Comment on Is the Raspberry Pi Still an Affordable SBC? I Don't Think So
Buffalox@lemmy.world 14 hours agoI think it’s strange that they haven’t extended the 40 pin IO capabilities. For instance analogue IO would be very welcome for many purposes.
For instance analogue IO would be very welcome for many purposes.
I have a handful of the original Raspberry Pi A and B models that have analog audio built in (with 3.5mm jack) and they’re still in use today because of that built in analog audio out. Also honorable mention to the original Pi Zero which had the logic (but not the header pins) for NTSC out. I have a couple of those in use too.
Yup, it would be super convenient to have one or two pins for ADC. Technically you have a DAC on Pi 4, if you repurpose the analog audio output, but on Pi 5 all you have is digital HDMI audio.
Oh well, an AD7705 voltmeter board costs only $2, and uses only six wires for SPI connection, including one of two precious precious 3V3 pins. And you’ll also need around three days to dig Github to find a working Python driver for it. But at least you don’t have to worry about burning your 3.3V Raspberry pins with 5V input voltage.
And at this point you are asking yourself - why not pay $3 for an ESP32 or a STM32? you can program it to use just three wires - power, ground, and UART TX, and you don’t need to read it 500 times per second like AD7705 and use 25% CPU of your Raspberry Pi Zero, you can program it to calculate an average RMS voltage once per second, and you can read a total of six ADC channels on ESP32, and on STM32 half of all the pins can be configured as ADC, and it’s also quite precise and low-noise, while on ESP32 ADC is more … consumer-grade.
I made a digital drum reader using Piezos on an Arduino with my wife some years ago, For that you need way more than 2 analogue pins.
I don’t see why newer Raspberry Pies couldn’t have something like 12 analogue pins, it would be amazing for many things, and it’s dirt cheap to make today. The ESP32 has 18 AFAIK.
In some ways ESP 32 has way better features than Raspberry Pi, but it is not nearly as user-friendly and it lacks audio. It’s also not a general purpose computer with the things that entail, but “just” an embedded system, although a very good one for sure.
cmnybo@discuss.tchncs.de 14 hours ago
There’s always the BeagleBone Black if you need a lot of IO. It has a 12 bit ADC too.
pelya@lemmy.world 13 hours ago
But, but, eighty bucks! TI boards are seriously overpriced.
cmnybo@discuss.tchncs.de 13 hours ago
It’s USD $53 on DigiKey and Mouser. That’s still rather expensive for an old single board computer, but it has a lot more IO than most other computers as well as a pair of real time co-processors for handling high speed IO.