A functional update for the IV-11 DCF melody watch is available from gr-projects. It is a radio temperature transmitter. The special thing about it is, that the transmitter operating in the ISM band 433 MHz is equipped with a photovoltaic cell (solar cell). Depending on the version, a small rechargeable battery or a CR2032 button cell can be installed in the transmitter. The battery is thus supported by the solar cell in the sunlight or in the battery version it is charged during the day and then keeps the transmitter in operation over the dark time.
The assembly is easy. The kit consists of a transmitter and a receiver. The boards of transmitter and receiver are equipped with few components quickly. Here, however, some attention is required and you should read the documentation carefully, because due to the lower number of kits, the boards are manufactured without component imprint and solderstop.
The radio modules themselves are completely pre-assembled (SMD) and only need to be soldered into the corresponding circuit boards. Optionally, a trim potentiometer can be connected in parallel to the temperature sensor (NTC) for adjustment purposes. The transmitter, like the receiver, is installed in a small PVC housing. Here, except for a 3mm drill hole and possibly some silicone for the sealing of the solar cell (for operation outside the window sill) no further tools are needed.
To connect the receiver to the clock, make a few minor changes to the clock’s mainboard. First, the microcontroller is replaced – logically – because there is indeed a new program that then displays the temperature in the date line. A resistor is removed, one is added and a jumper can be swapped. The connection between the clock’s motherboard and the radio receiver is made with a piece of cable. Three lines are required (GND, + 5V and the data signal from the receiver controller to the clock controller). That’s it then already. The clock can go into operation. After a few seconds, the received temperature is displayed in the tube.
A video how to solder the circuit is available here:
I received a new kit for vacuum fluorescence display from Günter (gr-pojects). Thanks a lot!
It is a clock with Type IV-11 vacuum fluorescent display tubes for hours, minutes and seconds, and an IV-18 tube for date display, and IV-3 for displaying the day of the week. The clock consists of a mainboard with power supply, CPU, MP3 module and driver blocks for the tubes. The time is set and synchronized via an externally connected DCF-77 receiver. Later, the board will be extended with a real-time clock circuit. The power supply for the entire circuit comes from a small plug-in power supply with 12V / 1.2A. The total power consumption is about 450mA. As a special feature, the clock has a small MP3 sound module with MicroSD card slot. This receives from the microcontroller via the serial interface every quarter of an hour a corresponding command to play an MP3 file. Thus the quarter of an hour is signaled with a “gong beat”, half an hour with two and three quarters of an hour with three “gong strikes”. At the full hour, the corresponding time is announced.
The entire circuit is built into an aluminum-acrylic housing. All fittings are milled and screwed. A video of the structure and the function can be seen below:
A patience-related work is the restoration or repair of a rotary pendulum clock.
A rotary pendulum clock is, as the name implies, a mechanical clock that generates the clock from a pendulum rotating around its own axis. The vibration energy is transmitted here with a torsion spring (Horolovar spring), ie a very fine steel wire special alloy. The rotary pendulum clock is also called annual clock, as due to the very slow oscillation and corresponding mechanical implementation of the escapement, a lift of the spring accumulator only once in 300-400 days is necessary.
Of course, this also requires a certain precision of the mechanical components. If something is not set correctly here, the clock will switch off after a few minutes. Even the fine adjustment of the accuracy requires some patience. And just like a clock has done to me. In an online auction house, I have a cheap ‘defective’ but purchased from the components ago complete rotary pendulum clock and immediately started to disassemble and clean the parts.
After this work we went back to the assembly. The Horolovar feather was replaced by a new one. Now we went to the adjustments. First, I had to find out how many pendulum oscillations, more precisely half vibrations, should make the clock in one minute. At my watch (a Kundo) these are eight beats. The easiest way is to use a stopwatch to measure the time it takes to reach the 8th half-cycle. For example, if the measured time is over one minute, the watch will run too slowly and must be adjusted with the thumbscrew (the one that changes the position of the pendulum weights in diameter). Turning the thumbscrew clockwise will make the clock slower and counterclockwise faster, of course.
It should be a precision of +/- 1 minute per month possible. So a deviation of 12 minutes a year. Of course this requires optimal environmental conditions. (constant temperature and humidity, as well as a firm, vibration-free state)