Testing stepper motors with pulse generator

This is a quick portable circuit used to test stepper motors. It is based on small PIC 12f675 microcontroller. The pulse speed is changed with potentiometer. It allows smoothly variate between 20Hz and 3kHz.


It has couple jumper bridges to select enable and dir pins. Servo tester is powered with four NiMh rechargeable batteries that give total 4.8V.  This circuit can also be used as general purpose pulse generator if needed.

Nice looking PIC24 watch with OLED

Jared has been working on his OLED watch and it seems that it reached the stage when if can be to test. Watch is equipped with several great features like USB HID communication, time, date with events and accelerometer. Watch firmware is RTOS based where he wrote all necessary drivers, graphics engine and PC applications for setting things up.


He designed schematics and PCB by himself using Altium Designer software having small size in mind. Jared was about to look for 3D printer to do the case, but he found that aluminum case from iPod Nano fits just right. Watch already works, but there is much work to do on user interface and probably new features like Bluetooth, magnetometer and other things that bring it to fully featured smart watch.

PIC based Weather radio

This one is still a pending project, but you might give it a try as it’s a interesting one. In this project a weather radio is tuned using PIC and as soon as there is a weather alert, it’s broadcasted on the LCD as well as the speaker of the weather radio. As of now, PIC powers up, resets and powers up the radio, then tunes the radio via I2C to 162.55MHz. It finishes up by reading back the status and then dumps the Tuned Frequency and RSSI (Received Signal Strength Indicator) on to the LCD.


The output from the audio amplifier is a little weak and hence might require a second stage amplifier. The author also wants to add buttons for “quick tune” to the common frequencies (.40, 425, .45, etc.) and one additional monitor/standby switch. The PIC is able to tune the weather station which was brought from spark fun using I2C protocol. The hardware schematics have been provided on the website and also what work has been done till now.

PIC16F628A timer for UV exposure box

Using UV exposure technology is common way of building PCB at home. If you tried this, you probably know that exposure timing is very important to get precise image on photoresist. Overexposure or underexposure always lead to failure. So it is best to leave timing for timer. If you built your own UV box, then you should also build a timer.

Diyfan suggests simple PIC16F628A based timer project. It is really simple – 2×16 LCD displays time and status. Three push buttons allows to select time, start timer and stop timer. It also has speaker to play sound alarm when time runs out. Circuit simply send signal to a pin which can be connected to relay of your choice which then controls the lamps. Of course it can be used for other purposes including motor drive for some time, water sprinkler and other.