You know what is a logical analyzer. Simply speaking it allows capturing logical signal levels from multiple data lines. But what if you want opposite feature? I mean signal injecting in to data lines. Dilshan designed simple but handy device (called Kidogo) that allows injecting 8 digital signal channels with your custom pattern.
Signal generator has 512 time slots for all 8 channels where each can range between 1ms to 1s. It is driven by PIC18F2550 microcontroller. Each channel pattern can be edited in a nice PC GUI and then sent to PIC using USB interface. Simple and intuitive. This is great device for many purposes like testing various modules including LCDs, memories or simply simulating some specific hardware like digital temperature sensor.
Embedds highly recommends EasyEDA for circuit and PCB design