WTB: AP4 Autopilot

[akcarl]

I am looking for an AP4 autopilot... does anyone have one that they would like to sell? Thanks!

[rjet]

There is a guy on ebay with the userid ep92 who sells one every month or so. Here is a link to the last AP4 he sold. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=6015454541 Try emailing him and see if he has any in stock or check ebay every couple of weeks.

[akcarl]

thanks rjet I just emailed him!

[mckaneorg]

who makes the ap4? is there someone who has a link?

[akcarl]

mckaneorg, this is the only link I have ever found for the AP4: http://plaza.ufl.edu/nuclear/ap4instr.html

from what I can tell off of these forums is that the AP4 was made by someone named John who was a student or worked at the university in Florida that the above website is associated with.

[mckaneorg]

interesting.... seems like a decent product. I think I may explore the RCAP project a bit more. Has anyone tried it before? Good / Bad?

[libelulamodelos]

where can i buy one of this?

[akcarl]

libelulamodelos... that is kind of the whole point of this thread. If I find a source that has more than one unit available I will pass the info along to you.

[CRT_PJ]

The ebay auction is the only way to get one from this guy. He would not sell any other way. I have one but have not tried it yet.

[moon-dawg]

I purchased an AP-4 from EP92 about a year ago off of eBay. At that time he sent me an Email and claimed that the unit was made in China. He gets a few from time to time from a Chinese exporter and sells them.

The AP-4 unit has rudder, elevator and aileron control. The RCAP only has rudder control. The AP-4 uses the same PIC chip as RCAP, it may just be 3 of the circuits used in RCAP. I have not looked that closely at it since I have been busy working another project. Hope to get back to it soon....

[Mr.RC-CAM]

I see that the last auction went for $226. Is that a typical price for it?

[icebear]

Does anyone know if the AP-4 has any stabilisation built in? Or is it intended for use with an external wing-leveller? I read the instructions but couldn't figure that out.
Also, it isn't very clear if you can program the altitude. I suppose the AP4 takes the altitude reading from the GPS.
Would be interesting to know more about peoples' experiences with this unit.
I emailed 'john' about purchasing one and he referred me to the Ebay auctions as indicated above.
/Icebear

[CRT_PJ]

AP-4 is a navigation device. It does not have any flight statbilization. You provide it aerodynamically or electronically. GPS altitude is used for a type of altitude hold, but I wonder if you can actually program it. It seems that some GPS units allow you to set waypoint elevations. I'll be using mine with a flight stabilizer.

[moon-dawg]

I have been following the winning bids over the last year and $226 is a high. It has sold for as low as $125. The auctions are no reserve. It just depends on how many people get interested in the auction.

[JettPilot]

I had an AP4, it is not programmable. It used route data from the GPS. The altitude hold is set when the unit is activiated. In other words, if I activate the AP4 remotely at 500 feet, that is where it stays....

I do not think that the AP4 is made in China, it looks like it was made in someones dining room table, definately not a productoin item. It is made cheap... I replaced all the very cheap, short sevo pigtails on my AP4 with high quality JR pigtails since my elevator was going through it. I also replaced the jumpers as the ones on the unit fall apart as soon as you unplug them. I think the student that is selling them is trying to keep the prices High by selling one every month or so. It is dissapointing that he will not support them in any way. The AP4 works fine, but for the price this kid is getting, he should support them a bit or at least answer emails. It is pretty lame that this kid is hiding behind Ebay, and ignoring all communication. He used to lie and tell everyone that the AP4 was made in China, now he just ignores everyone and does not answer emails.

It took me a while to figure out that the AP4 does not like servo leads run through carbon fiber tubes... Many test flights until I figured out why it worked perfectly when tested but not in the plane. A servo opto-isolator solved the problem. It would have been nice if this kid would have just answerd my emails to tell me what the problem was.

Many of the AP4's sold for 350 dollars and a bit more over the summer. Prices have gone down a bit as this kid has started to make one every couple weeks instead of the one ever couple months he did over the summer. At these prices, if they were comming from china he would be selling a lot more than just one every month or so. Its obvious he is making them on the side. If it was just a matter of buying and reselling, he would be selling a lot more....

The AP4 works, but dont expect any support. The instructions are what you get on the web and thats it. I would like to see someone produce a unit like the AP4 that would be honest and support them a bit.

Attached are pictuers of my AP4, before and after I replaced the servo leads.

JettPilot

[CRT_PJ]

He answered my emails. I paid just over $100. Yes, you have to understand what you're doing to get one to function.

I think he's staying below the radar for a reason. Supporting a product like this would be a huge effort if they sold by the hundreds for $100 a pop.

If it was made in China you could get them from other sources.

Anyone spending $300 on this item doesn't know what they are buying. Too bad for them. Reading his manual I knew basically what the device did. It was worth $100 to me. If it does what it says I'll be happy, that's what I bought it for. If I need something better, I'll be looking for other solutions.

[rjet]

I'll second that. He was very helpful in setting up my autopilot. I met with him and he installed it and test flew it in my plane for just the $150 I paid for it. One of the problems with autopilots in this price range is that there is not much profit for them to provide much support. What is this guy profiting? $50 a month? If you take a look at Unav they had a similar product and just yanked it off the market so they could sell other autopilots for a higher price.

[JettPilot]

How long ago did you guys buy your AP4's ?? It must have been quite some time...

The AP4 has been selling for 300 dollars + on ebay for at least the last 6 months, and thats they only place they are sold. A couple have gone for less, but not much less.... As far as support, again myabe a long time ago he answered emails, but he does not anymore. I tried to contact him many times, and so did a friend of mine, with never an answer.


The last AP4 on ebay sold for 225 dollars, much cheaper than they have been all summer. The kid got a complaint and negative feedback on one of his AP4 transactions...

DISHONEST SELLER! Refused my payment and sold the same article at a higher price

Buyer hawahabu ( 56) Aug-17-05 13:41 5981549465
Reply by ep92: dishonest? His address is Venezuela. Auction says US bidders only. Refunded 6/20 Aug-20-05 12:08

Follow-up by hawahabu: Payment was made from my US account and my physical US shipping address provided Aug-26-05 05:40

........

[rjet]

I bought one directly from him over the summer and emailed him a few weeks ago and he answered me. Can you show me where he sells them for the outrageous price of $355+, or are you just soliciting business for a competitor? Most of the ones I have seen this year were around $175. He hasn't sold any on ebay for the last 4 months, so maybe he is tired of selling them.

[libelulamodelos]

where can i buy this thing?

[Vindication]

Vent taken.

Although it is the kids perogative to do it this way. Maybe it would be a smart move for him to mass produce though!

[typicalaimster]

Didn't someone say that he is importing these from China? If that was the case then they are already being mass produced.

[moon-dawg]

rjet,

What you say is true...I have a watch on EP92 auctions and get an email every time the auction is about to close. I have not seen an auction in 4 months and I have never seen a $355 winning bid.

I sent many emails asking tech questions and EP92 got back to me in less than 24 hours. The item was shipped and received within 3 days of when I paid him.

I was concerned about support. He told me they were made in China and no support was available. I went ahead and bought one anyway since there is nothing else in the under $200 price range that will hold altitude.

[typicalaimster]

I just emailed dood and he said he's out for 2 weeks but he will let me know when they are available. How about a few of us start another "How To" thread on setting these things up? That may help his support a little.

[Mr.RC-CAM]

Not that it matters in the grand scheme of things, but I doubt it is assembled in any sort of quantity by a Hong Kong mfg. The axial caps look like Kemets and the DB9 connector shown in his Nov auction appears to have the Amphenol name printed on it. A Hong Kong mfg would never use these parts since they have vast local resources from much cheaper sources.

However, if it is made in the Far East, it is probably just a little fellow that does them as a part time hobby-business. It is just $20 worth of parts, but a properly designed and tested product is worth MUCH more than that. I think a fair price would be $125-$150 if it came with some basic support.

[Medve]

One great feature it does have that many others don't is the "mission servo", that can be programmed to activate at 20 different GPS waypoints. The last time I emailed him, he said he was working on a newer version that would have at least one more mission servo.
This could allow you to photo over desired areas outside your radio range, and then come back and maybe cut the motor power and glide to a landing while still under GPS controll.

[JettPilot]

are you just soliciting business for a competitor?

I have no interest in selling anyone elses autopilots. If was promoting another autopilot, I would do it on its merits, NOT by talking about the AP4.

He hasn't sold any on ebay for the last 4 months, so maybe he is tired of selling them.

EP92 sold an AP4 for 225.00 dollars on November 27th. Item number: 6015454541 Much less than 4 months ago. And well over the 175 you say they have gone for...

Can you show me where he sells them for the outrageous price of $355+

I had an AP4 but wanted an autopilot with barametric altitude hold, so I sold my AP4 on ebay over the summer for 350 dollars, which was the going rate for the AP4 at the time. Every AP4 that sold in that time frame went for about 350 and mine was no exception. You totally missed an AP4 that sold just two weeks ago, you obivously have not been watching them like you claim.


rjet, you are wrong on most EVERYTHING you said in this post. ? Weather your false statements were intentional or not, it maks little difference, you should get your facts straight before posting. Misleading and bad information does not help anyone.

[JettPilot]

I just emailed dood and he said he's out for 2 weeks but he will let me know when they are available. How about a few of us start another "How To" thread on setting these things up? That may help his support a little.

Its always an excuse with EP92, bottom line is, you never get a straight answer from him. The AP4 is not mass produced, and I dont think it comes from China like he says, just look at this circuit board, it looks like it is something that is put together on someones dining room table... MrRC Cam is correct, the parts do not look like they came from China... If you know anything about electronics, its painfully obvious...

I have zero interest in helping support a guy that lies about where his products come from, and plays games with his customers, and refuses to support his own products.... I beleive in exposing bad business practices, not helping them.

[Vindication]

Someone should make some code to do what the AP4 does on the gumstix platform. You can get a 200mhz gumstix with a serial port and servo drivers for less than 200!

[Blue Sky]

I don't see any voltage translation for the serial port.
Is it not RS-232 compliant?
Are standard GPS interfaces RS-232 compliant in respect to voltage?
Can the AP4 be programmed from a PC?
Am I missing something?

-Dave

[rjet]

Dave,
GPS interfaces are not standard RS-232 voltages they are only +/- a few volts. The microcontroller in the AP4 could be reprogrammed, but it would be a lot of work. Anyhow, EP92 has the best autopilots under $800 and provides the best support. I asked every other autopilot mfg. for technical support and test flights, but I could not find anyone else to help me there. He was happy to meet me at the airfield and answer all my questions. That makes a big difference.

[Mr.RC-CAM]

I don't see any voltage translation for the serial port. Is it not RS-232 compliant?The PIC can easily accommodate the RS-232's +/-12V signals with very simple circuitry, especially since it is a receive only data application. If using the hardware serial port on the PIC then it is most often a single transistor and two resistors (evidence of that is seen in the photos). If a bit-bang software based serial port is used instead, the interface is a single resistor.

[Blue Sky]

Thanks guys!
I didn't realize it could be done so simply.
That's good to know.
I'm mainly interested in a fail-safe for AP work.
I'd like to get more down and dirty than just a
plug and play setup.
I may go with a Basic Stamp and Garmin Gecko
for guidance and a Copilot for stability just to get started.
I think the Golden Age of computerized RC flight will
soon be upon us. Can you imagine planes for beginners
that simply won't crash and that will always stay within
the bounds of the flying field?
By the time I have my GPS guidance and autopilot set up
GWS will probably have something better for a hundred bucks!
-Dave

[JettPilot]

The microcontroller in the AP4 could be reprogrammed, but it would be a lot of work. Anyhow, EP92 has the best autopilots under $800 and provides the best support.

The microcontroller in the AP4 uses a security bit and can NOT be reprogrammed. An attempt to reprogram it will most likely erase the memory and render it useless.

I got NO support dispite many attempts to contact EP92 reguarding my AP4. The seller EP92 has been telling everyone that these things are made in China so that he does NOT have to support them. EP92 that sells the AP4 has NO contact phone number, does not provide any contact information or written instructions for the AP4. The only thing you get are the instructions that are listed on the ebay ad. rjets claim of great support is totally wrong.


EP92 has the best autopilots under $800 and provides the best support.

The Pico Pilot is far superrior to the AP4 , and is under $800.00
http://www.u-nav.com/

rjet has been posted false information and been wrong about everything he has said about the AP4. Go back to page 2 of this thread, and check what rjet says, read my post, and check the facts on the web for yourself. You would not be wise to take advice from someone that posts so much bad information.

JettPilot

[rjet]

JettPilot,
We know that you are trying to develop a new autopilot to compete with the AP4, but please do not call people liars just to further your business.

Here is the thread of Jettpilot's autopilot project that he is trying to sell: http://www.rcgroups.com/forums/showthread.php?t=420499

Conflict of interest?

[starcad]

JettPilot, 2nd rule of business is "Never knock anothers product when your trying to sell your own"

Your hurting yourself

[JettPilot]

JettPilot,
We know that you are trying to develop a new autopilot to compete with the AP4, but please do not call people liars just to further your business.

Here is the thread of Jettpilot's autopilot project that he is trying to sell: http://www.rcgroups.com/forums/showthread.php?t=420499

Conflict of interest?

I am NOT trying to sell anything. Your last post is not only wrong, it is a blatent LIE. Read the thread, given the limited choice we have, I am trying to get people to develop an OPEN SOURCE autopilot, that anyone can buy from Gumstix, NOT ME.

Here is a what I typed on Sept 27th in the thread in question.

"I would definately like to see this an open source project My thinking is, if I can get one of these flying with basic autopilot functions others in the UAV community will also start using it. "

To all those reading this, click on the link, read the first page, its very clear. This is a FREE project for the benefit of our community.

Rjet, you have posted more false and untrue statements in than I care to go over again... Now all of us are entitled to SOME mistakes, but yours go way beyond that. What really tells what kind of person you are is how you respond when you find out you were in error. Do you step up like a man and admit where you were wrong in your posts, or do you try to hide your false statements and confuse the issue by posting further untruths ?

Your actions and posts speak volumes as to what kind of man you are.

[starcad]

For myself I think it's time to let this thread die guys.

[JettPilot]

JettPilot, 2nd rule of business is "Never knock anothers product when your trying to sell your own"

Your hurting yourself

You and rjet owe everyone, and especially myself an apology for posting false information and downright lieing about me selling a competing autopilot.


For myself I think it's time to let this thread die guys.


You made a very wrong and false statement... You jumped in and made a statement based on something rjet said, given that every fact rjet has posted in this thread is false, you should have known better than to parrot what he siad rather than taking the time to read the thread yourself. When the fact that you were mistaken was pointed out, instead of making it right, you now want it to go away.

I was brought up to always stand up for the truth, not just take easy way out and be "quiet". When im wrong, im man enough to admit it. As for you and rjet, your very public actions here speak volumes about what type of person you are.

[lvspark]

JettPilot,
We know that you are trying to develop a new autopilot to compete with the AP4, but please do not call people liars just to further your business.

Here is the thread of Jettpilot's autopilot project that he is trying to sell: http://www.rcgroups.com/forums/showthread.php?t=420499

Conflict of interest?

From what I have red here, jettpilot is not hiding anything, but providing his experience with the AP4 so others can make better informed decisions. I am sure if he has something to say or sell, he would just come out and say it.. He always does :D

If you push a particular autopilot based upon the mfg meeting you at the field (thats pretty nice), but that pretty much eliminates every other mfg that is to busy with business or lives out of town... I am glad you have good sucess with the AP4 and the customer service but it is possible for someone else to get the opposite results.

[rjet]

Your quote: "I was brought up to always stand up for the truth, not just take easy way out and be "quiet". When im wrong, im man enough to admit it. "

Then it is time to be a man and admit you are wrong, because you have already been proven wrong. Proof is something I have not seen in any of your postings, though that's not surprising.

1. Picopilots (with altitude feature) ARE sold for exactly $800 not "under". See www.u-nav.com/Price.htm
2. The AP4's PIC 16f876A's ARE reprogrammable not "rendered useless". See www.microchip.com
3. AP4 instructions ARE posted off ebay not "only an ebay ad" (and have been for several years). http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=6015454541

I could post many more of your statements here, but at least these are obviously provable as wrong.

Please check the facts before you attempt to discredit someone.

[clolson]

rjet,

JettPilot seemed to be complaining about the lack of any kind of support for the AP4 while the ebay add claimed great suppot. Rather than nitpicking each other's messages, why not just post the great support contact info and put this issue to rest? If you can't do that, then maybe JettPilot has a point to make. Seem's simple enough to me, no need for name calling here.

Curt.

[rjet]

Curt,
It seems Jettpilot has a few friends siding with him for whatever reason. I will look up some emails to post, but many of my personal meetings with him are undocumented (as are Jettpilot's experiences). If you take the time to read all the posts on this forum most of his buyer's were happy with the support and emails.

moon-dawg said "I sent many emails asking tech questions and EP92 got back to me in less than 24 hours. The item was shipped and received within 3 days of when I paid him."

You can even email him yourself if you have any doubts.

[JettPilot]

1. Picopilots (with altitude feature) ARE sold for exactly $800 not "under". See www.unav.com

Not True, $ 800.00 is for a complete SYSTEM that includes a 150 dollar GPS receiver and software ( 150 is what they charge for software if memory serves me...) If you buy the AUTOPILOT only (nav and alt boards) it is LESS than 800.00.

PICOPILOT-NA
NAV2, ALT3, GPS receiver and software CD
$800



2. The AP4's PIC 16f876A's ARE reprogrammable not "rendered useless". See www.microchip.com



The PIC 16f876A is a programmable chip, that has a security feature, if you try to download it, or modify the programming, it is ERASED, and all you have is an 8 dollar chip that now has no programming.

When a user asks if the autopilot is programmable, the answer is obviously no. A chip that has secruity protection to protect its programming on it is NOT programmable by the user. Programmable to a user does not mean having the entire contents of its programming erased as soon as you try to program it... Very bad and incorrect advice you have concerning this...




3. AP4 instructions ARE posted off ebay not "only an ebay ad" (and have been for several years). http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=6015454541




You are Correct: The instructions on ebay have a link to the address below with the insturctions to the AP4, and have been there for a long time...

http://plaza.ufl.edu/nuclear/ap4instr.html

My point exactly, there is NO contact information of any kind in the AP4 instructions. No phone, No name, No address, No email, NOTHING. The guy that sells the AP4 tells everyone that it is made in China, so that he does not ever have to support them. How can anyone claim support his product when he does not list ANY contact information of any kind ? I do not do business with liars and people that hide from their customers.

JettPilot

[rjet]

Yes, you are absolutely correct that his information is not on the AP4 instruction page. That is because it is on all his other webpages and made available through ebay to the buyers who have purchased autopilots from him. How could you possibly purchase from him without receiving this info? I do not do business with liars and people that hide from their customers either, which is why I chose not to use any other autopilot than the AP4.

[JettPilot]

That is because it is on all his other webpages and made available through ebay to the buyers who have purchased autopilots from him. How could you possibly purchase from him without receiving this info?

It is very easy to purchase something via Ebay using credit card / paypal without recieving their info....

I purchased one, and never got his info. So how about posting it here, I would like to know why he never answered my emails, and questions about my AP4.

An honest businessman has no reason to hide... Lets have the contact info..

[Hovertime]

Contact info is private/confidential, lets not forget that too guys.

Emails may get simply thrown out by spam filters way too often...

I wish he sold more of these things, I might get one in the future, but then with increased production prices will drop, as demand is relatively very low, which may not be in his best interest.

Open source, easy to do project would be ultimate solution, unfortunately we are not there yet.

[lvspark]

You could use the email at the bottom of this page for possible tech support...
http://xct.port5.com/index.html

from an email earlier in the year..
Mike,
Sure do. See my ebay auction: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5950674726

Best Regards,
John

Hi,
I emailed you a while back. Do you still make or sell those auto pilots?
Thanks,
Mike Myers
www.rsnw.com

[CRT_PJ]

What kind of support are you looking for? I don't think he is selling a product for aerospace or money making UAV applications. He is selling a toy for toy airplanes in my opinion. Some customers won't fit his expected profile. They will look for a more capable autopilot with support elswhere.

If the customer can't come to this conclusion by looking at the guys auction they didn't do any reasearch into autopilot systems, at all. Anyone that has a very capable product makes damn sure their website explains the full capabilities and shows that they can provide support for it.

I dont' understand the animosity toward EP92. Sure he's making good money on this item, but how is that different than anything else sold on ebay?

I buy my computers as some little place because they have good deals. If I wanted customer support I would buy HP or Apple, and gladly pay the difference. Some buy the components to build thier computer because they think they can do better than others.

[Medve]

My .02, I purchased an AP4 off Ebay. Being a novice at this, I had numerous questions of the seller, before and after the purchase. He always responded, some times with a bit of delay, with good information, and offered helpfull ideas. As I am not as technically versed as many, I can not comment on the technical side, but for product support, I have no complaints. If someone has a decent, competitive product it would be great to know. Not all of us can afford to fork out big bucks.