This is a Kees/John controller built with a spare chip. It is followed by a switchable divider. It shows the versatility of the controller, the display can be configured to show the actual output of the divide by 128. It does not need this divider, but it does allow low frequencies to be generated for LF Softrocks and other things! The LCD obtained from Cecil is shortened by cutting about 11mm (~3/8 inch) from each end. This removes the contact pads but wires are easily soldered to points on the board.
Further versatility is demonstrated here, I used a mouse rotary encoder, the controller allows the tuning rate to be set to accommodate 12 or more pulses per increment.
I assembled this on a small piece of PCB using SM components but any method can be used. D1 and D2 are contained in one package at the mouse encoder. The cogged wheel is between that and the LED. You may well find they are connected like this with the +5V common. I do not think the resistor values will be critical, any in the same range may well work. I just used those because that's what I had in SM! The transistors again can be any small NPN device. The + voltage with the controller is 3V3. With other applications it could be higher, and mine still worked at 2V. The Pulse connections go to U1 pins 15 and 16. A separate push-button is used at pin 14. The "Internal Pullup" resistors, of course, are contained in the chip's circuitry. You will have to devise a way of removing the encoder assembly from the mouse, a certain amount of cutting and gluing will be required! As the controller allows the number of pulses per increment to be set I left the cogged encoder wheel complete, this could be modified to suit other needs.
Si570 controller http://www.qsl.net/k5bcq/Kits/Kits.html
G4ZFQ Index page.