Dial Clock actually runs from a DS3231
This device is a kind of a joke. It is dominated by a cheap alarm clock. While the quartz crystal circuit in it is pretty good. it is nothing special.
Long ago this was used as an integrator to add solar or other currents to convert to daily ampere-hours. To do this the internal circuit was disconnected from the tiny stepper motor which drives the mechanism. All four leads were connected to external wires. The eletronic circuit pulses were used to time the integration. The motor was provided with pulses at at rate proportional to the current being measured.
For the current project the clock circuit is not used. Instead pulses for the motor are provided by a Picaxe 18M2 micro-controller. This is controlled in turn by interrupts from the one-Hz square wave output from a DS3231 clock-calendar chip. This is especialy precise, thanks to an internal temperature sensor and computer which adjusts the frequency of its internal crystal to compnsate for temperature changes. It also allows for exact trimming at the factory.
The clock continues to run continuously from its own rechargable lithium battery. Because the display is power-hungry, it is normally off. A push back on the clock activates a microswitch to turn it on tempoarally
This project was originally posted in Frbruary 2022. It was remade in June with the same circuts and program in a nicer box. The only change is a bigger battery and the Transmitter and Display boards were remade with the same circuits.
|These are the photos of the Meter.
| These are the components which constitute the Dial Clock,
|This program has been written for this instrument. It has these pages of code: