They are DEFINITELY not a scam!
I've bought around 20 Omega2+s. Some direct, some through Mouser. some through DigiKey and some through their Australian distributor Core Electronics.
My son has bought around 75 Omega2+s.
We've also bought several Omega2+-Dash units each.
Never a problem with ordering, delivery or support.
Thoroughly recommended.
Regards,
Dave
The data is in!
The Dash, working with networking running (UDP packets averaging about 2/sec), ran for 10hrs 55mins!
Of my two Dash units, this was the one with the slightly greater (i.e. "worse") drop across the switching regulator.
That's using a 2600maHr LiPo which I measured at 2400maHrs (average temp 15deg hence the approx 10% degradation).
3.3V was maintained until 1hr before the end whereupon it slowly dropped until the Omega stopped working and the LiPo protection circuit had not yet kicked in.
Drop across the switching regulator was 120mV for the last hour. This was slightly higher than the 108.5mV I measured with the regulated power supply.
So a Dash with a better LiPo or with two LiPos gives (in my opinion) excellent battery life for mobile projects.
Best Regards,
Dave
Okay, I've answered my own question and provide further information which might be useful to some.
I've checked the schematics (kudos to Onion for publishing them). I can confirm the display runs off 3.3V.
5V from the USB in goes via the on/off switch to a DC-DC converter which powers the whole unit. The converter is rated at up to 1amp.
Current drain of the Dash is very modest, averaging 240mA at 3.3V or 792mW. Power drain is slightly higher at the 5V input but current draw is lower because the converter is quite efficient. Above power figures are with the Omega2S doing frequent network and screen activity. Of course, as with all the Omegas, there can be short current peaks which are higher.
I examined the schematic of the voltage converter and there should be no problem applying 3.3V (e.g. from another power source) to its output. The bottom FET of the totem pole output will be turned off. It is possible the top FET will turn on because of effective negative gate voltage. However, all this will do is partially connect the large (400+ uF) capacitor to the output, which is a good thing for handling short current peaks.
I have been successfully running one of my Dash units direct from 3.3V applied to the header. For over 24hrs without a glitch. I needed to use a 68uF capacitor across the header as otherwise long lead inductance to my power supply was a problem.
I take no responsibility for any similar experiments you might perform. Onion might even deem it a void of warranty but I hope not.
The big plus is that it makes it easier to build a hand held device that can be run and/or recharged by USB. I'm putting at least one Dash unit into a box with a 3.7V 18650 LiPo cell running it via a 1A 3.3V LDO regulator direct (via an/off switch on the box) to the Dash header. The 18650 will be supplied by a cheap Li battery charger with inbuilt low voltage cell protection.
I'll update the forum when I've built this "in the real world".
Regds,
Dave
Thanks Lazar and also to crispyoz for the lsof info.
Project is finished but not yet in a box. I'm investigating battery power/charging for it and will report back when the whole thing is done.
I'm actually using it now but with the Dash hanging off the end of a USB cable.
Cheers,
Dave
Hi, why don't you buy an Omega2-Dash? It comes with a 320x240 touch screen integrated with an Omega2S+. LVGL is provided for doing GUI etc.
Cheers,
Dave
Here is a pic of one of my Omega2-Dash units connected to a Ti TP4056 based charger/protection board.
LiPo connected to +_ battery terminals.
Load out connected to Dash 5V/Gnd with 68uF tantalum. 5V switch on Dash set OFF
Charges via USB input on TP4056 board. Battery under voltage protection. TP4056 cuts charge when complete (PROVIDED the Dash does not stay powered up) else it "floats" which is bad for LiPo life.
I'm doing a test to see if I do indeed get the extra 30mins run time compared with the linear regulator (which gave over 9hrs).
Cheers,
Dave
Okay. My 2600mahr LiPo ran the Dash for just over 9 hours. The LiPo was at an average of 15degC which derates the capacity to 2400mahrs. So I would expect 10hrs, so just over 9hrs is not too bad. The reason for the discrepancy is that the tail of the LiPo discharge cannot be used because the LDO cutout is about 0.1volts, so when the LiPo hits <3.4V the Omega2+ starts to misbehave. Total consumed energy was 8watthrs and "wasted" energy 0.86watthrs.
You could expect 24hrs continuous running with 2 high quality 18650 LiPos having higher AH rating.
Hopefully this is useful information for people contemplating putting the Omega2+Dash into portable applications.
Regards,
Dave
Thanks Lazar.
Good tosee the swift action.
In my case, I'm running off LiPo via an LDO regulator directly to the 3.3V input so not using the USB input on the Dashs.
I determined that 3.3V can be connected to the secondary of the switching regulator used on the Dash with no problem (when no USB power connected). At worst, the top FET in the regulator will turn on, connecting some extra capacitance across the output- which is a good thing should it happen.
Regds,
Dave
Ah yes. I have one too! This is from the mid 1960s.
I was studying Electrical Engineering and during one vacation was working at what was called the "Postmaster General's Department" in Australia (they had provided me with a scholarship). In other words, Posts and Telegraphs encompassing communications such as TV, phones and even the ordinary mail.
Anyway, my boss, the Chief Engineer decided to give me some field experience. So I went to a facility high in the mountains. It was a sort of relay station for microwave links between Sydney and Melbourne. Very important as it (as well as TV) carried all telex, phone calls etc between capital cities.
The local engineer showed me the various workings, including the triple redundancy with lots of stuff. He proudly opened one rack with multiple power supplies and various transmitters & receivers.
I said "So, if any one of these rack units fails, another one will automatically take its place?" "Yes" he replied.
"Can I try it?"
"Sure".
So I did. I pulled out one of the rack units and all was good.
Then I tried to put it back in and somehow got things crooked and pushed way too hard (I was a strong guy).
There was a huge "bang". A huge flash. Sparks flew everywhere.
Then- dead silence. All dead. Everything dead (except the humans)! It was pitch black (no windows in there).
After one minute's silence (during which I was seriously considering if I had any future), a couple of dim light bulbs came on. Then all seven bright red phones started ringing. Then a huge (about 100kW) generator started up. Then various lights came on.
I had wiped out everything. But they got telephones, telex and stuff going in about 10mins. But Television took until next day.
That was the end of my work experience in the field. The rest of the time, I was confined to HQ with a drawing board updating diagrams!
Like the molten steel-never forgotten.
Also, I learned something about systems which allegedly can never fail......
Regds,
Dave
I assume you are running from a 3.7V cell as well as trying a 5V power supply?
One other thing. What package LM3940 are you using? I used a TO220 with no heatsink (as you will have seen in the photo), which was fine. On some of my other projects I am using SMD LM3940s from 5V to 3.3V with Omega2+ and Omega2. They definitely need heat-sinking or they will heat up and then likely shut down after a while.
Let us know how you go.
Regds,
Dave
@CAP-33 , have you checked the output voltage and monitored it when the Omega2 fails the boot process?
What is your power supply ? Can it supply enough current?
Do you have a 0.47uF input capacitor on the LM3940?
Regds,
Dave
That is true.
However, for my (several) applications, I find it to be great. I'm sure that many others will find the same.
I have a number of low power applications using Omegas. However what I do is run an ultra low power PIC processor, which wakes up from time to time and fires up the Omega (and ancillary devices, in sequence) and communicates with them before then shutting them (and DC-DC inverters) down. They run with several high efficiency DC-DC converters and consume a tiny amount of power on a daily basis. I would like the Omegas to boot a bit faster, but overall this scheme works well. I cannot conceive the Omega having a sleep consumption of well under one microamp to match a PIC or similar microcontroller.
The Dash is the same philosophy as the 4D systems people have had for some years (smart displays). However, it is cheaper and more powerful and more general. The 4DGL units have more powerful graphics, some sleep options and you can programmatically turn off their display, but I like the fact that the Dash is the computer as well as the display.
Cheers,
Dave
Okay, here's a little more information. I have measured my LM3940 and the voltage drop is only 90mV. So better than the worst case spec.
See thread
https://community.onion.io/topic/4170/omega2-dash-5v-and-3-3v/6
If powering an Omega2-Dash, you can use the onboard switching regulator and this saves a further 15mA of drain and (in my case) should add an extra 30mins of battery life.
You could use the OmegaDash switching regulator (or similar) with a normal Omega2 or S because it is LDO (Low Drop Out) but it is more components and cost. So if I was adding extra circuitry and a PCB to a portable Omega2 device, I'd use the switching reg but if only supply power I'd use a LM3940 (or similar) LDO linear regulator.
So, for my Omega-Dash units, I'm using the onboard 5V input fed from the TP4056 and the LiPo connected to the TP4056. Charging from the TP4056 USB/5V input.
I've gone back and corrected the 2940s to 3940.
Regds,
Dave
I am so sorry- my old (73 year old) eyes are not so good any more. They are LM3940; I misread the 3 for a 2 but had the correct datasheet and did not look closely at the 2/3.
The voltage differential is 0.110V at 100ma and 0.5V at 1amp. However at around 240ma the differential is about 120mV. The capacitors absorb any surges (e.g. from the WiFi). So you still get 3.3V out until the LiPo drops to 3.42V. The Omega starts to misbehave below about 3.2V, depending upon production spread.
Regds,
Dave
Edit: I also suggest looking at Texas Instruments or National Semiconductor datasheets rather than generics.
Hi Cap33,
Glad you solved you problem. Good also that your Omega presumably still works after direct connecting the LiPo cell. However, if you are using a single 3.7V LiPo the input voltage is out of spec (too low) for the LM2596. LM2596 would be fine from about 4.75V upwards (so USB 5V, 12V et al). So if it works then that is more by good luck than anything else. Also a more expensive solution than a cheap LDO linear regulator.
Regds,
Dave
Okay, to illustrate (for anyone wanting to run off a LiPo cell), I quickly knocked up a Lipo with LM3940 regulator. Works fine with the attached Omega2Dash doing WiFi networking over 2 UDP sockets once per second plus running an App I've made with LVGL. Here are some photos.
The LM3940 has a 0.47uF ceramic on the input and a 68uF tantalum on the output. In this case, it is driving the Omega2+S plus the Dash display. I have a separate post about connecting to this part of the circuitry (search for 3.3V and 5V and Dash). Cost A$1.80or US$1.00.
The small PCB is a TP4056 based LiPo protection and charger board. Cost A$2.40 or US$1.40.
This cell should run the Omega-Dash for around 10hrs.
Regds,
Dave
Edit: Corrected incorrect LM2940 to LM3940
I am running five different Omega2+s off 3.3V 1A SMD regulators. You need to supply brief peaks of current for the WiFi. But the average is less than 300mA. Well within the capability of a LiPo 18650 or a couple in parallel.
I also have two Omega2+ Dashs and they are running just fine off a TO220 LM3940 and are drawing 240mA average at 3.3V.
I have a couple of other Omega2+s running off 12v:3.3v 1A Texas Buck converters. All good. The Omega2+ Dash from the factory uses a 5:3.3 switching regulator rated at 1A when running off USB.
So, I see no problem using a single 18650 LiPo through a LM3940 1A LDO regulator. Just add a couple of capacitors per the LM3940 datasheet and I'd also add around 100uF ceramic or tantalum at the input of the Omega2+. There is no point using a switching regulator given the LiPo will be operating between about 3.2 and 4.2V (the latter briefly). Make sure to have LiPo protection either in the cell or in the charging.
Regds,
Dave
Edit: Corrected incorrect LM2940 to LM3940
I looked up the Absolute maximum Voltage specification for the processor used in the Omega2+.
It is 3.63V.
So, anyone connecting a nominal 3.7V LiPo is playing with fire. Depending upon state of charge and temperature, the Absolute Maximum ratings of the processor will almost certainly be exceeded. By a small amount at 3.7V and by a large amount at voltages exceeding that.
So, why blow up or damage a device or make it unreliable when the proper solution is so cheap and simple?
Regards,
Dave
I would not run without a regulator. LiPo can also be 4.2V if just off a charger. That exceeds specs and would almost certainly blow something.
Cost of a TO220 (or similar SMD) 2940 regulator (rated at 1amp) and a couple of capacitors is US$1.50 or 2 euros.
It's not worth risking damage to save such a small amount of money and circuitry.
Regds,
Dave
Use a LM2940- 3.3V- LDO (lowdropout) regulator.
Datasheet will show what capacitors you need.
Simple, cheap solution.
Regds,
Dave