Jimb0

Tutorial - Cherry MX Switch Breakout Hookup Guide about 3 months ago

You need ground on one pin and a pull-up resistor on the other (in the most common hookup, at least.) As an example: ground pin 2 and put a pull-up resistor on pin 1. Then monitor pin 1 – if it’s low, the switch is activated, otherwise it’ll be high.

Product PRT-13777 about 3 months ago

• They Babysitter’s charge rate is ultimately limited by what your supply can deliver. So in your example, the battery would charge at a max of 500mA.
• The BQ24075’s max output current is 5A, which the board should be able to handle. It should be able to pull the ~2A from the battery and deliver it to the V_OUT pin for your GSM module.
• I haven’t fully measured the sleep mode current, but looking at the quiescent currents for both chips is a good place to start. The BQ27441 will consume anywhere between <1 to ~100µA, depending on the mode. And the BQ24075 will pull <10µA. You could also disable the power indicator LED by cutting SJ5 to save a big chunk of power.

Tutorial - Battery Babysitter Hookup Guide about 3 months ago

Yes, both chips support Li-Ion batteries. As long as they’re single cell batteries, with a voltage max around 4.2V, they should work just find with the board.

Product PRT-13777 about 4 months ago

It should be well-protected against a lower-than-specced input voltages. If the input voltage is below the battery voltage, the BQ24075 will essentially disconnect the input supply from the battery-charging and output sections. There’s also an an undervoltage lock-out feature, which shuts the chip off if the input voltage dips below ~3.3V. (More on that in section 9.3.1-2 of the BQ24075 datasheet.)

The Sunny Buddy might be up your alley, if you’re looking for a more solar cell-specific LiPo charger.

Product PRT-13777 about 4 months ago

It could work…if you isolate both chargers from each other. You’d need separate USB/VIN supplies for each charger - they couldn’t share a ground. That’d mean the fuel gauges wouldn’t share a ground either, though, so you’d need separate controllers to read from each monitor (assuming you need those for your application).

Product PRT-13777 about 4 months ago

It can definitely charge one of those 6Ah batteries. It won’t be able to reach the max charge current (6A), but the 1.5A charge rate would still work its magic a lot faster than our USB chargers.

The ICs on this board only work with single-cell LiPo’s (with voltage ranging from ~3.6-4.2V), so you won’t be able to use it to charge a pair of LiPo’s in series.

Tutorial - Force Sensitive Resistor Hookup Guide about 4 months ago

I estimated those values using the graphs in the FSR integration guide (figure’s 3 and 4) - trying to linear-ize those curves. Those equations could use a lot of fine-tuning, but they at least produce usable data.

Product DEV-13664 about 6 months ago

Yup, it’s just a few-line change here in Variants.h.

Product WRL-13794 about 7 months ago

Glad you got it all working!

The Blynk Arduino library includes a few examples which might help you get started developing your own code. Check out the ESP8266_Standalone sketch under the File > Examples > Blynk > BoardsAndShields menu. That’s a great skeleton - the bare minimum you’d need to start your own Blynk project. The hardware pins (0, 5, ADC, etc.) will work out of the box with that sketch, then you can start mixing in NeoPixels, virtual variables, and other sensors.

Product WRL-13794 about 7 months ago

The board’s WS2812 is powered at 3.3V as well - cuts it close on the blue LED forward voltage, but eliminates any undervoltage potential on the DIN line. The datasheet’s I’ve seen for the WS2812 recommend a minimum of 0.7VDD for a high, so 3.3V might be a little dicey going into a 5V-powered LED.

I had the board driving a 1m LED Strip (60 LEDs). Current was lower than I’d expect (~890mA) when all LEDs were set to max, so I suspect the regulator was dragging it down. I wouldn’t recommend that many LEDs (or more) without cutting the “WS2812 VCC” jumper and supplying the LED power externally - and, in that case, supplying the LEDs with a LiPo or something a bit less than 5V would probably be safest.