| 08:45 | topi` | delete: have you tried the failing microSD on another device? |
| 08:46 | topi` | hummingboards don't die, they just fade to obsolescence ;) |
| 08:46 | topi` | I have several; no recorded deaths so far |
| 15:16 | delete | topi`: yeah, I used the same card in a rpi and it worked just fine |
| 15:37 | topi` | ok, then, something's gone amiss |
| 15:37 | topi` | does HB GPIOs use the same +3.3V signaling as Raspberry PI 2/3? Meaning: can I use stuff developed for the RPi? |
| 15:38 | Defiant | hb is 3.3 |
| 15:41 | topi` | I need to calculate a suitable resistor for bringing a signal in from a +12V switch (this is an alarm system) |
| 15:42 | topi` | so if I just connect a resistor between the GPIO pin and that +12V signal pin, I might get a voltage around 3.0 volts +- 0.5 volts and hopefully the i.MX6 will detect it correctly |
| 15:42 | topi` | my electronics skills are on a very basic level... |
| 15:44 | Defiant | in that case: how about using a relais? |
| 15:44 | topi` | it gets expensive soon :) |
| 15:44 | topi` | I hope to bring up to 15 different alarm outputs into one single HB |
| 15:44 | topi` | as cheaply as possible |
| 15:44 | Defiant | but you know that a single resistor is not enough? |
| 15:45 | topi` | probably not. I need to check the exact setup |
| 15:47 | Defiant | its called voltage devider |
| 15:47 | Defiant | divider |
| 15:53 | topi` | thanks :) |
| 15:53 | topi` | google found some articles |
| 16:14 | topi` | duh. I should use an optocoupler, says stackexchange |
| 16:14 | topi` | I wonder if there are any readymade passive devices which provide optocoupled 3.3V signaling |
| 16:17 | vpeter | topi`: 3.3/5V optocoupler |
| 16:17 | topi` | vpeter: the source signal is an alarm bell, operated with +12v |
| 16:18 | topi` | I can find Relay modules w/ optocouplers, but I wonder if it's the same thing |
| 16:19 | topi` | since Relays usually are used to *control* the 12V appliances, not read their state |
| 16:21 | vpeter | Ah, you mean 12V signal to 3.3v input to HB? |
| 16:54 | topi` | yeah, there is a 12V signal out there, and when that 12V changes from open to closed, then we need to detect it on the HB |
| 16:54 | topi` | damn, there are some ready products for RPi, with 16 channels, but they're limited to 5VDC on the input side |
| 16:55 | vpeter | Use a resistor. |
| 16:55 | vpeter | on every input line. |
| 16:55 | vpeter | Can you post link to this? |
| 18:35 | topi` | no links available, the plan is inside my head |
| 18:35 | topi` | there seems to be a Level shifter at sparkfun which is cheap and has 4 inputs, tolerates 0..+20V |
| 18:36 | topi` | https://www.sparkfun.com/products/12009 |
| 18:36 | topi` | here. I looked at the specs and it seems to work when converting +12V input to 3.3V |
| 18:36 | topi` | however, I'm not sure if it matters if the other side has a proper pulldown or not... |
| 18:40 | vpeter | I would use something like that: https://www.sparkfun.com/products/9118 |
| 18:42 | vpeter | on 12V you have one resistor and the other side just one pull-up. Probably no need for extra transistor. |
| 18:43 | vpeter | http://raspberrypihobbyist.blogspot.si/2012/09/gpio-input-circuit_19.html |