A journey on making a custom SBC

A project log for FCThermostat: Another overengeneered IOT device

A new way of thinking to a IOT thermostat:

NicolòNicolò 11/08/2018 at 20:050 Comments

Hi, as you may have noticed from the title of this thread I'm working on creating my own SBC. You will wonder why this crazy idea, when the market is full of these products. Unfortunately all the products already present in the market are "huge" compared to the dimensions that I need to respect. (Some are just a couple of mm off )...
Initiallyct my project was meant to use the SOM "C.H.I.P. Pro" but, as many will know, they went bankrupt.

I do not need a lot of processing power, the only fiew requirements are:

I started looking at other SBCs in the market, many had only the SD, or a NOR SPI.

Initially I wanted to use a MIPS chip (like a mediatek MT7688 or MT7628) for convenience and available choices... but mother Google did not allow me because of its proprietary library.

I kept looking. By now disappointed by the solutions I started to print some SoC product briefs. I am an open source lover and for this reason I opted for Allwinner. (Despite the poor collaboration of the company the sunxi community has done a really good job on porting the drivers to mainline linux and datasheets are avilable for free).
I started reading the datasheet for my selected chip the R16 or the A33 and with a little patience I started to realize the wiring diagram. (I used a already made board to understand some stuff the datasheet provided/found on the net sucks at describing what some pins does/works).
Time passed and I was still deciding which interfaces to use, how much RAM and so on. Then I discovered the Neutis N5 module, they were doing what I had started. I remember that I was happy, just a few weeks left to release the board. Suddenly the date was moved, it kept changing month after month. Fed up I decided to resume the project of my SBC.

Being a hobbyist I have always used Circuit Maker to make my PCBs, I have never had to use more complex software. (Before I used Eagle but Autodesk licensing ruined it). The project continued, and using a reference board similar to the one I wanted to realize I started to position the components, to create the nets and everything else. It's been less than two years since I started. From the initial project I had to make several changes: the most important was that manufacturers have discontinued the 8Gb RAM DDR3 chip, now there is a scarcity of 100nF capacitors and who knows what else will come out.

The Neutis N5 module is almost close to release (if they don't keep changing the shipping date) and so I no longer need to continue making this SBC. Al the work I did was done by a hobbyist, I'm not an electronic engineer, no one taught me how to make these boards. I used the informations available on the internet to document me. My SBC will not see the light of sun, because the production cost of that PCB is close to 2k with assembly and parts).

Today I'm stuck because of this Front board that is still a concept, and the fact that the Neutis module continues to delaydoes not bode me well.

Do you have any alternatives in mind?