Picaxe Upgrade for $5 Line Follower

[erco]

I fabbed this Picaxe "shield" to upgrade a $5 Chinese line follower to programmable robot. It replaces the stock LM393 dual comparator. Pretty basic (no H-bridge so motor forward on/off only) but it's nice to have an upgrade path for students who have built one already. More to come.

 

[Jeff Haas]

Erco, did you ever release the schematic for this?

 

[erco]

No, it was a quickie slam to prove a point but I can prolly sketch something up if you are interested. My intention was to get a few sensors on it, maybe even a mini breadboard area. Just trying to get some extra mileage out of these cheap line followers.

That could justify adding a 5V booster for some sensors, so it could get complicated...

 

[Jeff Haas]

If you have the time, just put enough together so I know how to connect a micro instead of the chip. I have one of these that would be good to repurpose for quick tests.

 

[Jeff Haas]

I took another look at your breakout board and compared it to the LM393 datasheet...here's what I got:

1 - Out to motor 1, in from 08M2 pin C.1
2
3
4 - GND, from socket to 08M2 pin 8


8 - VCC, from socket to 08M2 pin 1
7 - Out to motor 2, in from 08M2 C.2
6
5

Plus the parts for the download circuit. Is that it?

Then the code would drive the pin for each motor high to turn it on.

 

[erco]

Yep, that's it exactly, not much to it. I put a 14 pin socket on so it could also take a 14M2. I plan to add an IR receiver and a few extra connections for bump sensors, light sensors etc.

 

[Jeff Haas]

Note...you need to drive a pin LOW, not HIGH, to turn on one of the motors!

Had me confused for a bit.

 

[kranenborg]

... I plan to add an IR receiver and a few extra connections for bump sensors, light sensors etc.

I would then suggest to use the IR receiver using interrupt-based control (since the IR protocol can trigger the interrupt, then one can simply read the code). Thus even a simple 5$ device can perform autonomously whilst also allowing IR-based control. For a code example, see this link

/Jurjen