wheels/rollers powered by a motor moves the card between two contact image sensors (CIS, 300 dpi reolution), the image is being sent to control PC during scanning process. When the scanning process finishes (should take less than 2 seconds), the card stops inside the scanner, waiting for control PC to process the image data. Then PC sends command to release the card - motor reverses and the scanner moves the card back into the slot where user removes the card from the scanner.
- my job: electronics & firmware with analog front end, optical sensors to detect card, motor control, communication protocol (USB) and some basic software on PC to demonstrate and test the scanner. Mechanical part (CIS placement, rollers/wheels, slot, ...) is not my job.
- I pay for electronic components and PCBs during development, I use my own equipment - scope, power supplies, multimeters, soldering station, ...
- USB is used to power the scanner including motor. The PCB can have 2 USB connector to supply enough power for both scanner electronics and motor.
- CIS calibration procedure must be implemented to achieve decent image quality (on PC the image is processed using OCR; a note: OCR is not my job, I just send image data from scanner and receive them on PC and provide some basic interface to command the scanner from PC and to signal a status of the scanner on PC)
- measures against attempts of inserting too long or too short card must be implemented. The card can stuck inside the scanner because it can have some defects. When this happens, the scanner waits for somebody to manually release the card.
- cost of the electronics (assembled PCB, motor, optical sensors) should be 40 - 50 USD @ quantity 100. CIS cost is not included in the price.
- final product of the project is assembled PCB and demo software for Windows. Connector placement and shape of the PCB is specified by customer.

How much $$$ would you ask for this project? I'm just curious about my price estimation hopefully being similar to more experienced designers. I'm aware that cost of labour is different at different places around the world.

This is one of the prototypes and scanned image to see what the acceptable quality is. And demo app for PC.

[OwO]

$10000

[JVR]

If those are the only requirements you have, 100000€ should do it.

If you somehow have a proper requirement specification that will limit the scope of the project, then it depends on future volume, and whether you will be the OEM or not.

[gaminn]

If you somehow have a proper requirement specification that will limit the scope of the project, then it depends on future volume, and whether you will be the OEM or not.

Thanks for your estimation.

I'm not OEM, customer will manufacture it. I give him all source code and design files. And one or two working PCBs together with demo software which he will test to confirm the requirements were fulfilled or not.

[JVR]

Then you will need to up your cost a bit, as once you hand them the design files, they will come back and expect you to support "small changes".

Is that the only requirement you have? And what price were you thinking?

Honestly, if it was a POC, I'd probably charge in the range of 8000€-15000€, depending on their needs and time pressures.

[gaminn]

Future changes, even small ones, are paid, the customer knows it.

I will write my price here tomorrow.

POC? Proof of concept? No, this goes to production soon. So, 100 000 € or 8 000 - 15 000 €. That's quite a difference.

[JVR]

100k is taking the piss, its meant to show that with so few requirements, I wont touch the job.

[gaminn]

Not sure what else one needs to know about this project. I added some pictures to ilustrate what customer expects to be delivered.

[Domagoj T]

Having never worked with contact image sensors, do they work properly only in actual contact, or do they have a usable range (a few mm) where they maintain sharp image?

[gaminn]

Image is sharp only when there is direct contact or max 0.3 mm between object and sensor.

[JVR]

Not sure what else one needs to know about this project. I added some pictures to ilustrate what customer expects to be delivered.

Uhm...
Voltage Ranges / PSU capability?
Transient Environment?
Temperature range?
Humidity?
Expected operational life?
Edge case behaviour?
Error detection and resolution?
Logging?
Physical Security?
Software Security?
Tamper Proofness?
Spoofing?
Physical I/O control spec?
Motor type, spec, gearing, stall current?
What is "too long or too short" for the card
Length of the USB cable?
Optical environment?


That list goes on for long.
Requirements are not just another shitty piece of admin, they are the document where you and the client make sure that there are no misunderstandings as to the problem, and the capabilities of the solution. And in those requirements lies the rub of making a profit, or losing your shirt.

Have you done this sort of project before? What is your experience level with building products from scratch?

[gaminn]

OK, I forgot to mention this will be used in normal clean room. Security? Not important. Just enable MCU's flash read back protection, nothing else specified. 4 years lifetime but it is expected this is mainly limited by the motor. Some ESD immunity is good (mainly on USB), the electronics is closed in metal enclosure, inaccessible to ESD strike. Motor is DC, 1 A motor driver si OK. Error detection - too long is 7" and too short is 2" There should be no other errors - the customer will test the scanner and if it won't scan the card than you will fix the scanner I/O specification is up to you, just get the data to and from PC via USB.

I ask here because I finished the project with a loss (invested more time than I expected). I know exactly why this happened - I idealized the project, expected that everything will work like a charm and underestimated the time needed. But in reality, there are bugs in software libraries you use, you make mistakes, you spent more time with some parts of the projects, because you realize that something can be done better... Here, I wanted to confirm if my rate was low, normal or high. If low - then, in future projects, I will be more expensive for sure. If normal or high - then I'm not a good designer.

[nsrmagazin]

4000 EUR is possible, but thats only the materials.

[gaminn]

Thanks. In my case I invested much much more of my time than materials. I expect this to be similar for anyone else.

[JVR]

There should be no other errors

Never in your life say those words again. A user WILL find an error, somewhere somehow.

I know exactly why this happened - I idealized the project, expected that everything will work like a charm and underestimated the time needed.

If this comes across as me being an asshole, I apologize, as that is not the intent. The above is wrong. Due to not having cemented goalposts with the client, you could never get to the "good enough" point, and you never will, we are engineers, we strive for perfection. Remember the adage that perfection is the enemy of good enough.

Please share your numbers with us, including time taken to complete, I'd also love to know how my earlier projection fits in there.

[gaminn]

Never in your life say those words again. A user WILL find an error, somewhere somehow.

Of course there will be errors. And they will be fixed. If the error is found during testing period, you fix them for free. If they are found later, you are paid for it.

If this comes across as me being an asshole, I apologize, as that is not the intent. The above is wrong. Due to not having cemented goalposts with the client, you could never get to the "good enough" point, and you never will, we are engineers, we strive for perfection. Remember the adage that perfection is the enemy of good enough.

I'm chronic time underestimator And I also design almost perfect electronic devices. That is bad combination.

Please share your numbers with us, including time taken to complete, I'd also love to know how my earlier projection fits in there.

Not now, I really want to see other's unbiased price estimations.

[Tomorokoshi]

Unclear from the specifications so far:
1. Is the transport mechanism off-the-shelf and already designed and tested, or:
2. Does it have to be designed?
3. Who is designing it?
4. Has it been prototyped?
5. What are the requirements?

[coppercone2]

how long did it take you develop * your salary and how much do the parts cost * random number you feel you can get away with * another number you think you can get away with

realistically you look at how much work you got in a year, where you want your salary to be and how much time the project occupied.

[coppercone2]

If you somehow have a proper requirement specification that will limit the scope of the project, then it depends on future volume, and whether you will be the OEM or not.

Thanks for your estimation.

I'm not OEM, customer will manufacture it. I give him all source code and design files. And one or two working PCBs together with demo software which he will test to confirm the requirements were fulfilled or not.

make a prototype and put in a box that kinda has the idea right so you look good

screw it to a piece of wood so you don't get screwed by some guy complaining about chassis manufacturing costs etc. they won't act so high and mighty for putting your guys into a plastic box then. It will just be a plastic box and not a systems engineering challenge if you already put it into a crate for him. Otherwise he might say your price is unreasonable because he needs to hire someone at 80$ an hour to shorten a ribbon cable or something. Instead he might pay someone like 40$ an hour to 'change the way this box looks'.

[nctnico]

The best thing to do is break a project down in small tasks like selecting components, creating the schematic, doing the layout, building the prototype, testing, setting up the microcontroller, writing low level driver, testing the software, etc, etc. I usually do this by a granularity of half a day (=4 hours). Then add all the numbers and there is the number of hours you'll likely spend on it. When working on the project keep track of the number of hours and make sure not to get carried away making things much nicer than necessary.

[gaminn]

Unclear from the specifications so far:
1. Is the transport mechanism off-the-shelf and already designed and tested, or:
2. Does it have to be designed?
3. Who is designing it?
4. Has it been prototyped?
5. What are the requirements?

The transport mechanism is designed by someone else. I got a prototype of the mechanism to have something to try the electronics with.

[gaminn]

not to get carried away making things much nicer than necessary.

This sometimes happens. And also it often happens that my time estimation is bad. I have to multiply by 1.5 to get realistic time estimation for this project. Not sure if my planning or design skills are bad.

[gaminn]

Hey guys, give me some numbers. I will average them and from statistical point of view, we should get the correct number. You have all information I had when I started the project.

[james_s]

Is there a reason you can't use an off the shelf sheet feed scanner? They are available in double sided format, even small ones for scanning business cards and ID cards. Cheap and ready to go.

[gaminn]

The scanner is built in a ATM like machine. The client doesn't want to adapt his machine to new scanner, when old scanner is discontinued. There is also need for stopping the card inside the machine until the PC processes the card and maybe some other specific needs.