My objective here is to fill a niche that I often find myself needing, working in a laboratory/R&D environment. I need an inexpensive device to perform lightweight datalogging and automation type tasks. The ESP8266 is a fantastic candidate for this, with the onboard wifi and blazing fast microcontroller.
I envision a "swiss army knife" of sorts, that is good enough for the task, and cheap enough to be almost disposable.
Using an ESP8266 Multi-tool, one could connect to test points in their circuit, and record and interact with the circuit through a web-based interface.
Log voltages, digital pin and bus states, and serial communications, all from a web page with ease. Conceptually, think a hardware version of "PEEK and POKE" from the days of BASIC.
Must meet requirements
At least one analog input channel, ±12V-ish
At least one digital input for triggering, configurable via software
At least one digital output, configurable via software
Low power usage
Wide input supply range (3.3V-12V?)
Reliable time source for data acquisition (low jitter, high accuracy)
Web-based user interface for configuration of settings such as:
ADC Sample rate (continuous, triggered on input, etc.)
Digital I/O (logging/output/triggering)
At least one analog output channel
Onboard storage for datalogging
Serial port with web interface (RS232 TTL)
"Bus sniffer" for SPI/I2C
Battery power option
How do we make it as small/cheap as possible?
Pre-soldered ESP modules must be weighed against raw chips as an option
Power the multi-tool from the device under test
Small pitch connector for test probes
Is input protection critically essential?
If the device is cheap enough, can we skimp on input protection?
What are the safety ramifications?
The multi-tool is not designed with high voltage measurements in mind
Typical usage case
I need to measure and record the input and output voltage of a circuit I've built, but a typical datalogging setup isn't suitable. Maybe I'm in the back of the shop, rather than at my bench. Maybe I'm not near my datalogging computer? I can connect an ESP8266 multi-tool, and do my datalogging wherever it suits me best.
I need to measure and record a few choice signals on a piece of equipment that a customer is having intermittent issues with. I can install an ESP8266 multi-tool, configure it to record, and come back tomorrow to download and analyze my data.
I need to record a voltage, while simulating an input signal, and I want them to be synchronized. An ESP8266 multi-tool allows me to do just that, with its analog input recording and digital output pins.