Car won't work

tommyboy26

I got a sound reversing car kit assembled it all but it won't work and I'm totally lost as to why.

I have attached some photos in case someone spots something

zg3409

If you are in Dublin bring it to Electronics night every second Monday, soo TOG.ie for the calendar.

Normally the microphone is supposed to hit the object, so it should be tilted over and stick out, and when it hits and object it reverses the motor. Then a mechanical system causes it to go a 1/4 turn, and then it starts forward again. Can you link to the kit and tell us if anything at all happens when you apply power? Have you a voltmeter/multimeter and do you know how to use it? Are you sure the right resistor value is in the right place everywhere? Are you sure there are no shorts between connections that are not supposed to connect?

tommyboy26

I have just gone over everything and all the resistors are in the correct place ad are the transistors and capacitors.

There is a total of 3 capacitors on the board they are a 223 ceramic capacitor, a 47uf electrolytic capacitor and a 1uf electrolytic capacitor.

Now the 223 capacitor did not have a polarity on it but the other 2 did. Should it have had polarity?

Here is a link to the model

http://irishelectronics.ie/epages/950018241.mobile/en_IE/?ObjectPath=/Shops/950018241/Products/2192&Locale=en_IE

zg3409

tommyboy26 wrote: »

Now the 223 capacitor did not have a polarity on it but the other 2 did. Should it have had polarity?

Here is a link to the model

http://irishelectronics.ie/epages/950018241.mobile/en_IE/?ObjectPath=/Shops/950018241/Products/2192&Locale=en_IE

No. Often smaller capacitors are not polarity dependant.
You still have not said if anything happens when you put the batteries in, nor if you have a multimeter?

Have you the correct transistor in the correct place (they might all be the same)

If you can also include a clear version of the instructions as a photo that might help. Can you call into the TOg hackerspace in Dublin (Where are you based?)

zg3409

It is hard to be certain as the image is a little blurry, but I think there may be short circuits in the areas marked in red. Check that the points marked are not joined. There should be air between each one. Try remaking the connections. If there was shorts, it may have damaged some of the parts, but it may be OK, once the shorts are removed.

tommyboy26

zg3409 wrote: »

No. Often smaller capacitors are not polarity dependant.
You still have not said if anything happens when you put the batteries in, nor if you have a multimeter?

Have you the correct transistor in the correct place (they might all be the same)

If you can also include a clear version of the instructions as a photo that might help. Can you call into the TOg hackerspace in Dublin (Where are you based?)

nothing happens when i put batteries in and no i do not have a multimeter:o

yes i rechecked all the transistors and they are in there correct places.


the instructions are not great tbh and im in kildare hackerspace is in the city center?

tommyboy26

zg3409 wrote: »

It is hard to be certain as the image is a little blurry, but I think there may be short circuits in the areas marked in red. Check that the points marked are not joined. There should be air between each one. Try remaking the connections. If there was shorts, it may have damaged some of the parts, but it may be OK, once the shorts are removed.

this might be the issue. for every solder point it should only have solder on the connecting piece ie capacitors,transistor etc?

there should not be solder joining the 2 legs? only a bit on each leg?

zg3409

Yes, every dark green part, covers a copper track. Each track should only connect to the right parts and not the wrong ones. It does look like this might be the issue.

tommyboy26

zg3409 wrote: »

Yes, every dark green part, covers a copper track. Each track should only connect to the right parts and not the wrong ones. It does look like this might be the issue.

i fixed the soldering as best as i could but its still not working. i probably blew something when i tried to power it on the first time

zg3409

If you bring it to electronics night in TOG they might be able to get it running again. If you cannot attend, then buying and building a new kit or a simpler kit to start with might be the way to go.