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Description:
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Welcome Jared Wolff of Circuit Dojo!
- Jared is a graduate of the Rochester Institute of Technology (which Chris also considered attending). He did co-ops while there, like we talked about on last week’s episode.
- While on co-op at Cisco, he was in the cable group and marveled at the techs doing repairs with magnet wire.
- He is an east coast guy at heart, so he moved back to Connecticut eventually
- Jared worked at Apple for a while, but the lifestyle is difficult because of time requirements and stressful travel. He was also there when Steve Jobs was still around and there was a bit of over the top hero worship.
- Nordic’s early bluetooth chipset was the nRF8001, which was a transceiver over SPI (no micro)
- Working for startups was interesting if you thrive on doing a lot of different things
- Burnt out on his last startup, decided to ride his motorcycle up and down the west coast. He got sick and ended up diagnosing himself with Valley Fever, a fungal infection prevalent in one of the places he visited.
- After healing up, he went to Taiwan for 4-6 monhs.
- There is a semiconductor fabrication program at RIT. There is a silicon ingot in a display case out front there.
- While recovering from burnout, a previous mentor hit him up for the IoT project.
- Mix of international and domestic manufacturing in his past
- A lot of military nearby in CT
- Comparison quotes with Taiwan, it was only a few dollars more for domestic production.
- Currently building a board with an nRF9160 module, the new cellular module from Nordic Semiconductor.
- Current status of nRF9160 is that it is shipping and working on different carriers throughout the world on Cat M1 networks.
- What does it take to get a modem talking to towers?
- Modems abstract commands in software
- Jared will be testing for FCC, ISED, CE
- Working with Resin
- The cellular module is pre-certified but carriers still want you to test your design on their network.
- Verizon requires over the air firmware capabilities, in case something goes wrong. The nRF91 firmware OTA is on the application side, which is unusual.
- Jared is hoping the modem will have bluetooth at somepoint as well. The external wideband antenna he is using might be good enough.
- Crowdfunding had an external antenna included.
- There are different categories of cellular service. Most cellphones operate with Cat 4 or Cat 6 connections. The higher the category, the faster the speed.
- Cat M1 is the slowest on LTE. NB-IOT is different equipment, so it isn’t even considered to be LTE.
- Based on the development from Nordic, Jared is using Zephyr to run his board.
- It’s an Real Time Operating System, but “feels” like linux for embedded. Zephyr is built on top of the chip’s SDK. “West” is the downloader that pulls in necessary dependencies, based upon a definition file.
- Huge library of boards available
- Jared wrote a post on how to create your own drivers on Zephyr
- The Device tree maintains swappability
- The nRF91 board is based on the adafruit feather form factor. Jared had previously created the air quality wing, which had various sensors:
- TVOC
- Humidity / Temp
- Particulate sensor
- Compatibility matrix on the Nordic site
- Chris recommends checking what kind of coverage you have with open signal.
- Though the first board run is no longer for sale, some boards are available soon. You can get a discount on a board at jaredwolff.com/amphour
- You can also follow along on Jared’s progress on his blog, where he also writes about firmware tests.
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