Slowly building up the library of models for the Bus Pirate Edu Kit exercises. To make sure everyone can easily hook up any exercise, we’ll add top-down views, schematics, and wiring tables. Here’s an example of a wiring table for the exercise above.
MCP9701A
- Pin1 – E1
- Pin2 – E2
- Pin3 – E3
Wires
- Black: Bus Pirate GND – A3
- Yellow: Bus Pirate ADC – A2
- Red: Bus Pirate 5V – A1
As always comments and suggestions are very welcome.
Looking forward to this, the bus pirate has peaked my interest for a long while now, with some decent tutorials and exercises it’ll make it a lot more accessible to learners like myself.
Depending on how fast you can switch on/off, and how much you can vary duty cycle… what about switch mode power supplies?
Boost, buck, invert basics just need a pulse, power supply, inductor and a voltmeter. Advanced users with access to a ‘scope can look at waveforms.
How about including a ferrite toroid in the kit? Then you can have a whole can o’ worms on transformer design, winding, B-H curves, losses related to frequency, etc. Decent toroids can be hard to find [or the postage outside the US makes them prohibitive].
HI, cool idea
Thing about switching power supplies, is that you need to have a quick feedback loop to achieve efficiency, and stability. While it is possible to easily make a BP controlled switcher it would be have to be very low frequency.
I’m making a case for an educational “concept” SMPS. If I was making a proper, efficient SMPS I wouldn’t drive it with a Bus Pirate.
But you’re right – feedback is an issue if you want a regulated output (for an example of unregulated, check out Linear’s LT3439 push-pull driver).
Sensing voltage feedback is a matter for an ADC. I thought the Bus Pirate had one. Mine is sitting on a shelf, waiting for me to stop playing with Beaglebones & Raspberry Pi’s.
Yeah the bus pirate has an ADC, but its way to slow,and the trip voltage would have to be done throuhg software, making it even slower..
Real hardware SMPS use high speed comparators for feedback, with one pin on a reference (or DAC) and the other on a feedback resistor divider..
This way you have a much faster hardware response…
Agree with Alan’s comments!
Some stuff is getting really hard to find. Or really expensive- like small analog panel meters. They used to be on every ghettoblaster, and are still really ideal for certain scenarios when a scope is not handy.
Thanks for the vote of confidence. If anyone chooses to action it, I’d suggest larger toroids are easier to wind (up to 1 inch OD = FT82 or 1605) and high permeability (-77, -J or -W material) makes for more robust designs, working at frequencies under 500KHz
Amidon’s FT-82-77 or FT-87-J, or Mag-Inc’s VJ41605TC or ZW41605TC would be my choice.