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The Eggtimer Apogee - A Very Simple Apogee-Deployment Altimeter

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H. Craig Miller

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For those of you that want to use the Mini Switch (WiFi) to turn on the Apogee altimeter, Cris of Eggtimer Rocketry was kind enough to provide a wiring diagram.

Mini Switch WiFi.05.Battery.jpgMini Switch WiFi.05.Battery.jpgEggtimer Mini Switch to 1S-Powered Altimeter Drawing.png

The Mini Switch uses a 2S battery. The Apogee altimeter uses a 1S battery. So, the above special wiring is required to use the two together. If your altimeter has switch inputs (such as the Apogee screw switch), the inputs need to be shorted.

CAUTION: If you power the Apogee altimeter with a 2S battery, you WILL damage the Apogee altimeter.
 
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Kelly

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The Mini Switch uses a 2S battery. The Apogee altimeter uses a 1S battery. So, the above special wiring is required to use the two together.
To get the 1S you need for the Apogee, couldn't you also splice into the charging leads on the 2S battery and grab a 1S connection? This would eliminate the need for a 1S battery if you were really trying to save weight/space.
 

ajward

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To get the 1S you need for the Apogee, couldn't you also splice into the charging leads on the 2S battery and grab a 1S connection? This would eliminate the need for a 1S battery if you were really trying to save weight/space.
you could in theory take the power from a single cell of a multi cell battery through the balance port. You just have to be aware you are then intentionally unevenly discharging it.
 

ajward

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The split voltage connection (the balance port) on a 2S battery is negative. Because the Mini Switch also breaks the negative connection, this method does not appear to be a viable option.
Yes, but if you wire it like the diagram above, using the negative from the switch then use just the positive from the first cell (you just have to be careful not to take the positive from the second cell otherwise you will get full voltage) on the balance port to power the apogee it should work.
 
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ajward

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There is no positive connection from only one (or the first) cell in a balance port connector. There is one positive wire, and one negative wire times the number of cells. So, in a 2S battery the balance port connector has 1 red (positive) wire and 2 black (negative) wires.

That said, a 2S battery is two batteries in series, so if you attach to both black wires, you will be attaching to only one cell (effectively a 1S battery) with one black wire being positive and the other black wire being negative. But, as mentioned above, you will be discharging LiPo cells at different rates (I’ll leave it to battery experts to weigh in on the risks associated with doing so).

Not everything that can be done should be done.
It's the other way round on balance plugs there is a negative attached to the negative of the first cell, then there is a positive attached to the positive side of each cell. (i have check this with the cells i have using a multimeter)

so it should definitely be possible to power it this way and it is a trick that is used for example to power low draw lighting circuits in rc planes. weather its a good idea is another question.
 

H. Craig Miller

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My original post was intended to provide the Forum members with information obtained from the manufacturer, not to create controversy or contention. I was simply trying to be helpful.

To clarify and be more complete as to the balance port on a 2S LiPo battery, I will use the picture below.

C4DCF01D-0A70-4B59-985B-50432610A459.jpeg

The balance port connector is the one with three wires (the only visible connector on the left). To connect to only one cell, you can either connect to the red (positive) and blue (for negative) OR the blue (for positive) and black (negative). Testing either with a volt meter should be about 4 volts with a fully charged 2S battery.

I will leave it to those more knowledgeable than me to comment on the risks and benefits of unevenly discharging the cells of a 2S LiPo battery. But, the schematic provided by Cris is likely the best/safest method; it is unlikely that any manufacturer (including Eggtimer Rocketry) would assume the liability of recommending the use of a LiPo battery in a manner that is inconsistent with the battery manufacturer’s intended use.

Really nothing more to say... either follow the instructions of the manufacturer of the Mini Switch and Apogee altimeter, or don’t.

Good luck with it.
 
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MikeyDSlagle

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For those of you that want to use the Mini Switch (WiFi) to turn on the Apogee altimeter, Cris of Eggtimer Rocketry was kind enough to provide a wiring diagram.

View attachment 435948View attachment 435949View attachment 435950

The Mini Switch uses a 2S battery. The Apogee altimeter uses a 1S battery. So, the above special wiring is required to use the two together. If your altimeter has switch inputs (such as the Apogee screw switch), the inputs need to be shorted.

CAUTION: If you power the Apogee altimeter with a 2S battery, you WILL damage the Apogee altimeter.
Well thank you for the diagram. I had thought of using it with the Mini Switch in some setups. This will prevent me from toasting the Apogee.

Mine is currently somewhere along the Kessel Run. "It is currently in transit to the next facility" again. It could end up in Shreveport, LA; Jackson, MS; back in Memphis, TN; or even Iowa. No telling. The order I made back in August was here in 4 days.

Nothing against Cris or Eggtimer. Just a little light humor at the expense of USPS.
 
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H. Craig Miller

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This is an informational post for those Forum members who are assembling a Mini Switch (WiFi). One of the most difficult steps that I found was trying to identify the correct orientation of the LEDs. Although I found that my iPhone camera was able to magnify the LED enough to see the chamfered corner, I also observed that the chamfered corner is on the same end as the large window (within which you can see a small square); the small window is not the small square referred to in the instructions. You can see this large window with the naked eye, rather than trying to see the chamfered corner or small square with a loupe or other magnifier.

See Below:

Mini Switch WiFi.06.LED.Marked.jpg


Hope this is helpful.
 
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cerving

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you could in theory take the power from a single cell of a multi cell battery through the balance port. You just have to be aware you are then intentionally unevenly discharging it.
Yes, but you need to be careful that the NEGATIVE sides are common. The Apogee draws so little current that I wouldn't worry about uneven discharge.
 

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Will a balancing charger charge the apogee 1s battery?
 

cerving

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Yes, IF you adapt the connector, AND you limit the charging current to no more than 200 mA. FYI, we now sell the little micro-USB chargers for the 110 mAH batteries... they're $8. They charge at 100 mA. Like the batteries, we're not really making anything on them... we're basically carrying them as a service so you don't have to pay extra postage to somebody else to get them.
 

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I have just had a batch of Egg stuff turn up on my doorstep. I find no need to cast nasturtiums at USPS. Seems to made it here well. Packing was great so it survived both USPS and OzPost. Thanks Cris. :)
 

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Heeeyyy. Mine showed up today. Yippee.
Now all I gotta do is patch the roof, fix the lawnmower, finish cleaning up after two hurricanes and rebuild a lawnmower shed...then I can do some rocket stuff.
 

cerving

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Ahh, just build the Apogees. It's too early for rain, the grass is pretty much not growing anymore, and there will probably be another hurricane anyway.
 

Michael L

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Heeeyyy. Mine showed up today. Yippee.
Now all I gotta do is patch the roof, fix the lawnmower, finish cleaning up after two hurricanes and rebuild a lawnmower shed...then I can do some rocket stuff.
Mine too. I'm almost positive that I'm a trust fund baby... I'm not sure why it's taking so long to pay off. I guess I'll work all week and build this coming weekend :)
 

cerving

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FYI, I've posted a preliminary (i.e. not quite complete) version of the assembly guide for the Easy Mount. It's missing pictures for an installation using the internal mounting ring, which you would use for a fiberglass bulkplate mount vs. just screwing it into a plastic nose cone or wood bulkplate. I should have a final version in a day or two, in the meantime the preliminary version should give those of you who just got one a pretty good idea of how it goes together.
 

MikeyDSlagle

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Ahh, just build the Apogees. It's too early for rain, the grass is pretty much not growing anymore, and there will probably be another hurricane anyway.
LOL
Too early for rain...
Silly Californian, this is Lousiana. It's 50/50 everyday. 100% tomorrow.
And there is a hurricane in the gulf. Lol.
I'm cleaning up for a Halloween weenie roast, and I can't stand for my yard to look like it does.

These things will go together fairly quickly. I shoulda ordered more as I imagine I will fly them A LOT!

a little tangent:
Hurricane Laura hit us HARD. The eye came right over my house. 2 weeks without power. I still have a transformer pole in my yard. Some still without power, over 700,000 without power initially. It was 95 in my house, with 85% humidity. We are still cleaning up. I have a piles of tree debris along my road that is effectively a privacy fence. Our governor said it "wasnt that destructive", only because it hit rural communities and not New Orleans. 2 people died in the storm, 20+ after from heatstroke and CO poisoning.
 

cerving

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Wow, I think I'll take my chances on the occasional, if unpredictable, earthquakes we have here...
 

boatgeek

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Wow, I think I'll take my chances on the occasional, if unpredictable, earthquakes we have here...
I'm with you. I don't want to see my natural disasters coming. 😀 I was in the office when our last medium earthquake (~6.5) hit the Seattle area. I remember thinking that I was glad that we were on the top floor, because we'd be on the top of the rubble heap. The building was fine in the end, but it sure swayed around a lot.
 

Michael L

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I have a self imposed rule of "no soldering circuit boards after 9pm" (because I usually screw them up if I work that late) but I broke the rule and soldered the Eggtimer Apogee board and tested it last night starting at a little after 9 and finishing at 9:30-ish. I did the first test in the manual, I'll plug in the serial and check that this evening). It's an easy to assemble board. The single SMD is easy enough to install since it's a 1206 component. I used my Hakko to solder the nut for the switch to the board and the smallest tip I have for the Weller station (because that's what is in the iron) for everything else.

It's a nice, simple kit with good instructions. Nicely done Cris
 

Michael L

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This is an informational post for those Forum members who are assembling a Mini Switch (WiFi). One of the most difficult steps that I found was trying to identify the correct orientation of the LEDs. Although I found that my iPhone camera was able to magnify the LED enough to see the chamfered corner, I also observed that the chamfered corner is on the same end as the large window (within which you can see a small square); the small window is not the small square referred to in the instructions. You can see this large window with the naked eye, rather than trying to see the chamfered corner or small square with a loupe or other magnifier.

See Below:

View attachment 436088

Hope this is helpful.
I don't know if this is the "right" way to do it but I usually flip the Fluke to Ohms and measure across the LED. When it lights I have my polarity... or it flips into whatever dimension SMD parts live.
 

MikeyDSlagle

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I have a self imposed rule of "no soldering circuit boards after 9pm" (because I usually screw them up if I work that late) but I broke the rule and soldered the Eggtimer Apogee board and tested it last night starting at a little after 9 and finishing at 9:30-ish. I did the first test in the manual, I'll plug in the serial and check that this evening). It's an easy to assemble board. The single SMD is easy enough to install since it's a 1206 component. I used my Hakko to solder the nut for the switch to the board and the smallest tip I have for the Weller station (because that's what is in the iron) for everything else.

It's a nice, simple kit with good instructions. Nicely done Cris
I assembled mine last night as well. Started about 830 and finished around 930. Since I had my station out I went ahead and did both. I was near finished with the first one when I decided to look at instructions and realized the nut to the screw switch was pretty much the first thing to do. The second one I did the nut first, then "chips", then all the through-hole at once. Went together a lot more quickly. The only SMT part was the only part I dropped.

Will do a vac test when I get time.

@cerving ..Cris does the Apogee transmit real time data via the header like most of your others?
And will it operate from a 3.3V or 5V source? Such as a small step-down regulator. I have a board designed (if I can locate it again) to take power from a 2S or 3S and step it down to 5 volts to power a 3DR radio. Just curious if it would run the Apogee.

*edit..
Just went back and read the battery portion of the users manual.
Pretty much 3.6v - 4.2v
Think that is my answer.
 

High Desert Rocketry

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Just put together one of my Apogees while Cris was talking on episode #99 of the Rocketry Show last night. By far one of the easiest kits Eggtimer makes and one I'll be recommending the students I mentor to get as their first soldering project and or as an inexpensive apogee deployment backup for other flight computers. Will be flight testing it and an Eggfinder next week at FAR.
Seems like a perfect way to get into electronics for Level1 and 2.
I am assuming a two screw terminal block fits in the output area though I may just solder in two stranded wires as recommended.

apogee kit ed.png
 
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MikeyDSlagle

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I redesigned my pancake bay for the Apogee
Needs a little more fitting and tuning. I intended to make the battery connector sit upwards so it would be easier to charge the battery. As it is now the Apogee has to be removed to unhook the battery. Less than 1.25" tall not counting the charge well. Made to sit on the motor mount of a fiberglass 2.6" lil Goblin and 2.6" V2. Has a matching ring to slide down the outside for drilling holes.
pancake bay  (1).jpgpancake bay  (2).jpg
Brass knurl nuts are for connecting the ematch of course; on the inside the wires are connected to ring terminals and attached to the screws holding the charge well in place. Charge well is replaceable.
 

cerving

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Nice mount! We went with a vertical orientation for the Easy Mount... it will fit into a 38mm coupler.

BTW, we still have quite a few Apogees in stock, along with the Easy Mount/battery/USB charger.
 
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