I’m trying to use an old Analog Accelerometer V1.0 for a personal project since I had one left over from a previous season (we have the new V5 one so there is no need to keep this one stored away). I was hoping to use it with a 3v microcontroller, but I know that the 3 wire devices are typically 5v. When I looked at the chip’s datasheet, it said that the input voltage should be about 3.3v anyways and that it could handle up to 7, but it will severely shorten its lifespan and can cause permanent damage with prolonged use.
I tried to find a schematic of the accelerometer online to see if there was some kind of voltage divider build into the chip to drop the supply voltage from 5v to 3.3v, but I’ve had no such luck. Anyone out there know if I can still use the entire sensor with a 3.3v input?
Little part named “CSUP” is, probably, a voltage regulator that converts 5V supply voltage into 3.3V suitable for the accelerometer chip.
You can always connect your accelerometer to 3.3V power supply, run test code on your microcontroller and see if it works stable enough for your needs.
In theory, you could try to solder wires directly to the board and try to bypass the voltage regulator.
However, the best thing about VEX accelerometer is that it uses old but industrial grade parts that are “guaranteed to operate over an extended temperature range of -40 °C to +85 °C” and have “High shock survivability (10000 g)”.
Also, the board is sturdy and covered with some sort of epoxy, which lets it survive a typical VRC team’s parts bin where it gets to interact not only with the random nuts and bolts but also with sharp edges of cut c-channels, axles, and various tools.
I would leave the VEX accelerometer as it is and, instead, try to get one of the newer consumer grade MEMS accelerometers that were designed to work with 3v3 microcontrollers like Arduino, ESP32, or RaspberryPI out of the box.
You can get MPU-6050 for under $3 with free shipping.
It may not be as sturdy as one from VEX, but it will give you 3 Axis Gyroscope + Accelerometer over a single I2C interface, instead of requiring multiple analog inputs.
And, if you pay a bit more, you could get a 10 DOF sensor that will also have a built-in compass and barometric altimeter.
Thank you so much! I figured they were stepping it down to be 3.3v, but I wanted to be extra sure. I will definitely look into getting an alternative chip.
