Forum >Replies by alnath
Replies （15）
- You Reply: sure !
I didn't tell to use a 7809, I was just saying that 9V were not necessary , if you power the arduino using the jack plug (thus through the internal 5V regulator), 7.5V are enough .
There are several solutions :
- 7808 , 7809 ... easy and cheap, but power wasted in heat
- DC-DC module, output 7<- > 9V : no external waste or heat, but still waste in the arduino reg. ... expensive ?
- DC-DC module output 5V direct to Vin : no waste or heat ... more expensive ? - You Reply: [quote="Sly"]
Problem is, I need gprs/gps shield and it has recommended 9V power supply. While almost all power banks supplying usb 5V connection only. I've found universal power bank that can output 9V, but it costs over $80, which is overkill for me.
Any ideas?
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When you power the arduino board using the jack plug, it goes to th input of the internal regulator, which outputs 5V ! Then no need to come with 9V -
Actually, GPS/GPRS shield doesn't need that your power supply is 9V mini... what is important is that it can deliver more than 2A (not for a long time though ;) ) , especially at startup, when the GSM connects to the network, and sometimes, when receiving/emitting calls/SMS .
As the internal regulator needs minimum 2V between its input and the output (5** -> 7Vminimum), they say 9V .... to be sure that, if the power supply voltage drops during bursts , it will still be over 7V ;)
So don't worry , I've tried with 7809 and 7808 external regulators, connecting the output to the jack plug of arduino, and, as long as my battery pack gives enough, everything works well .
I think that you could use an external 5V (well regulated !!) power supply and connect it to Vin , but....make sure it is a good 5V and not more than 5V - You Reply: Yes, it would work, but, even if it can support it, the 12volts output is a bit too high for your arduino. The internal regulator will get hot, especially if you use the GPS/GPRS shield ;)
I would use this one [url=https://www.dfrobot.com/index.php?route=product/product&path=70_119&product_id=752#.UfKJTEnnOxU]https://www.dfrobot.com/index.php?route=product/product&path=70_119&product_id=752#.UfKJTEnnOxU[/url]
ok, it is not waterproof, but I guess it doesn't rain in your car :P , and you can adjust the output value. Then if you adjust it to be 9 volts, eveything will be OK - Topic: I2C 1602 LCD not workingYou Reply: it seems to me that it is a contrast adjustment problem
- Topic: I2C 1602 LCD not workingYou Reply: it seems to me that it is a contrast adjustment problem
- You Reply: Hi,
I don't use or even know romeo, but it seems that you reverse the direction staying at full speed... maybe the motors don't like it ? what if you try to stop them with a sequence like this :Code: Select allbefore reversing the directionanalogWrite (E1,0); analogWrite (E2,0); delay(200); // ajust as needed
it would give more time to the motors
my 2 cents ;D
jf - You Reply: Hi I know it's a little tricky to understand, because I had a little "fight " with it too, but when you get it, it becomes clear....but not so easy to explain First of all, I insist on the fact that, for the testing parts of the wiki, you must do what is told at the beginning of the examples ! In your case (you want to test the GPS part) :Code: Select allI'm not sure about the "//# 2." , but I think that I had it on the USB side when I tried the examples Then if you launch the sketch, you'll see the messages on your terminal
// # Steps: // # 1. Turn the S1 switch to the Prog(right side) // # 2. Turn the S2 switch to the Arduino side(left side) [color=red] // oups, I think I put it the other side (usb) !?[/color] // # 3. Take off the GSM/GPS jumper caps from the Uart select // # 4. Upload the sketch to the Arduino board // # 5. Turn the S1 switch to the comm(left side) // # [b]6. Plug the jumper caps back to GPS side[/b] // # 7. RST the board
Once you've checked the GPS part, you can try the example for the GSM part, but the point "6" above is "Plug the jumper back to the GSM side"
If you dont' want to interact with the module from the PC, the switches must be put like this :
- center the uart switch
- S2 on "arduino"
- S1 on "com"
In this case, the module obeys to the AT commands : you can't send it commands from the terminal, and the messages from GPS/GSM won't appear either.
But you can see the commands that your sketch sends : they'll arrive both on the terminal and the module !!
In fact, the module communicates withe the GSM part and the GPS part using the same serial pins, that is why the AT commands are importants :
digitalWrite(3,LOW);
digitalWrite(4, HIGH);
tells the module to communicate with the GSM part ! The GPS sends the messages, but th module just don't get them.
And
digitalWrite(3,HIGH);
digitalWrite(4, LOW);
tells the module to communicate with the GPS part. Ih this case, the GSM messages are not seen.
I hope (but I'm not sure) it helps a little To summarize :
- If you want to try and interact with the module from your PC, then, copy/paste the examples of the wiki, and don't forget the switches manipulations described at the beginning of each sketch.
- If you want it to run by itself, you don't play with the switches and put them as I told above. Don't forget that the module communicates with one part or the other one depending of the pin 3 and pin 4 values . It's up to you to put the module in GPS or GSM mode (and give it 2 seconds) before sending/receiving messages to/from the part you want. And keep in mind that, in this last configuration, if you run the terminal, you'll see only the messages that your sketch sends.
Don't hesitate if you need precisions, even MP is OK - I had some headaches too at the beginning, but now, mine is doing exactly what I want it to do
jf
PS : As Jose told you before, if you want to use the GSM part, an external power supply is needed !! It won't work with the USB supply alone - Then if you want to see the GSM messages on your PC, you need to connect both the usb cable and an external power supply (9V 500mA is enough it takes about 250mA when it starts, but no more) - You Reply: Hello
Jose is right, it's necessary tu put the whole code. Because here, we have to guess.... if you put the lines :Code: Select allthese lines are needed for the GPS to send messages to the module .digitalWrite(4,LOW);//Enable GPS mode digitalWrite(3,HIGH);//Disable GSM mode delay(1500); //stabilisaton mode GPS
then, when you want to communicate with the GSM part, you put :Code: Select allwich allow you to read/send messages to the GSM part .digitalWrite(3,LOW);//Enable the GSM mode digitalWrite(4,HIGH);//Disable the GPS mode delay(1500);
You also need to check that the switches are OK :
- center the uart switch
- S2 on "arduino"
- S1 on "com"
HTH,
jf - You Reply: my pleasure :)
I'm happy when I get help, and even more if I can help.
Yes, it's OK to invert 3 and 4 , but some AT commands, even "GPS related", only give an answer when in GSM mode (i.e. CGPSSTATUS? , CGPSPWR....) .
For my project, it's OK , I swith to GPS mode only when I need to get the position, and back to GSM mode as soon as the GPGGA (or whichever sentence I need) sentence is received. - You Reply: thank you Phoebe,
LOL, I wish I were ;D
sometimes, it's a little tricky
anyway, I understand a little more every day how it works, and I'll try to post tips and/or ideas if I think they could help . - You Reply: Hello,
have a look here, page p.139 [url=http://www.simcom.us/act_admin/supportfile/SIM908_AT%20Command%20Manual_V1.01.pdf]http://www.simcom.us/act_admin/supportfile/SIM908_AT%20Command%20Manual_V1.01.pdf[/url]
hth, - Topic: GPS/GPRS/GSM Shield 3.0You Reply: try to use an external power supply, I think it will work :)
- You Reply: Hi again :)
For the last question, the answer is here [url=http://www.simcom.us/act_admin/supportfile/SIM908_AT%20Command%20Manual_V1.01.pdf]http://www.simcom.us/act_admin/supportfile/SIM908_AT%20Command%20Manual_V1.01.pdf[/url] p.224 :)
maybe it could help other members :)
still need answers for the previous questions ;) - You Reply: [quote="Phoebe"]
[quote="blue_sky"]
HI Phoebe,
What do you mean by jumper caps? There are no jumpers as far as I can see for the UART. There is a switch for the UART with three positions - GPS, center and GSM?
Could you please clarify this?
Thank you.
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Two jumper caps in the bottom right corner... ???
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No, there are no more caps besides the leds, the last version comes with a 3 position switch :
Left for GSM, Right for GPS and the central position.
The, instead of removing the caps, I guess you could put the switch in the central position ;) - You Reply: OK, never mind, when I use the same AT commands in a sketch, everything works well, the sms is OK