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Quick announcement: Chris will be in Portland for XOXO fest and will be running a hangout Friday September 11th at the Lucky Lab Brew Pub from 4-6pm. Bring your projects!
Welcome, Ronald Sousa of Hash Define Electronics!
- Ron has worked for 10 years in the fuel measurement industry.
- Leeds has the benefit of being the location of the Farnell trade counter.
- Many startups in Leeds have been compared to Cocoon, a home automation / smart web cam.
- Different parts of the UK are known for different things/industries
- Bruce Kelly was the one that convinced Ron to attend the University of Leeds for his master’s degree.
- The junk box from Farnell provided lots of inspiration for projects, especially things like the large siren and PIC12s.
- Ron’s love of embedded comes from his interest in robotics.
- His background in fuel measurement and delivery comes from his first gig out of college where he had to learn how to do everything.
- Really the job was based around measuring liquids. There are multiple methods for doing so:
- Geared flow meter – liquid squeezing through gears
- Turbine – Measuring how much rotation is caused from liquids going past/through the turbine.
- Ultrasound – Measuring how ultrasonic pings change as liquid properties change.
- Mike did teardown on an ultrasonic gas meter:
- What is a meter vs a gauge?
- A meter is certified and is used in billing applications for the gas.
- A gauge does not need to be and exists mostly to alert the driver to their levels.
- The various sensors communicate on a CAN bus.
- ATEX standards exist to make sure there’s no spark.
- The calibrated sensors they were using i2c sensor interface.
- While Ron also has used a variety of PICs in the past, the NXP LPC11c14 had the right mix of peripherals for his design.
- Because density and other properties can be similar between fuels, Ron used a color sensor to delineate different fuel types.
- CAN requires unique IDs for each node. Ron also tried creating a master node and broadcast packets to sync the variety of devices on the net. As with other ID schemes, the lowest node wins because the IDs are always XOR’d to compare the addresses.
- ATEX requires traceability, including the unique IDs of each node.
- Ron seems to have, “MacGuyver syndrome”. He enjoys fixing engineering problems under pressure.
- One was an RFID solution with a relay, it turned out there was inductive kickback causing issues.
- Another they forgot a 24V to 5V optocoupler board, so Ron rigged up a regulator that did the job for 2 years.
Many thanks to Ron for jumping on the show last minute. You can see his tweets under his handle @opticalworm
Good to see someone else from Leeds! I studied electronics at the University too, although we never saw any presents from Farnell! Despite their presence, it does seem that electronics development work is increasingly being done in the South East around London, I’m finding it increasingly difficult to get work up here. On the other hand, software development seems to be flourishing.
needed optical coupler but none in the shop? almost every single switch mode power supply has one
I see them often on flyback converters (because of the higher voltage), but not bucks or boosts. Where are the optos on most of the ones you see?
feedback, every single (safe) power supply has at least one
first image when googling “liteon power supply smps pcb” :
http://320volt.com/wp-content/uploads/2010/02/atx-guc-kaynagi-pcb-uc3843-smps.jpg
optocouplers are white chips marked IC2 IC3 IC4
next picture of a pcb for this search query:
http://i00.i.aliimg.com/wsphoto/v0/1723494944_1/WORKING-GOOD–BN96-01923A-DY-450APLASMA-TV-Power-Supply-SMPS-PCB-BOARD-PART-PS42D5SX-PS42D5SM.jpg
you can see 5 black optocouplers crossing insulation cutout barrier
lets scroll a little and look for different form factor psu:
http://i01.i.aliimg.com/photo/v0/540875961/200w_dual_voltage_open_frame_PCB_mount.jpg
again one crossing insulation gap
scroll some more, oh this is a good one, “Apple iPod HIFI Dock Power Supply”:
http://www.whatsinside.info/wp-content/uploads/2014/03/Apple-iPod-HIFI-Dock-Power-Supply-High-to-Low-Voltage-Separation.jpg
diagram of a random laptop psu:
http://elektrotanya.com/PREVIEWS/power_supply/power_supply_vegyes/23432455/egyeb/liteon_pa-1121_04_out_power_schematic.pdf_1.png
optocoupler on lower right
and so on
Heck, Ronald mentioned buying a soldering iron, every temp controller soldering iron has one between comparator/mcu and triac/transistor 🙂
“single switch mode power supply”
My mind went to PCB level ones for DC/DC. You’re talking about offline switchers in AC/DC situations…many of which are flyback 😛
So yes, I agree that he could have ripped apart a lot of gear and gotten at optos…I just didn’t understand what you were referring to.