Jump to content
Sign in to follow this  
cdog4w

RCST issues and other beginner questions

Recommended Posts

Hi, I'm new to electronics and pics but not to RC. I race a 18th scale truck and in general dabble in surface rc. I've been meaning to get into the custom electronics side of RC and this site has been an inspiration and a starting point. I picked the RCST project because it is straightforward and will be useful for servo issues in the pit when radios aren't allowed to be on.

First I built a 555 based tester but that was only a warmup :) I ordered the pickit 2 starter pack along with a pic12f509 and all the parts on the bill of materials for the RCST. I flashed the pic and breadboarded the project in < 30 min and it works great with one slight issue. It seems when in manual mode, it doesn't give full travel to one side. When I flip the switch and put it in sweep mode, it will hit the full travel on both sides. I used all parts as listed, but I did use the alternate 5% C1 instead of the 2%.

Beyond this issue, I had some more general pic questions. Do these new flash parts have more features than the original C parts that would allow the design to be smaller or use fewer components? From what I've read you're reading the pot via "rc time" using resistors and caps and timing the discharge time to do the analog to digital conversion. Would using a pic12f510 (w/ 8 bit ADC) or a pic12f675 (w/ 10 bit ADC) cut down on the number of parts required?

I was wondering if it would be possible to do a data logger with a pic? I know there are many available but the intention would be learning via a useful project. I'm not sure how a pic would read current usage, but I would guess it needs an external circuit of some kind to read w/o being fried. I was wondering if a way around this would be to measure the magnetic field on the battery wire caused by current flow, though perhaps that is too inaccurate.

I also have a question about you rccam project. I was thinking of using it to trigger a CVS camcorder (hacked) to record on truck video. I'm thinking the simplest connection would be to just hook up both leads of the physical record button and then bridge them momentarily in the pic to trigger start/stop of recording. Also, this is a surface radio and I don't think the 3rd channel is proportional, so I'd probably need to tailor the project for my needs (different trigger detect, different way of causing start/stop).

To sum up, thanks in advance and thanks for having such a cool site/community!

Share this post


Link to post
Share on other sites
It seems when in manual mode, it doesn't give full travel to one side. When I flip the switch and put it in sweep mode, it will hit the full travel on both sides. I used all parts as listed, but I did use the alternate 5% C1 instead of the 2%.
If the POT or C1 are too far off in value then you will not achieve full range.

Would using a pic12f510 (w/ 8 bit ADC) or a pic12f675 (w/ 10 bit ADC) cut down on the number of parts required?
My opinion is that using the ADC would not reduce parts count. But, the existing circuit would surely have to change. And, it should be easier to write the code for the 12F675 since the A/D operation is more obvious. IMO, the most useful thing in the 'F675 is the 16-bit counter/timer, which is nice to have.

I was wondering if it would be possible to do a data logger with a pic?
There are PIC based data logger projects on the web. I don't have any links, so just try Google. BTW, to measure current you can use a current shunt type circuit and measure the voltage drop. There are battery gauging IC's too that might be useful. For example, one is used in this project: BatMon.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×