10002 Short assembly run no 2


It is quite clear that my smart home project is going quite slow and erratic. Following the other assembly, I made another batch of 5 sensor nodes. These are meant to use the new soil sensors, once they arrive. Since plants will be both outside and inside and we are talking about rain and water, the sensors will go into waterproof boxes, with the soil sensor connected via a cable. So, this assembly is due to be without connecting the sensor and installing everything in the box.

Given the nature of these sensors, I decided to skip installing the charge pump, the buttons and the USB connection.


Here are the pictures that speak for themselves. Starting with bare PCBs:

Micros soldered. Brains now added.

Capacitors added

Radio added

LEDs popped up like mushrooms after rain

Sneaky programming headers

Battery holder added, ready to hold the juice. In case you are wondering, yes, I ran out of both AA and AAA holders…hence only 5 modules today, two of which use AA batteries.

Antenna added, now these guys have a voice

Programming done. Memories implanted.

Current check OK.

Assembly time

This time, the assembly was significantly shorter: only 10 minutes per module, though I have spent a total time of around 1h 45m from start to finish (21 minutes/module), which includes getting the components and some breaks. This is significantly shorter than the previous time of 36 per module. The distribution per tasks looks like this.

Unlike the previous assembly which included the mechanical installation of the PIR sensor, the box and nad the huge delay of one module not working, this time, all 5 were ok and everything went smoothly. Plus, there is no sensor to connect or box to drill holes into. Slightly less gluing to do as well.

Is this much?

No, 10 minutes per module is nothing. Even the previous 36 per minutes is nothing. Even 1h per module is little.

Remember my initial goal? 1000 hours, 1000 euro. Well, the time budget is not going to designing PCBs or assembling sensors. No, it is going to firmware and software. I spent more time developing the firmware than building the nodes. And, I spent way more time on the controller software, the raspberry pi running node red, mosquitto, influxdb, grafana. Getting them to work together is one thing….but getting the rules, behaviour and graphs to look pretty and building nice dashboards…that takes a lot of time.


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