Hi
My son 12 yrs got the KSR6 Ladybug robot project for his birthday, and spent a few days soldering all elements (under supervision). His soldering is not perfect so we checked the position of all elements and measured ALL contacts for bad connections/ shortcuts. All seems to be in place and correct.
At our first try the robot did not react to any obstacle. When measuring voltages we found the sensor is OK, but the signal never gets past the C1 capacitor to the controlling electronics. So we shortcut-ed the capacitor with a resistor (tried 100, 1000 and 54K: no difference) and the robot reacted to obstacles!
In our static test the reaction seemed to be correct: no obstacle - both motors were activated, obstacle (mirror) M2 stops working. Nevertheless after the resistor was soldered in place (back of the PCB parallel to C1 (330), the robot reacted differently: no obstacle - M2 stops working, obstacle (mirror) both motors are activated.
As my electronics knowledge is high school level only I do not fully understand the circuit other than that it compares signals and there by triggers/ controls the voltage over M2. I can not predict output-signals, so improvising a detailed test to find the exact place were things go wrong is beyond me. The manual is not very helpful either (“check position and contacts of elements”, “replace batteries”: a little too basic for the such a kit!).
After spending a full day measuring and trying I hope this forum can help us out!
Can you please advise:
- why is the original circuit not forwarding the signal as expected, and/or why the resistor isn’t part of the original design.
- direct me to tests or probably causes to solve the above problem.
My son is completely devastated after his high expectations and I want to keep his motivation for electronics high!
Thanks
