I have a project with a Wemos D1 mini and a 4-channel relay module with optocouplers. I happened to have quite a few 5 volt Pro Minis in my parts bin so I decided to go with level shifting. The DWM1000 runs at 3.3 volts, so this avoids the need for level shifting to connect to the 5 volt logic on 16 MHz Arduino Pro Mini. I'm not responsible if you break your board, because you're using counterfeit Plato side cutters or something like that. The author of the open source project based his design on an Arduino Pro Mini running at 8MHz and 3.3 volts. To get DAC2 to function normally on a Wemos S2 Mini (and its clones), very carefully use a pair of decent quality side cutters to remove/destroy the resistor circled in the image above, between the USB-C port and the ESP32-S2 chip. An arduino pro mini could handle up to 4 ACS712 with analog inputs (4 6 - SCL & SDA). (There was no way I was going to do that with a soldering iron.) Surgery complete.Īnd now.? Now I have two 8-bit DACs that work identically, and everything else is just as it was. The problem of random initial state could be solved with pull-up resistors at the output of the PCF8574. It's that teeny tiny resistor that we need to deal with.Īnd so I removed it with my Micro Nippers, as carefully as possible so as to not hit the capacitor just beside, or leave any debris behind. Using a multimeter in conjunction with the schematic and the nice hi-res photos of both sides of the board on the Wemos site, I tracked down R4. Given they were around £2.40 each, I figured it was worth tracking down the resistor and disabling it in some way, and writing off the cost if it went wrong. (PN2222) I am powering the project with a 10000mah 3. So, with that in mind, it looks as if you can safely remove that resistor and the chip will keep working. Hello I need to power a sensor that takes 12-24v Supply 11-28 VDC Load Resistance (mA) <(Supply-11V)/0.022A Load Resistance (VDC) >4k ohm I bought this boost converter and these transistors.You generally want a large resistor value (10k), but you don’t want it too large as to conflict with condition 2. Your total pullup will be: 4k7 // 10k // 7 times 50k 2k2. The Arduino Mega has 10k pullup resistors on the board, and every Arduino has internal pullup resistors enabled for I2C. The lower the resistance, the more power will be used when the button is hit. The Arduino Mega has the I2C at other pins. For condition 1, you dont want the resistors value too low. Researching a little further, I found that Sparkfun's board with this chipset on has a solder jumper/bridge on the back which allows you to disconnect the resistor on this pin, which allows you to get proper DAC capabilities. The value of the pull-up resistor controls the voltage on the input pin. (Yes, this page is that document.) R4 is the problem. This annoyed me enough to not only try and do something about it, but also document what I did. An external pull-up resistor to Vcc on the pin the DAC is tied to means that, instead of a range of (roughly) 0-3.3V, you get a range of 1.65-3.3V on this one. However, Wemos followed the chip manufacturer's designs and a questionable choice made one of the DACs more or less useless. The S2 Mini has two built-in 8-bit DACs in its arsenal, and it was that fact that made me turn my back on the Arduino Pro Mini I'd started a project with. Both are crazy cheap - the Pi Pico is £4.30 locally, and I got five S2 Minis delivered from China for just under £12 - super capable and CircuitPython compatible. What's the point of persevering with, say, an Arduino Pro Mini, with its lack of power and useful peripherals (not to mention no USB port) when, for the same price, I could be using a more efficient 32-bit offering with both bells and whistles?įor reasons I started going into, then got bored writing (and figured out any potential reader would get more bored than me), my development boards of choice are now the Raspberry Pi Pico and the S2 Mini (ostensibly by Wemos, but it looks like there's many more clones about than originals). I've decided that 8-bit microcontrollers need to be dead to me. A delightfully specific post title, and we'll get to it in a moment after some preamblic verbiage.
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