I am ready to place the order(s) for my parts for my first bot, however do to the overall total, which is right around $130 USD I will be doing it in two parts, off of two different paychecks.
I figured a good way to go would be to get the most expensive order out of the way, which is the one with the PICAXE starter kit, so I could start programming with some LEDs and such and such that I can pick up for cheap at Radio Shack. However I have a few questions to make sure I have everything right.
So, here's my list that I am getting from Sparkfun
PICAXE 28X1 Starter Kit
PiICAXE USB Programming Cable
H-Bridge Motor Driver 1A
The 1A motor driver says it is a comparable replacement for the L293D motor driver that fritsl uses in the Your First Robot tutorial, but is that the truth? http://www.sparkfun.com/commerce/product_info.php?products_id=315is the 1A motor driver. Also I was wondering if the http://www.sparkfun.com/commerce/product_info.php?products_id=319 dual motor gearbox they have on their is worth plopping down the money for, seeing as once I get all my parts for my first bot, I will be unable to order stuff for a month or three.
Yeah, the SN754410 is basically better than the L293D with no downsides, so there really isn’t any reason to use the L293D anymore. You can see a summary of the differences in Elliot’s comment on the L293D component page. I don’t know enough about the PICaxe to tell you if there’s anything else you need to get it running, so I’ll leave that to others.
Wrote this once before, but the posting has gone in the server change…
The SN754410 is NOT equal to the L293D. It’s equal to L293, since it does not have clamp diodes. The diodes in it are for ESD protection and they are not rated for use as clamping. We had a discussion on some other thread about this (search for L293D)
Just a thought, you could save some cash by getting the 18x setup. Either power or standard, unless you plan to use all of the ports and extra features of the 28x. You can download the files that are on the disk as well.
Also, dont forget to get the programming cable, it’s one of the forgotten items when getting the starter kits.
The sn754410 works great and needs no other parts to work.
I am going with the 28x to I am going with the 28x to start so that I can have some empty ports etc etc and then as I develop and am able to use all of them, I don’t need to upgrade (extremely tight budget makes this a little more sound long term solution for me), and I have the cable on the list, but I think that 26 USD is a little steep, oh well.
This is correct, if you get the sn754410 youll need to add 2 external 1 amp diodes on each motor output.</p><p>Its probably just easier to get the L293D instead.
I have some vested interest in this due to the fact that I have one of the 754410’s and running tests with it currently. Anyway, I’m a bit confused about some of the info on this driver and the information being given in this topic and the one I have linked. So…after reading the l293d article on this forum https://www.robotshop.com/letsmakerobots/node/2074 , and going back to the datasheets , then doing some searches, I noted that the datasheet specifies input clamping as well as high and low output clamping(pge 4 on the datasheet I have)
l2936
VOKH High-level output clamp voltage L293D: IOK = –0.6 A VCC2 + 1.3 V VOKL Low-level output clamp voltage L293D: IOK = 0.6 A 1.3 V
754410
VOKH High-level output clamp voltage OK = −0.5 A VCC2+1.4 VCC2+2 VOKH High-level output clamp voltage IOK = 1 A VCC2+1.9 VCC2+2.5 V VOKL Low-level output clamp voltage IOK = 0.5 A −1.1 −2 V VOKL Low-level output clamp voltageIOK = −1 A −1.3 −2.5 V
I also found several articles that state the same fact that they do have clamping diodes as well.I can’t verify that the people know what they are talking about, but they were mainly in robotics forums like ours…
Can someone provide some insight into the info that I’ve provided…is the issue of the 754410 that the lowlevel clamp voltage is a negative value? I’m not very familliar with clamping diodes and the such so this might be my own nievity of the subject. Anyway, just thought I’d throw this out there in case this comes up again…which it most likely will
The SN754410 internal chip diagram shows output diodes but apparently these are only for protection from static, not back induction from the motor. Also the hookup diagrams in the datasheet show extra diodes too.
