|
Sagebrush posted:20 milliamps at 5000 volts (1000 watts) *100W, so more like a second metabolism and less like a space heater. Wouldn't want to dissipate all of that in a finger though.
|
#
¿
Mar 15, 2024 12:52
|
|
|
|
| # ¿ May 9, 2024 18:51 |
|
|
Stool Tool
|
|
#
¿
Mar 26, 2024 03:16
|
|
|
mobby_6kl posted:Could I just get away with using voltage dividers here? John Peatman (professor, prolific writer in the EE trade/hobby press) did this trick for talking to 5v ICs with the PC serial port (+/- 12V typically) where his level shifter was just a big (I think like 100k) resistor between the serial port and the pin. This "worked" because the protection diodes in the IC would take the hundred or so μA and clamp the voltage to near the supply and ground. Whether that really works depends on the type of IC, whether it causes you to violate any datasheet limits, whether you care if you violate those datasheet limits, etc. That's the bare minimum for level shifting down. A voltage divider is downright fancy by comparison. If you want to get into premium territory, replace the bottom resistor with a small signal schottky diode from the power supply (as in, pointing from your 3V supply to your logic level pins) and you're safe even if you have an unexpected voltage spike on the input.
|
|
#
¿
Apr 7, 2024 16:03
|
|
|
ryanrs posted:Car power is gross and nasty, so use an optoisolator. Car power can have spikes of -20 to +80V for hundreds of milliseconds. Say the spikes were 10x worse than this, like 1kV. If the resistance into your clamp/divider is 100k, your clamp (or the IC pin) has to briefly handle 10mA. The optoisolator will work of course but it seems like overkill, especially if your power supply isn't isolated. (If your power supply is isolated an optoisolator is basically required.)
|
|
#
¿
Apr 8, 2024 03:35
|
|
|
At my previous job we had a cabinet full of fancy arduino clones for all the usual bit banging/interface noise. I miss that so I designed some DIP32-sized RL78 boards. I'm not even sure 16-bit microcontrollers need to exist with so many options in ARM and AVR, but it's a thing you can buy. Now to see if I can get the thing to talk to my UART at all.
|
|
#
¿
Apr 16, 2024 17:14
|
|
|
|
| # ¿ May 9, 2024 18:51 |
|
|
Shame Boy posted:I still feel weirdly dirty every time I have something that's just a teeny bit too intense for what a lil' 8-bit fella can do and the next level up solution for basically the same fuckin' price is some dual-core ARM thing that runs at 200MHz+. This one is in the $2 range and tops out at 32MHz. You can get a 250MHz STM32 for that, but the RL78 had a better supply range and I kind of wanted to play with a new architecture. Stack Machine posted:Now to see if I can get the thing to talk to my UART at all. Welp, I only had to cut one trace so I'll mark it as a W.
|
|
#
¿
Apr 17, 2024 00:52
|
|