I'm sure you have all been there, you design something, with no real intention to sell them but for a personal need and you get someone that wants one, you say sure, add a few pennies for the trouble of you putting it together and they baulk at the cost.
So, to add some "meat" to my post, I have a Nexus dashcam that has some fancy parking mode, but it means that it has to be connected to a permanent live in the car, the dashcam says it'll turn off if the battery voltage gets to 11.2V, that is far too low for my liking, so I decided to put together a simple PCB that has a voltage divider a PIC12 and a relay to turn off the power if the voltage gets to 12V and stays off until it sees a voltage above 12.6V, it has a fuse and TVS as well as a few jelly bean components, and for my purposes it works well, I am planning for V2 to use a MOSFET for the switching instead of a relay and have a MOSFET for reverse polarity protection, the PIC ADC is good enough for what I need and the measurement between the ADC and multimeter is close enough for me, I store the values for OFF and ON in E2 so I can change them via UART if I need to, I used a Chinese PCB manufacturer and have 5 PCB's made and have a few spare as I used 3 of them for my own use, and the components I just bought from Farnell here in the UK, so they are not the cheapest but they were readily available and delivered within a few days, so the individual cost is around £25-£30 for raw component cost, I also found some small plastic boxes at a local hardware store that fitted quite well.
Now I was showing a friend the dashcam itself as it has a connection for a rear camera too and I was explaining to him about how I wired it it and how the parking mode worked and the conversation came around to my little "protection" box, and he asked if I would be willing to make one for him, and I said sure, i'll let you have one for the cost of the parts plus a bit of soldering / assembly time, he said that was fair and i'd let him know the actual price I would charge him.
I said I'd let him have one and help him install it but as I got the parts from a UK supplier it would be around £35, which I thought £5 to solder and assemble it was cheap, mostly SMT in anycase, and takes about 20 - 30 mins with programming / testing of the PIC. I hadn't heard anything back from him then he messages me this afternoon saying he's found one on eBay for £10 (from China) that is sold as a battery protector for a car and he has bought one so he doesn't need mine, I looked at the link he sent and it cuts the voltage at 11.5V which I think is too low still, and I looked at the relay (it comes bare board not boxed) and the one I used on mine draws 16mA as 12V the one on the Chinese one pulls 80mA at 12V, no fuse, no TVS and what I can only assume is a comparator, so I just said to him "Good luck", it doesn't bother me that he bought the Chinese one as he asked me if I would sell him one, I did it for myself not to sell.
I don't manufacturer stuff to sell, but I can only imagine that you just can't do consumer type stuff as people will opt to buy from China cheaper, you get a small discount for buying bulk in the UK but it only works out to about £4 - £5 if you buy something like 10k parts from them, is it only specialist items that you can make money on if buying from local electronic component retailers?
I was curious to know if anyone else has had this kind of thing happen to them and what their reponses were.