Presets used in Line Follower Robot were rotary or cermets? & What type of PCBs?

[ashour]

Hi,

I'm new to robot making so i apologize if my questions are somewhat noobish .

I'd like to know what type of presets that was used in the 40$ line follower robot tutorial available here http://www.societyofrobots.com/member_tutorials/node/59

I couldn't find any potentiometer with 2 terminal together and one alone
here is the link of the resistors page where i buy electronics :
http://ram-e-shop.com/index.php?cPath=31_76
would somebody tell me which one should i buy?

also if i couldn't find any 20k Presets can i use 10k or 50k?

Another question about the same tutorial :
I've seen the same PCB in the electronics shop but i've not yet bought it ,but i don't understand how it works , its not like those pcbs that have each 5 pins in a row connected right?

i think that each pin works by its own thats why the tutorial maker soldered anything to wires if he wanted to make connections?

Is that true?

Thanks

[waltr]

Pots (potentiometers) have three terminals and you just need to connect the center to an outer leg externally to create the two terminal variable resistor.
For your project any of the pots would work but the PCB mounted pots are smaller:
http://ram-e-shop.com/index.php?cPath=31_76_78&osCsid=f016eedab7f3c560081222edb3994bc7

As explained the the $40 tutorial the pots are wired to be variable resistors that can be adjusted from 0 to 20k Ohms. A 10k Ohm pot might work but if the adjusted value needs to be larger than 10k Ohm then it will not work.  Whereas the 50K Ohm pot will cover the 0 to 20K Ohm range so this would be a better choice.

The PCB shown in the $40 robot tutorial has a copper pad for each hole. If you need to connect several parts together, electrical connection) then you lay a wire across the copper pads and solder the wire onto these pads to have them all electrically connected.

Hope this helps and have fun
 

[ashour]

Thanks for your reply , very helpful , unfortunately the electronics shop website is running an update so the link was broken , and i'll have to go and by stuff myself no online ordering

so did u mean by pcb mounted pots the cermet ones? those ones that looked blue?

Thanks

[waltr]

Yes, the blue cermets for the web link are PCB mounted.