
Speedometer with Atmega328p, OLED, BMP280 and 433Mhz receiver
STDSpeedometer with Atmega328p, OLED, BMP280 and 433Mhz receiver
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:Description
More compact speedometer with OLED display and temperature measurement.
This is the version 2 of the ATtiny85 speedometer. It features an ATmega328p uC that has more memory, pin functionalities, higher frequency and to which you can easily find the needed libraries (the ATmega328p is used on Arduino Uno). A serial-to-USB converter is needed for programming. It has the previous version's battery charging and protection circuitry, with the exception of the temperature sensor (v2 has BMP280 instead of TC74). I will be using it to measure the speed of my bicycle and determine the temperature around me on my rides.
The project consists of 2 pcbs: the sensor that will be mounted on the wheel of my bike and the actual speedometer.
The wheel sensor sends radio pulses via the H34A transmitter module each time a magnet passes through the Reed sensor. Each pulse will be then received by the H3V4F 433MHz receiver integrated in the speedometer board.
The ATmega328p uC calculates the speed of the wheel and constantly reads the temperature and altitude using the BMP280 sensor by which then prints the values on the oled screen. The uC can also read the battery voltage.
The speedometer circuitry will be supplied with a LiPo battery. The charging and protection circuits are based on a LiPo USB charger board commonly found on Aliexpress.
Work in progress...
Design Drawing
BOM
ID | Name | Designator | Footprint | Quantity |
---|---|---|---|---|
1 | 1N4148WS T4 | D1 | SOD-323 | 1 |
2 | 4.7K | R1 | 0805 | 1 |
3 | XC6206P332MR | XC6206P332MR,XC6206P1MR | SOT-23(SOT-23-3) | 2 |
4 | 4.7uF | C2 | 0805 | 1 |
5 | H3V4F-433M | U4 | H3V4F-433M | 1 |

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