As a member of the community, I want to contribute to build an ecosystem that will be viable from an economic point of view.
Fab Labs are struggling with money to remain accessible at low cost, ideally at no cost, to everybody. Fab Lab equipment are quite expensive, not only as a CAPEX but also when in operation.
It sounds fair to me to require members some kind of contribution when they use the equipment extensively. The issue is the following: Fab Lab cannot afford permanent staff that would control access, meter equipment usage, prepare bills and manage financial transactions manually.
My idea is to provide Fab Labs a device that could be installed in all locations where the Fab Lab manager wants to control access, perform automatic metering, ...
Here is the starting point: just a drawing showing how the final product would look like and how the interaction with the user would be...
I started by making a first enclosure where the AC part of the circuitery will fit (note: the pictures show one of the prototypes, not the final one. I tuned it over the time but I forgot to take pictures
I struggled with a molded part for the top cover (at the end, I will not use it)
I designed a double face PCB, with an OLED, a BLE interface and a RFID reader on the front and the MCU on the back (along with the connectors, regulator and level shifters)
This is the integration part. To start, I fix the AC/DC and the SSR on the bottom face. Then I install the two outlets (AC in and AC out). I prepare the AC wiring and I connect it to the outlets. Note there are four DC wires in the back: two for the supply and two to control the SSR
The PCB is initialy flashed with a bootloader through the ISP connector (front face, at the bottom right). Then I can upload my code over FTDI (the connector is on the back... no a great idea.. I know)
Here is the final result, with the pcb fixed on the top of the internal enclosure
The last step is to install the cover
My idea is to provide a system that could be installed in a Fab Lab, with devices in all locations where the Fab Lab manager wants to control access, perform automatic metering,... There are three parts: the Fab Buddies, the Fab Buddies Gateway and the management system.
Fab Buddies are installed within the Fab Lab where access control and/or metering is required. For example, a Fab Buddy is installed on the main entrance, to ensure that access will be granted only to registred members during some periods and to anybody during other periods. Another Fb Buddy is installed next to the big CNC, to limit access to people having the proper skills and having passed the security training. Another Fab Buddy is installed next to a 3D printer, to meter equipement usage.
Fab Buddies communicate with the gateway using BLE (Bluetooth Low Energy). The gateway is a small computer( like a Raspberry PI) that is part of the BLE network on one side and connected over a wired or a wireless link to the Fab Lab network and then to the Internet. The gateway runs a MQTT client.
The management system is cloud-based. The system handles multiple FabLabs. It offers a web portal (for members and for Fab Lab manager) and an API for future integration. Information is stored in a database.
I was a little bit disappointed when I discovered FabMan but at least it made it clear my market anylysis was not wrong. If someone made a business out of it, it means there are customers and there is a need.
Here is what FabMan bridge does and fits with my analysis
Here is what FabMan does but does not fit with my analysis
Here is what I plan to do and FabMan does not offer currently
My FabAcademy deliverable is the Fab Buddy itself and a Fab Buddies Gateway that will be deployed on a Raspberry Pi with basic configuration and a MQTT server.
My target is to keep it as simple as possible, at the lowest cost possible. It could be easier to power my device with a big CPU but it is also expensive. The minimum requirements to have a viable product are:
The Cloud based management system will be designed later, along with member entitlement and a lot of fancy GUIs.
BLE MESH: it looks really interesting (increased security, better range since the messages can hop over multiple devices to reach the gateway. It could work on my Bluetooth module (based on Nordic nRF52832 but requires an updated firmware that I cannot code in the project timeframe.
The what is clear, the who sounds obvious since I'm the only team member but the when has to be clarified. Here is the plan:
The architecture is organized around a ATMEGA328P MCU.
I'm a SW guy and I put too many details (most is out of scope) here but.. here it is !
Here is a list of component, their cost and where they come from
The main case, where all high voltage circuitery is located is a laser cut acrylic box. The cover is molded. I had multiple options for this enclosure. The best choice for a real mass production product should be to design a mold and to use plastic injection.There are numerous (and sometimes fancy) aternatives. See this site for more information.
My target is to include as many course learnings into my capstone project and I decided to go with a wood laser cut enclosure. It could have been printed as well. For the cover, I tried to use molding (vs 3d printing) to get a better finish. I changed my mind later because the OLED was not fitting well with the cover and I replaced it by a clear acrylic cover
There are two outlets and one solid-state relay. One outlet to connect the device to the 110v wall outlet and another where the controlled device is connected. A 10A solid state relay controls whether the current flows or not. There is also an AC/DC to power the low voltage part of the device.
This is a compromise between cost, footprint and usability
This module suppports BLE, with an integrated antenna
This module suppports ... with an integrated antenna
I'm not sure I can build it on my own and what are the consequences in term of reliability and compliance but I could leverage this small module as a plan B
A fab lab made carrier board support all the other components: the OLED screen, the NFC card reader and the BLE card
Here is a list of process and Fab Lab tools I will be using
The ones that end with a star are Fab Academy evaluation criteria, the others are just mine
IMPORTANT NOTE: since I was documenting as I was progressing through the course, I saved the documentation in different pages. To get a full set of up to date source files, click here .
For the electronic part, I originaly started from the Satshakit design but I finally created my own. I kept files names as they were to inherit project settings, some footprints, design rules, .. and this is why it looks like a Satshakit spin-off.