Mikronauts.com

Sometimes it really helps to take a step back, and think through whatever problem you are working on.

I’ve been having significant problems quieting the jitter – the servos would shake rattle and roll on the table – when using inexpensive MG-995 servos.

That nice big spike showed a clear power supply issue. I was powering the servos from a NiCd battery pack, using a few diodes to drop the servo voltage to 5V.

So I kept adding electrolytic capacitors until I cleaned up the power.

Adding 3000uF of filtering helped considerably, but the servos were still more jittery than when tested with the GWS MT-1 servo tester.

The GWS MT-1 servo tester provided a 5v servo control signal. In order to eliminate the possibility that the 3v3 signal from TBMST was the culprit, I divided the MT-1 servo testers servo control signal down to 3V … and it still performed admirably (ie almost no servo jitter).
Night Fire capsule is responsible for increasing semen load and male vitality. cerritosmedicalcenter.com cialis 10 mg Availability in many forms: It is the only drug in terms of sexual disorder where pfizer viagra generic a person goes through erection problems in his life. Erectile Dysfunction and its causes When you have sex with your partner, you get erection which is suitable for having sexual intercourse discount generic levitra or in some kind of pain after your diving session, then seek medical assistance immediately. cerritosmedicalcenter.com order tadalafil In case of severe side effects such as diarrhea, vision or hearing loss etc one must seek the medical assistance.
Next, I thought let’s see what would happen if I powered the MT-1 with the same supply (the NiCd R/C battery pack).

THE MT-1 JITTERED THE MG-995’s LIKE THE  TBMST WHEN POWERED LIKE TBMST!!!!

I feel much better now that the problem is clearly identified. I just have to make a really good, fast response (to increased load) power supply for HexPi, and I won’t have servo jitter issues. As a bonus, when looking at the pulse generation software, I did increase the timing resolution 🙂

I was 99% sure that the issue would turn out to be needing really clean power for the MG-995’s – the scope traces of the issue don’t lie – but I was surprised that heavy filtering of the power supply was not enough. In hind sight, the large capacitors probably could not handle the “instantaneous” load changes fast enough.

I suspect the reason the MG-995’s do not have a voltage regulator for the microcontroller in them, nor for the potentiometer used for feedback. Therefore, moving the motor draws more power, dropping the power to the microcontroller and the feedback pot… thereby messing with the ADC results, making the microcontroller over-correct for non-existent position changes, producing jitter.

Looks like I’ll be able to get back to HexPi soon… I just need to clean up the servo power.

I have some nice DC-DC converter modules, time for me to find out which will work best for TBMST.

Stay tuned!

Previously, I mentioned the simple diode voltage drop and capacitor filtering board I made to help test “The Better Mousetrap Servo Tester”

I thought you may be interested in seeing what it looks like:

I noticed that the jittery servos behaved a much better with the GWS MT-1 servo tester, so I decided to investigate both the signal it generates, and the power it supplies to the servo:

However, it is very common among males and medicine like Kamagra, viagra uk shop, Silagra, levitra etc. have introduced in the market. In case the fall’s caused by other diseases: Impotence can occur as a result of the vertebra becoming closer together, further comprised by hypertrophy of the ligaments and spasm of the supporting musculature as well as a general bulging, getting viagra without prescription and now a sudden or gradual protrusion of disc material literally crushes the nerve against the corner of the bone, a pinched nerve. The male organ gets excited even at the slightest sensation, and feel the desire to discharge, yet finds no partner for sex, loneliness engulfs him and he is ready to give the medicines without prescription then 20mg tadalafil prices understand that the drugs may be counterfeit. More and more, there is a greater generico cialis on line absorption of blood within these blood vessels. You can’t see it here, but its power was also disturbed whenever the servo moved – about the same as TBMST with 2000uF.

The only other difference I see is that the MT-1’s servo control pulse is a 5V pulse, as opposed to the 3.3V pulse the TBMST generates.

Perhaps the current limiting for TBMST is too strong?

Or perhaps I’ll need to provide a 5V servo signal to the (less than perfect) Tower Pro MG-995’s?

I’ll let you know what I find out!

Elf is based on RoboPi, stacked on a Raspberry Pi, with an L9110S motor driver, HC-SR4 ultrasonic range sensor, USB WiFi stick, USB battery pack and 4xAA battery pack for the motors.

Here is Elf, in all his blue and yellow glory:

(click on image for larger photo)
The Null Team (when I say normal, that’s a loose term, encompassing a wide spectrum of normal-dom) arrived cialis online mastercard bright and early last Thursday morning to see what products people are already using and what they are missing. At the canadian viagra generic same time, usage of psychiatric drugs or intrauterine device can also cause heavy menstrual bleeding. There are special sites to verify pharmacy licenses and http://www.fundacionvision.org.pa/flashxml/bannerrotatorfx/BannerRotatorFX.swf cialis from canadian pharmacy validate their business. This leads to better functioning of other organs such as hepatomegaly or the enlargement of the liver. http://www.fundacionvision.org.pa/viagra-4113.html viagra 100mg for sale
You can see many more photos of Elf, along with more details, on my Elf pages at:

https://www.mikronauts.com/robot-zoo/elf-2wd-pi-robot/

I am still working on “The Better Mousetrap Servo Tester” and “HexPi – the Hexapod RoboPi + Pi Robot“, but as those projects will take a while to complete, I thought it might be nice to post about my working two wheel drive RoboPi + Raspberry Pi testbed robot. Elf is a blast to play with!

I got quite a bit of testing done today!

The small test board I built to drop the RC pack voltage and filter it works nicely, and I used TBMST to test HexPi’s legs.

The good news: All the legs wiggled!

The bad news: About 1/3rd of the MG-995’s are pretty pathetic at holding their set points at 5V with 3000uF of electrolytic capacitors filtering a 7.2V 2000mAh NiCd battery pack.

I’ll add more large capacitors, but it may come down to testing all 49 MG-995’s and picking the best 18 for HexPi.

I will disassemble the worst servo of the lot, and see if I can figure out WHY it is so bad.
You can buy ginseng in in various countries across the world. unica-web.com viagra ordination is certainly a most recommended brand because it does not have major problems when you map it against parallel products from various companies. You may approach to lodge a side effects of cialis complaint for the false type of drugs. Pharmacies viagra no prescription mastercard selling anti-impotency drug without looking at doctor’s prescription sell counterfeit drugs that are good for nothing. A popular generic soft cialis remedy that is commonly prescribed by many physicians to treat erectile dysfunction.
Coming soon: A video of HexPi’s legs being wiggled by TBMST!

Links:

The Better Mousetrap Servo Tester https://www.mikronauts.com/robot-zoo/hexpi-hexapod-pi-robot/

HexPi the RoboPi + Raspberry Pi hexapod robot https://www.mikronauts.com/the-better-mousetrap-servo-tester/

The new RoboPi software is ready!

This version adds:

• readDistance(pin) for HCSR-04 ultrasonic range sensor
• improves servo and PWM resolution to 5 microsecond timing grain

So it’s up to you to learn how to visualize the problem area cialis 5mg tablets and what’s more important – the better condition like if you’re already feeling better. It is especially convenient form of Sildenafil for those people, who have been hit below the belt, are identified to knowledge fewer aspect results compared to buy cheapest viagra other accessible PDE5 inhibitors.The mild and most popular part consequences are headaches, nasal congestion, flushing. The name of the medicine was vardenafil vs viagra . With a single pill erection cannot take place you need to have it as per prescribed tadalafil free shipping glacialridgebyway.com by your doctor.
The new software is available on the product page at:

https://www.mikronauts.com/raspberry-pi/robopi/

Please note:

readDistance() should also work with the Parallax Ping sensor, and may also work with the SeeedStudio range sensor.

I will be testing both of those sensors shortly.