The ARDF controller was created after a request to be able to play random audiofiles for an ARDF transmitter, most existing designs were based on an 16F84, a somewhat aging design and better controllers are currently available. Also most controllers had a 5-10 mA current drain which can be improved, this design requires less than 400 uA.
To allow a very small controller footprint and flexible configuration the timer is not configured with (dip) switches but via a serial connection and a host PC. The memory option is optional and is only required for a wave file playback, all other options (CW, Single Tone, Tone Sequences and Audio Effects) do not require the I2C memory chip.
ARDF Timer / Controller: [Link]
It happens to all of us, trying to get some well earned sleep after a good day of work, and BAM! someone sticks its finger into the doorbell’s button. I know you feel terrible when that happens, after you get up and see what happened, who was looking for you, its too late and you cant get back to sleep. The author of this project, developed the solution for this problem, its a circuit that disconnects the doorbell on a timer. So for example if you feel like sleeping for next 8 hours set the timer to 8 hours and there you go, 8 hours of sleep with no-one ringing at your doorbell.
To set the timer, you just push the button momentarily, and when its released, the amber LED will come on and the doorbell circuit is disabled (the door bell button doesn’t work) for a 10 hour period. At the end of the 10 hour period, the amber LED goes off and the doorbell is enabled. 24 Hours after the button was last pushed, the amber LED comes back on and the door chime circuit is disabled again. this cycle repeats every 24 hours, and because its timing is set by a crystal oscillator, it should be able to go for months or years without needing to be reset.
The author : ” Simple as it is, I have to say that this is one of the more useful projects for the home that I’ve built. ”
Follow this Link and you will find full info and schematics on building the door chime privacy sentry.
“Door Chime Privacy Sentry” © by Richard Cappels
This is simple, and the pictures tell you enough. Denkimono.com offers you the possibility to buy a kit of this alarmclock/timer that you can assembly yourself. It is available in 2 modes as a kit or ready assembled. The kit comprises of a PCB and all the necessary components.
The assembled version comprises of a fully populated and tested CPU and display PCB. All that is required is for the two boards to be connected together and mounted on the battery. Printed instructions are provided with both forms of the product. I don’t think they supply you with schematics. That would have been nice to give others the opportunity to build the project themselves. But its their idea and their right to sell it. For full details and ordering click the Link.
This project belongs to Dim and it can be used to time anything you need, the pcb exposure time, the heating time, just anything. You can set the time between 1 and 90 minutes by pressing the up or down switches. The countdown starts by pressing the on/off switch. By pressing this switch again you can interrupt the process at any time you want. After the time elapsed the timer gives an alarm sounding the end of the process and disconnects the load.
By pressing the on/off switch you reset the timer and it’s ready for another lap. The 2X16 LCD display informs you about the remaining time during countdown and other information’s about the operation of the timer. The image shows the timer board with ATTINY2313 running with internal RC but it’s better to run it with external crystal 8MHZ due to better accuracy. The tiny is pin to pin compatible with 90S but you have to program the appropriate fuses for external crystal. You can check the project’s home page for downloading all the necessary files (eagle, HEX files etc.) and detailed instructions to build the project here.
